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Grassland Farmers – Opportunities, Threats & Realities26th Annual Conference of The Grassland Society of NSW Inc.

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www.grasslandnsw.com.au

Grassland Farmers – Opportunities, Threats & Realities26th Annual Conference of The Grassland Society of NSW Inc.

B A T H U R S T 2 6 – 2 8 j U ly 2 0 1 1

www.grasslandnsw.com.au

Proceedings of the 26th Annual Conference of The Grassland Society of NSW2

The Grassland Society of NSW was formed in March 1985. The Society now has about 500 members and associates, 75% of whom are farmers and graziers. The balance are agricultural scientists, farm advisers, consultants and executives or representatives of organisations concerned with fertilisers, seeds, chemicals and machinery.

The aims of the Society are to advance the investigation of problems affecting grasslands husbandry and to encourage the adoption into practice of results of research and practical experience. The Society holds an annual conference, publishes a quarterly newsletter, holds field days, and has established regional branches throughout the State.

Membership is open to any person or company interested in grassland management and the aims of the Society.

STATE EXECUTIVE 2010/11

Mick Duncan (President)

Lester McCormick (Vice President)

Janelle Witschi (Secretary)

Frank McRae (Treasurer)

Keith Garlick (Sponsorship)

Committee:

Linda Ayres, John Ive, David Harbison, John Coughlan, Hugh Dove, Philip Stacy, Carol Harris, Cathy Waters, Hayley Rutherford

Life Members: Malcolm Campbell, Peter Wrigley,

Haydn Lloyd Davies, Warren McDonald, Jim Dellow

BRANCH REPRESENTATIVES 2010/11North Western Slopes Loretta Serafin

Central John Coughlan

Southern Tablelands Mike Keys

South Western Slopes and Riverina Hayley Rutherford and Nathan Ferguson

Western Slopes and Plains Cathy Waters

Northern Tablelands Mick Duncan

2011 Conference Committee:Convenor: David Harbison (D R Agriculture Pty Ltd,

Molong)

Treasurer: Stuart Green (Mandurama)

Secretary: Janelle Witschi (The Grassland Society of

NSW, Orange)

Editorial: Greg Lodge (Tamworth Agricultural

Institute, Calala) Jim Scott, (University of New England, Arrmidale) Warwick Wheatley (Charles Sturt University, Orange)

Proceedings Design and Layout: Barry Jensen (Orange)

The Grassland Society of NSWA unique blend of people with a common interest in developing

our most important resource – our Grasslands

Proceedings of the 26th Annual Conference of The Grassland Society of NSW 3

Sponsorship: Keith Garlick (The Rural Centre, Orange)

Speakers: David Harbison (D R Agriculture Pty Ltd,

Molong) Linda Ayres (Orange Agricultural Institute, Orange) Karl Behrendt (Charles Sturt University, Bathurst) Frank McRae (AusWest Seeds) Ross Yelland (Elders, Orange)

Hay and Silage Competition: Neil Griffiths (DPI NSW, Paterson)

Trade Display: Jonathon Tink (Wrightson Seeds, Orange)

Adrian Keith, (AusWest Seeds, Forbes)

Advertising: Keith Garlick (The Rural Centre, Orange) Janelle Witschi (The Grassland Society of

NSW, Orange) Bernadette York (Orange Agricultural Institute, Orange)

Field Tours: Ross Yelland (Elders, Orange)

Jonathon Tink (Wrightson Seeds) Stuart Moncrieff (Elders, Orange) Frank McRae (AusWest Seeds)

Audio and Presentations: Adrian Keith (AusWest Seeds, Forbes)

Tony Cox (Orange Agricultural Institute, Orange)

Committee Members: Karl Anderson, Warwick Badgery, John

Coughlan, Roy Elton, Jenene Kidston, Hayley Rutherford

ISBN 978 1 74256 213 1

Citation: Proceedings of the 26th Annual

Conference of The Grassland Society of NSW Inc.

© The Grassland Society of NSW Inc. 2011 Eds G Lodge, W Wheatley, J Scott (The Grassland Society of NSW, Orange)

Enquiries and additional copies:The Grassland Society of NSW PO Box 471, Orange NSW 2800 Email: [email protected] Website: www.grasslandnsw.com.au

Disclaimers

The information contained in this publication is based on knowledge and understanding at the time of writing (July 2011). However, because of advances in knowledge, users are reminded of the need to ensure that information upon which they rely is up to date and to check the currency of the information with the appropriate adviser. The product trade names in this publication are supplied on the understanding that no preference between equivalent products is intended and that inclusion of a product name does not imply endorsement by The Grassland Society of NSW Inc. over any equivalent product from another manufacturer.

mailto:[email protected]

http://www.grasslandnsw.com.au


Conference SponsorsThe Executive of The Grassland Society of NSW acknowledge sponsors for their generous support of the Conference. Without this sponsorship in cash and kind, it would not be possible to keep the cost of the Conference within acceptable limits.

Premier sponsors

Major sponsors

Corporate sponsors

Local sponsors

11 KIRKCALDY STREET

BATHURST


ContentsThe Grassland Society of NSW .......................................................................................................2Conference Sponsors .......................................................................................................................4Preface .............................................................................................................................................7Invited papers ................................................................................................................................11

Threats, realities and opportunities of grassland farming in the central Tablelands – K. Behrendt and J. Eppleston ............................................................ 12

Farming the grass curve in the context of changing opportunities in the Australian lamb market − a central Tablelands perspective – G.M. and G.J. Salmon ............................................ 23

Developing livestock preventive medicine programs with grassland farmers – B.R. Watt ............... 30Performance for profit – M. Ryan.......................................................................................................... 34Pseudo-science: a threat to agriculture? – D.C. Edmeades ................................................................. 38Soil chemistry – facts and fiction and their influence on the fertiliser decision making

process – N. Menzies, D. Harbison and P. Dart ............................................................................. 49The Pegala Pastoral Company − Vertically integrating cropping and beef production systems – B. Hackney, P. Orchard, D. Kemp, B. Orchard ................................................................................... 67Landscape and grazing management affects on pasture production and persistence on

“Dunns Plains” – B. Townson .......................................................................................................... 74Collaborate to survive and thrive – J. Gladigau ................................................................................... 78Cereal based forage crops for hay and silage production – J. Piltz, C. Rodham, J. Walker, P.

Matthews, B. Hackney and J.F. Wilkins ......................................................................................... 81Optimising the intake of feed by pasture-fed sheep and cattle – C.T. Westwood ............................. 88Varying sheep production from different pasture types – J. Brien ...................................................... 99

Contributed papers .....................................................................................................................104Bioscapes − an introduction to biodiversity in grazing landscapes – C. Edwards .......................... 105Surveys of grazing industry end-users in northern New South Wales – G.M. Lodge .................... 107On-farm monitoring of sheep and pasture production in the EverGraze northern New South

Wales project – G.M. Lodge, M.A. Brennan, P.T. Sanson, B.R. Roworth and I.J. Stace ......... 111Developing pasture and livestock benchmarks for sheep production in northern New South

Wales – G.M. Lodge ....................................................................................................................... 115Comparison of methods for estimating herbage mass in small plots – G. M. Lodge and

S. Harden ......................................................................................................................................... 119Using height and density to estimate the herbage mass of different pastures in northern New

South Wales – G.M. Lodge, M.A. Brennan, P.T. Sanson, B.R. Roworth and I.J. Stace ........... 123“Trevenna” sheep production demonstration site of methane emissions on the northern

Tablelands of NSW – C. Edwards, M.J. McPhee, J. Meckiff, N. Ballie, D. Schneider and R. HegartyC ............................................................................................................................. 127

Using near infrared reflectance spectroscopy (NIRS) to determine nutritive value of tropical perennial grasses – S.P. Boschma, S.A. Sissons and M.J. Sissons............................................... 129

Herbicides evaluated for tropical perennial grasses – L.H. McCormick, S.P. Boschma, A.S. Cook and B.M. McCorkell .................................................................................................... 133


The value of ‘alternative’ nitrogen fertiliser products on pasture. 1. Pasture production at three sites – C.E. Muir, N. Griffiths and P. Beale ............................... 136

The value of ‘alternative’ nitrogen fertiliser products on pasture. 2. Pasture quality and carryover effects at Tocal – C.E. Muir, N. Griffiths and P. Beale ......... 140

The use of pig manure – a study at Wollun, NSW – C. Edwards and M. Duncan ........................ 143Poster papers ...............................................................................................................................146

Investigating the impact of cover cropping on a native pasture system in southern Queensland – L. Bailey, S. Murphy and C. Guppy ................................................ 147

Managing tropical perennial grasses for livestock production – a case study – B.R. McGufficke ........................................................................................................................... 149

Benefits and uses of plantain (Plantago lanceolata) cv. Ceres Tonic in livestock production systems in New South Wales – H.G Judson and A.J.E. Moorhead ............................................ 151

Australian breeding of persistent perennial ryegrass without endophyte – A. Leddin ................... 153Effect of ensiling on weed seed viability – J. Piltz, R. Stanton, C. Rodham and H.Wu .................. 156

Travel grant report ......................................................................................................................157Report of travel to New Zealand to attend the 15th Australian Society

of Agronomy Conference and visit two NZ Agresearch Institutes – M.R. Norton .................... 158

A great grazingalternative to canola• Ideal alternative in a cereal cropping rotation

• High quality fodder crop, ideal for stock finishing systems

• Multiple grazing option with excellent regrowth potential

• Tolerant of hot, dry conditions once established

• Early maturing, 10-12 weeks

For further information check out the latest BRASSICA brochure.

For further information and advice contact one of our territory managers or visit our website www.agricom.com.au

Dick Evans Sven Koljo Jacob O’BrienSth VIC, TAS, SA, WA Nth Vic, Sth NSW Nth and Nth Coast NSWm 0418 579 220 m 0427 772 488 m 0428 469 363

Another quality cultivar from . . .

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AGRICOMproud sponsors of

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Winfred_176x100_Layout 1 30/05/11 9:56 AM Page 1


Preface

I extend a very warm welcome to all members attending this 26th annual conference of the Grassland Society of NSW.

An equally warm welcome to those who are not members of the Society. I encourage you to join us and enjoy the many benefits of membership, well worth the annual subscription of $50.00.

This is the first conference to be held at Bathurst. We all look forward to a stimulating two days including the farm tours of the district. The tours are an important feature of our conferences and invariably provide visitors to the district with an insight into agricultural production at the local level.

Plant and animal production depend on new technologies to complement established agricultural science. The Grassland Society brings together producers, agronomists, agri-business firms, animal scientists and teachers of agriculture to receive, discuss and exchange high quality information relevant to grassland farming. One important objective of the Society is to promote agricultural systems that combine improved efficiencies and environmental responsibility. Pastures, both native and introduced, are the powerhouse of all forms of agriculture across Australia. Above ground, pastures sustain grazing animals, suppress weed invasion and protect otherwise bare ground from erosion. Of equal importance, they provide for microbial activity under the ground. Pastures both depend on and improve soil health.

This conference examines aspects of soil fertility, pasture management and animal performance. In addition, threats to and realities of agricultural systems, from natural and human sources are discussed by prominent scientists and producers.

The organising Committee has put much time and effort into selecting expert speakers to bring delegates up to date with current and new aspects of pasture and animal science. The conference team is to be congratulated and

thanked for putting together such a stimulating program of formal sessions and farm tours.

I would like to acknowledge our many sponsors representing corporate and government sectors that regularly support the Grassland Society. Conferences of this nature do not happen without the substantial assistance of our sponsors. Furthermore, I encourage all conference delegates to visit the well-prepared commercial displays, exhibits and posters. They are full of current information on new pasture varieties, fertiliser products, herbicides and management strategies, all aimed at assisting producers and their advisers. Please take time to talk with representatives of the trade exhibits and poster authors. They are a valuable source of information and are always happy to discuss developments with conference delegates.

Finally, I thank all of you who are here to enjoy and learn from this conference. The Grassland Society is keen to maintain the high standards of previous years, and we invite suggestions to improve future activities. Please feel free to let any member of the Organising Committee know your thoughts in this regard. After all, the Grassland Society is only as effective as its members and depends on them for continued existence. I again encourage non-members to join and enjoy the many benefits of membership. Application forms can be printed from our internet site: www.grasslandnsw.com.au and are available from the registration desk at this conference.

Best wishes for a most enjoyable conference.

Mick Duncan President

A great grazingalternative to canola• Ideal alternative in a cereal cropping rotation

• High quality fodder crop, ideal for stock finishing systems

• Multiple grazing option with excellent regrowth potential

• Tolerant of hot, dry conditions once established

• Early maturing, 10-12 weeks

For further information check out the latest BRASSICA brochure.

For further information and advice contact one of our territory managers or visit our website www.agricom.com.au

Dick Evans Sven Koljo Jacob O’BrienSth VIC, TAS, SA, WA Nth Vic, Sth NSW Nth and Nth Coast NSWm 0418 579 220 m 0427 772 488 m 0428 469 363

Another quality cultivar from . . .

www.agricom.com.au

AGRICOMproud sponsors of

the Grasslands Society

Winfred_176x100_Layout 1 30/05/11 9:56 AM Page 1

http://www.grasslandnsw.com.au


Conference Program Tuesday 26 July 20111:00–5:00 pm Pre-conference tourist attractions (at your own leisure)

4:00–6:00 pm PRE-CONFERENCE REGISTRATIONS – Citigate, 1 Conrod Straight, Mt Panorama.

6:00 pm THE GRASSLAND SOCIETY OF NSW ANNUAL GENERAL MEETING – Citigate, Mt Panorama, 1 Conrod Straight, Bathurst.

Day One – Wednesday 27 July

7:30–8:30 am REGISTRATIONS

8:30 am WELCOME – President of the Grassland Society of NSW, Michael Duncan.

Session 1

9:15 am ‘The threats, realities and opportunities of grassland farming in the Central Tablelands’. Dr Karl Behrendt – Lecturer in Agribusiness and Director of the Asian Agribusiness Research Centre at Charles Sturt University, Orange. Jeff Eppleston – research officer with the Tablelands LHPA where he is responsible for animal health and production research relevant to local sheep and cattle producers. He is also a commercial White Suffolk ram breeder.

10:00 am ‘Farming the grass curve with lamb on the Central Tablelands of NSW – opportunities, threats and realities’. Gillian and Geoff Salmon, “Ambleside”, Oberon. Prime lamb and beef producers who share a passion for sustainable grazing systems. The aim of their enterprise is to maximise feed use efficiency by matching their target markets to their pasture curve.

10:30 am POSTER PAPERS, MORNING TEA & TRADE DISPLAYS

Session 2

11:15 am ‘An overview of animal health as a constraint in grazing systems on the Tablelands’. Bruce Watt Senior District Veterinarian, Tablelands Livestock Health and Pest Authority, Bathurst.

12:00 noon ‘Performance for profit’. Matt Ryan, producer, “Kilcooly”, Rydal.

Session 3

12:30 pm LUNCH AND BUS TOURS DEPART

5:30 pm BUS TOURS RETURN

6:30–7:00 pm PRE-DINNER DRINKS and CANAPES

7:00 pm CONFERENCE DINNER AND GUEST SPEAKER

HAY AND SILAGE COMPETITION


Day Two – Thursday 28 July

8:30 am ‘Pseudo Science – a threat to agriculture’. Dr Doug Edmeades, Managing Director, agKnowledge Ltd, NZ.

9:15 am ‘Soil chemistry – Facts and fiction, and their impact on the fertiliser decision making process’. Neil Menzies, Professor of soil and environmental science and Dean of Agriculture, University of QLD. Respected soil scientist who believes that land management should be based on understanding not faith.

9:55 am ‘Pegela Pastoral Company – vertically integrating cropping and beef production systems’. Mark Mason, B.Ec, Director, Pegela Pastoral Co.

10:25–11:00 am MORNING TEA AND TRADE DISPLAYS

Session 4 Pastures and landscapes

11:00 am ‘Factors affecting pasture production in variable landscapes – how does it influence fertiliser use and other management issues?’ Dr Belinda Hackney, Research Agronomist, DPI, Bathurst.

11:45 am ‘Landscape and grazing management affects on pasture production and persistence on Dunn’s Plains.’ Bruce Townson, producer, “Dunns Plains”, Rockley.

12:15 pm ‘Collaborate to survive and thrive.’ John Gladigau, Nuffield Scholar, Bulla Burra Collaborative Farming Australia, “Bunyarra”, Alawoona, South Australia.

1:00–1:45 pm LUNCH AND TRADE DISPLAYS

Session 5

1:45 pm ‘Cereal based forage crops for hay and silage production.’ John Piltz, Livestock Research Officer, DPI, Wagga Wagga.

2:30 pm ‘Optimising the intake of feed by pasture fed sheep and cattle’. Dr Charlotte Westwood, Wrightson Seeds.

3:00 pm ‘Varying sheep production from different pasture types.’ Julie Brien, Nuffield Scholar and producer, “Ardnai”, Greenethorpe.

3:30–3:45 pm CLOSE AND AFTERNOON TEA

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Invited papers


Threats, realities and opportunities of grassland farming in the central Tablelands

K. BehrendtA and J. EpplestonB

ASchool of Agricultural and Wine Sciences, Charles Sturt University, Orange NSW 2800; [email protected]

BTablelands Livestock Health & Pest Authority, Bathurst, NSW 2795.

Abstract: Grassland farming on the central Tablelands of New South Wales is faced with many challenges. From a resource perspective it is diverse and has evolved in response to soil, land capability, climatic and investment constraints. From a resource use perspective, the operating environment for grassland managers is strongly influenced by external demands from non-traditional users of grassland resources. These interactions are reviewed and investigated to enhance the understanding of the threats, realities and opportunities of grassland farming in the region. In addition, the historical returns from grassland farming in the region are disaggregated to demonstrate the contributions to personal wealth creation of the competition for grassland resources, as well as their use as a harvestable resource. The results of the study indicate that inherent capital appreciation of land and the opportunity for subdivisional development have the greatest impact on returns from investment in grasslands. However, it also highlights the opportunities for these returns to be enhanced through prudent and efficient management of the livestock enterprises being run on the resource. Using the process applied in this study, it is also possible for agricultural investors to spatially analyse where appropriate investments exist in grasslands.

Key words: Grassland resource competition, livestock enterprise demographics, pasture production and variability, risk and returns

IntroductionThe central Tablelands of New South Wales (NSW) covers an area of approximately 13,700 square kilometres. Bathurst was proclaimed a town 1815 and is Australia’s first inland settlement and the oldest inland city. The central Tablelands maintains a population of around 110,000 and includes the major regional centres of Orange, Blayney, Oberon and Lithgow. Historically, agricultural enterprises have largely dominated the economy in the region, even through the gold rush era of the 1850−70s, however, more recently the region has developed a diverse modern economy based on manufacturing, agriculture, forestry, education, mining, and tourism. As the region continues to develop, there is increasing competition for the grassland resources that exist in the region. This competition not only comes from some of these diverse industries, but also extends to the demand for its amenity value and its use

for lifestyle purposes, biodiversity and broader catchment values.

The aim of this paper is to provide an overview of the current state of the region. It also reviews the threats, realities and opportunities to grassland farming in the region. This includes the influence of the increasing competition for grassland, soil and human resources on the regions potential for food and fibre production.

Agro-ecology of the central TablelandsThe region lies in the temperate climate zone and the region experiences no distinct dry season. The lower altitude areas tend to have a warm summer, whereas the higher altitude areas have a mild summer (Figure 1). The whole region is prone to severe frosts, with higher areas receiving occasional snowfalls. Rainfall tends to exhibit slight summer dominance within the Bathurst basin and to the north of this area, with the long-term annual average rainfall around 630 mm per annum, although rainfall variability increases during the summer and early autumn. In the higher altitude areas of the region,



rainfall exhibits a uniform distribution with a long-term average annual rainfall of over 800 mm per annum. The lower altitude areas have lower autumn, winter and early spring rainfall, and warmer summers than the higher altitude areas.

The spatial distribution of average annual rainfall and land capability classes (Emery 1986), are shown in Figures 2a and 2b. It shows that the areas surrounding and north of Bathurst receive the lowest annual rainfall (600−700 mm per annum), while, apart from the pocket of higher average annual rainfall surrounding Orange, the highest rainfall (>1000 mm) in the region is received in the higher altitude areas in the eastern part of the region. These climatic effects are reflected in the predicted pasture growth curves for these areas within the region (Figure 3).

The spatial distribution of the different land capability classes is strongly influenced by the predominant soil types, as well as its topography. To the south of Bathurst we mainly find granite derived soils with some slate/shale and basalt derived soils interspersed on predominantly class 3, 4 and 5 lands. To the north, slate/shale and granite derived soils predominate on class 5, 6 and 7 lands. In areas both east and west of Bathurst (south of Oberon and Orange), we find extensive areas of basalt derived soils interspersed amongst granite and slate/shale derived soils, especially at higher altitudes on

class 2−4 country. In the lower areas of the landscape immediately around Bathurst, we find granite derived soils (Red Gradational or Red Podzolic soils) predominating on class 2, 3 and 4 lands, with some large areas of class 1 land on alluvial soils along the Macquarie river and its tributaries. These areas contribute markedly to the regional economy through valuable horticultural and lucerne industries. On the surrounding ridgelines around the Bathurst basin we find granite and slate/shale derived soils distributed across class 3, 4 and 5 lands. The predominant land capability class in the region is class 4 land (19.1%), followed closely by class 6 (18.7% grazing only) (Figure 2b). Only 11.4% of the region is capable of maintaining regular cultivation, with 31% suitable for grazing with occasional cultivation. In total, 14.3% is classed as not suitable to agricultural enterprises (class 7 and 8 land). State forests and national parks dominate the remainder of land in the region, with 21% of the region used for these purposes.

In combination, the regions soil types, rainfall distribution and land capability have strongly influenced the evolution and spatial distribution of agricultural land use (Figure 2c). The role of native pastures in the region is significant and highlights the challenging environment being managed by land holders north of Bathurst. It is a lower rainfall environment on class 5−7 country with low temperatures for 4−6 months (especially for frost sensitive species). Soil structure and

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a) Bathurst (Elevation 713m) b) Oberon (Elevation 1095m)

Figure 1: Average monthly rainfall (bar) over the period of 1908–2011, mean maximum ( ) and mean minimum (--) temperatures for a) Bathurst and b) Oberon since 1966 (BOM, 2011).


a) Average annual rainfall

b) Assessed Land capability


c) Land use

Figure 2: Spa al distribu on of a) Average annual rainfall over period of 1910 to 2010 (BOM, 2011); b) land capability (OEH, 2008 ) based on the method described by Emery (1986) ; and c) land use in the Central Tablelands region (ABARE, 2009 ).

Figure 2: Spatial distribution of a) Average annual rainfall over period of 1910 to 2010 (BOM, 2011); b) land capability (OEH, 2008) based on the method described by Emery (1986) ; and c) land use in the central Tablelands region (ABARE, 2009).

fertility is poorer and the landscape dominated by native pastures. In total, just 8% of the region (1115 km2) is used for grazing natural vegetation. Of greater importance is the role of modified pastures (with sown introduced species) found predominantly south of the Great Western Highway, with 45% of the region (6229 km2) used for grazing modified pastures. Although representing a higher rainfall zone within the region, inherent soil fertility issues and the diversity of landscapes, presents a challenge to the sustainable use of these modified pastures in combination with native and naturalised species, for extensive livestock production.

The most prevalent soil fertility issues in the region include soil acidity and deficiencies in phosphorus (P), nitrogen (N), and in many instances sulfur. Molybdenum, selenium and potassium deficiencies are also common, and often their correction produces significant benefits to pasture production and animal health.

Aluminium toxicity is also often a problem in strongly acidic soils.

Regional grasslandsNative grass-based pastures are widespread throughout the region with the dominant species being wallaby grass (Austrodanthonia spp.), redgrass (Bothriochloa macra) and weeping grass (Microlaena stipoides) (Garden et al. 2001). Other co-dominant and sub-dominant species include poa tussock (Poa spp.), kangaroo grass (Themeda australis), spear grass (Austrostipa scabra) and purple wire grass (Aristida ramosa), particularly on the granite and slate/shale derived soils north of the Great Western Highway. Other species that are commonly found in native pastures across the whole region include annual grasses such as silver grass (Vulpia spp.) and brome (Bromus spp.), and legumes such as subterranean clover (Trifolium subterraneum) and native glycine (Glycine spp.).


Modified pastures are also found throughout the region, but particularly in the higher rainfall areas where Red Earth and Red Podzolic soils predominate. The dominant species in these pastures are subterranean clover, perennial ryegrass (Lolium perenne), annual ryegrass (L. rigidums), white clover (T. repens) and silver grass (Kemp and Dowling 1991). Other sub-dominant species include brome, phalaris (Phalaris aquatic), cocksfoot (Dactylis glomerata), barley grass (Hordeum leporinum), and other native grasses such as wallaby grass and redgrass. These modified pastures are often limited in their productivity and persistence due to sub-optimal soil fertility regimes and grazing management. In addition, across all landscapes and pastures found within the region, perennial weeds such as serrated tussock (Nasella trichotoma), chilean needle grass (N. neesiana), and St. Johns wort (Hypericum perforatum); and in class 4 lands and above, biddy bush (Cassinia spp.), may also be found in economically damaging concentrations (Dellow et al. 2002).

The influence of the region’s agro-ecology on potential pasture production can be examined using GrassGro modelling (Moore et al. 1997). This decision support tool was used to estimate the expected median pasture growth rates for a typical modified pasture, which maintains introduced species, in the low altitude/low rainfall zones of the region (Figure 3a), as well as in the high altitude/high rainfall zones (Figure

3b). On average, both zones are expected to produce around 8.5−8.7 tonnes of dry matter per hectare per annum (t DM/ha/yr), whereas, native pastures north of Bathurst on granite and shale/slate derived soils would be expected to only produce around 3−5 t DM/ha/yr. The distribution of pasture growth during the growing season is notably different between low and high altitude zones. Although maintaining similar average growing season lengths of around 10 months, the higher altitude zones have a noticeably lower pasture growth rate potential during the winter months. This winter ‘bottleneck’ can potentially severely constrain the potential utilisation of pasture resources and reduce productivity if not appropriately managed. Adjusting the timing of peak feed demand by livestock enterprises, the use of tradable stock, fodder cropping, and fodder conservation are popular methods of improving pasture utilisation and increasing winter carrying capacity. These strategies also interact with the risk profile of the enterprises being operated (Behrendt et al. 2000).

Figure 3 indicates the variation in daily pasture growth rates for modified pastures between the two zones. The higher altitude zones maintain marginally less variation in their pasture growth rates, albeit at much lower levels during the winter periods. The advantage gained from the higher altitude regions is the relatively mild summer and higher rainfall during the autumn, winter and early spring; which in combination

Figure 3: Variability of pasture production at Bathurst (a) and in the higher tablelands regions above 900 metres altitude. Pasture growth percentiles shown are 10th percentile (∙∙∙∙), median ( ) and 90th percentile (---) levels for GrassGro simulation data over the period of 1980 to 2009.

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with lower evapotranspiration rates, increases potential autumn pasture growth rates and maintains higher minimum spring pasture growth rates. In combination though, given the large within and between season variability, the autumns tend to be unreliable for pasture growth (Leech and Keys 2000). This can have severe implications for the winter feed gap, especially when the autumn does not produce an opportunity for pasture growth.

Grassland farming practicesTraditionally the grasslands in this region were utilised by the grazing of native pastures by herds and flocks that settlers established after the region was settled during the early 1800s. This continued until around 1950s when the benefit of superphosphate and subterranean clover to total DM production was demonstrated (Crofts 1997). In the 1950−1970s, there was a rapid introduction of perennial pastures and these responded better to the increased levels of N fixed by the introduced clovers with elevated soil P levels.

Data on the numbers of sheep and cattle collected annually since 1990 were obtained from the database held by the Tablelands Livestock Health and Pest Authority (TLHPA). This data has been used to analyse the recent changes in livestock enterprise demographics and grazing pressure in the study region (Figure 4). Because there had been a number of amalgamations over this time, only data from properties located within the study region (Figure 2) were analysed, which excluded the broader constituency of the TLHPA.

There are a number of reasons hypothesised as causing the changes in enterprise demographics detailed in Figure 4. The demise of the reserve price scheme for wool in February 1991 triggered a shift from dedicated sheep producers to increasing numbers of specialised cattle producers. Secondly, the prolonged drought over the period 2000−09 favoured reduced stock numbers. Thirdly, an increase in the demand for and availability of off-farm work stimulated a move into enterprises such as cattle with lesser labour demands. Finally, with the increase in the number of rural subdivisions, hobby farmers

sought enterprises requiring lower labour inputs.

Another contributing factor to the change in enterprise demographics is the increasing beef prices observed during the late 1990s during a period where sheep and wool prices remained stable at relatively low levels. This may have induced a change from sheep to cattle. More recently, with increasing and high sheep prices and profitability, the cost of shifting back into sheep from cattle may be impeding change. The data presented in Figure 4c also indicates that the average scale of central Tablelands enterprises is small compared with state standards. It also indicates that specialist cattle producers scale stayed relatively constant over the reported period, and the main enterprise change (from sheep to cattle) occurred by mixed enterprise operations shifting from sheep to cattle, although some attrition occurred in number of specialist sheep producers since 2000−01 (Figure 4b). The notable reduction in sheep numbers from around 2 million in 1990 to 500,000 in 2010, is consistent with national trends (Curtis 2009), albeit at a slightly higher rate of decline. Although there has been an increase in number of cattle enterprises, their scale is reducing. From a producer’s perspective this creates issues for marketing and market power, and from a buyers or processors perspective, it presents a supply chain management issue as the market is becoming increasingly fragmented. The introduction of the CLTX was a positive step towards dealing with this imbalance of market power that was being created in the regions traditional market places due to an increasingly fragmented industry. The same issue has been faced by prime lamb producers and their customers.

Evidence also suggests that many of the sheep enterprises tend to be operated in the lower stocking rate areas. Their average stocking rate has been in the vicinity of 3−5 dry sheep equivalents (DSE)/ha, whereas cattle and mixed enterprises average 5−8 DSE/ha. Merino sheep based enterprises dominate the area north of the Great Western Highway, and given the agro-ecology of this zone, it provides less opportunity to move into cattle and away from Merino based enterprises. Typically, Merino enterprises are also


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found on the higher land classes (5 and above), whereas prime lamb and cattle enterprises are found on modified pastures in the southern and eastern parts of the region on class 3−5 country.

In summary, the regions soils and pasture resources can achieve high levels of production, especially in the higher rainfall zones. The length of the potential growing season at 9−10 months provides a feed profile capable of sustaining high levels of livestock production. However, the risks of production at lower altitudes and the winter bottle neck at higher altitudes, means

that grassland managers need to develop flexible management systems that try to make the most of pasture resources when they become available. At the average district stocking rate of 2−5 DSE/ha within low rainfall zones north of Bathurst, and 6−10 DSE/ha in high rainfall/high altitude zones, most producers will, on average, only utilise 20−30% of pasture grown. There is a significant capacity for the central Tablelands to increase regional meat and wool production. The challenge is how this will be achieved given climate risk and external competition for grassland resources.


Challenges of managing a grassland-based businessInvestment into soil fertility in parts of the region have produced known and substantial benefits to production and economics, especially in the high rainfall zones of the region in conjunction with modified pastures (Vere 1998; Behrendt 2005). Single superphosphate applications plus aerially sown subterranean clover on native pastures on the granite and shale/slate derived soils in hill country north of Bathurst, have also shown to be capable of sustainably increasing carrying capacity from 2 DSE/ha to 6−8 DSE/ha over 12 years. That is, an increase of around 5 DSE/ha for every tonne of single superphosphate applied (Crofts 1989). These increases in stocking rate were found to be maintained with continued applications of 125 kg/ha of single superphosphate every second or third year. Such responses on native species dominated pastures is also supported in acidic country in the Newbridge area south of Bathurst using both reactive phosphate rock and single superphosphate (Keys and Clements 2006). If consideration is given not only to the need for higher pasture production to improve the livestock production economics, but also consider the interaction between soil fertility and the resilience of modified and native pasture systems, then the application of fertiliser in Tablelands grassland systems would not be considered a discretionary expense, even with the increasing costs of single superphosphate (Scott and Cacho 2000; Behrendt et al. 2009).

A significant challenge to grassland farmers in the central Tablelands of NSW is the increasing demands for the regions soil and pasture resources. The average grazing area for a rural holding in this region has steadily declined since 1990, from around 195 ha down to 165 ha in 2010. This coincides with the continued growth in the number of separate land titles within the region, which has found to be economically beneficial to the region (WRI 2005). The ongoing subdivision of grazing lands, conceptually, is a double edged sword, as it provides both a significant threat and opportunity to grassland farming in the region.

Grassland risks and returnsIn reviewing the historical changes in rural land markets in the region, it demonstrates the effect of competition for grassland resources, climate and commodity prices on the profitability of managing grasslands (Table 1 and Figure 5). Land value data was sourced from the NSW Land and Property Information Authority (2010), with historical enterprise returns estimated using GrassGro simulation data, annual average commodity price data, and historical farm survey data for the region.

Grazing properties in the Orange and Bathurst areas have historically achieved higher rates of land capital appreciation than at Oberon. The demand from these properties is largely being driven by investor speculation relating to the future subdivision potential, as well as rural lifestyle investors (some focused on intensive agriculture), rather than the professional grazier. The potential gains from subdivision, even from only small developments (2−3 concessional lots) are significant. The value of converting grazing country to hobby lots is an 2−3-fold increase in land value, with conversion into rural residential being 23−33-fold increase in land value (less the costs of development). This does present a significant opportunity to the Tablelands grassland farmer for personal wealth development, especially those landholders within commuting distance of major regional centres. But, it also presents a threat to maintaining of expanding agricultural production from the traditional industries (beef and sheep), as the higher land prices makes investment uneconomical. However, the overall benefit to the gross regional product is positive from such development, with the change in agricultural production demographics from the traditional enterprises to more intensive enterprises, having been shown to have flow-on effects into the broader economy (WRI 2005).

Typically, the returns on investment in grassland resources in the region are derived from both the capital appreciation of the grassland resource and the potential yield or return from operating traditional livestock enterprises. For the more risk averse investor, an investment in grazing


Table 1. Regional livestock and land value data (LPIA 2010); and rates of return from investment in grasslands over the period of 1996−2010, in the central Tablelands, NSW. All figures are in nominal terms, with real terms figures in parentheses.

Measure

Property type

Grazing Hobby Rural residential

Bathurst Oberon Orange Bathurst Orange Bathurst Orange

Area (ha) 683 191 238 40.2 39.9 2.46 2.17

Scale (DSEs) 3,100 2,400 3000

2010 Land value/ha ($) 3,411 3,398 5,420 10,771 12,657 112,602 123,502

2010 Land value/DSE ($) 752 270 430

Investment performance measures

Compound rate of gain in livestock assets

4.7% (2.3%)

5.3% (2.8%)

5.3% (2.8%)

Compound rate of gain in land assets

6.2% (3.9%)

3.8% (1.5%)

8.2% (6.6%)

6.6% (4.3%)

8.8% (6.4%)

8.4% (6.0%)

8.0% (5.6%)

Average nominal annual yield from grazing enterprises (Return on total assets including capital appreciation)

6.6% 6.0% 10.2%

Figure 5. Annual average returns and risks on investments in () grazing land, () livestock and () whole farm operations in the Bathurst, Oberon and Orange areas.

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land around Bathurst will represent the least risky investment. In disaggregating the whole farm returns, it can be shown that this is not due to its risk and return profile from the livestock enterprises being run in that region, but rather due to the lower risk capital appreciation of land assets. The livestock enterprises around Bathurst actually represent the most risky investment with concurrent low returns. For the more risk neutral investor, investing in grazing land at Orange would represent a more appropriate investment. For both the Oberon and Orange areas, which reflect the high rainfall/high altitude zones of the region, livestock returns significantly outperform those achieved within the lower rainfall zones of the region, and with significantly less risk. This results from the higher rainfall and longer growing season areas being capable of maintaining higher annual average stocking rates, as well as having lower risks of production than those lower rainfall regions surrounding and north of Bathurst.

The variability around this typical representation of historical enterprise and whole farm performance is substantial. There is evidence of high performing producers in the central Tablelands regions achieving annual whole farm yields (returns on assets including capital appreciation) in excess of 10%, even in the lower rainfall areas surrounding Bathurst. This diversity is being achieved through efficient and flexible management systems, using profitable livestock enterprise structures with higher than district average stocking rates. Enterprise scale itself is not a key driver of productivity in farming systems, but rather the capacity of smaller land holders to cost-effectively access advanced technologies (Sheng et al. 2011). There are obviously opportunities emerging for service providers of such technologies to fulfil such a need in this region. Given the cost of expansion, intensification of a grassland farmer’s existing operation and accessing of technologies provide the best opportunity for improving profitability of enterprise committed managers. Although it would be expected that significant gains in scale and technology adoption could be achieved through amalgamation of livestock enterprises across properties through ingenious

land development, share farming and leasing arrangements.

ConclusionsThe central Tablelands region of NSW is a challenging and diverse environment. The current practices applied and the distribution of land use in the region is strongly correlated with the agro-ecology of the region. In addition, competition for grassland resources from non-traditional uses (traditional uses being for broad acre livestock production) has caused the evolution of a region characterised by small scale holdings, high land values of grassland resources, and reducing regional production from traditional agricultural enterprises. The realities are that this competition for grassland resources is unlikely to change, and it would be expected to intensify in the future.

The challenge for grassland managers is to operate within this environment or develop a strategy to capitalise from it. The objective in the interim is always the sustainable and profitable stewardship of the grassland resource, and opportunities do exist for this to occur through prudent management of inputs and the enterprises that harvest the resource. Productivity, under increasing climate variability which is constrained by soil and pasture resources (which is especially dependent on location and previous investments into production capacity) and its interaction with high land prices, will challenge the future viability of traditional agricultural enterprises. In combination such factors will impede entry to and expansion of traditional grassland based enterprises in the region.

Substantial opportunities do exist though, for cashed up investors to secure the last remaining high return/lower risk larger scale grazing properties in the region, especially in the higher rainfall/higher altitude regions. Such properties retain the additional advantage of potential future subdivisional development if the demand from non-traditional users of grasslands is maintained. The substantial risk to such a strategy is that political decisions may be made to constrain Australia’s diminishing capacity for food security without proper planning and


consideration of the multiple uses of grassland resources. This desire for food security would come at a cost to both regional communities and the personal wealth creation of the current cohort of grassland managers.

AcknowledgmentsA special thanks to Craig Poynter of the Spatial Data Analysis Network, Charles Sturt University, who compiled the spatial images of rainfall, land capability assessments and land use in the central Tablelands.

ReferencesBehrendt K (2005) Grazing Management and pasture

innovations: what’s best for your farming system? In ‘Proceeding of the 20th Annual Conference of the Grasslands Society of NSW’. pp. 69−74.

Behrendt K, Cacho O, Scott JM, Jones RE (2009) Bioeconomic analysis of fertiliser input costs on pasture resource management under climatic uncertainty. In “Proceedings of the AARES 53rd Annual Conference, Cairns’. (Australia: Australian Agricultural and Resource Economics Society)

Behrendt K, Stefanski A, Salmon EM (2000) Fine tuning the timing of lambing in spring: is it profitable? In ‘Proceedings of the 15th Annual Conference of the Grassland Society of NSW’. pp. 127−129.

Crofts FC (1989) Managing and developing native grass pastures for sustained production and profitability. In ‘Proceeedings of the 4th Annual Conference of the Grassland Society of NSW’. pp. 71−76.

Crofts FC (1997) Australian pasture production: The last 50 years. In Pasture Production and Management. pp. 1−16. (Eds JL Lovett, JM Scott). (Marrickville: Inkata Press)

Curtis K (2009) Recent changes in the Australian Sheep Industry. 15 (Ed DoAaF WA). Perth: Department of Agriculture and Food WA.

Dellow JJ, Wilson GC, King WM, Auld BA (2002) Occurrence of weeds in the perennial pasture zone of New South Wales. Plant Protection Quarterly 17, 12−16.

Emery KA (1986) Rural Land Capability Mapping. (Soil Conservation Service of NSW)

Garden DL, Dowling PM, Eddy DA, Nicol HI (2001) The influence of climate, soil, and management on the composition of native grass pastures on the central, southern, and Monaro tablelands of New South Wales. Australian Journal of Agricultural Research 52, 925−936.

Kemp D, Dowling P (1991) Species distribution within improved pastures over central N.S.W. in relation to rainfall and altitude. Australian Journal of Agricultural Research 42, 647−659.

Keys M, Clements B (2006) Management for Productive, Persistent and Profitable Native Pastures. In ‘NSW Grassland Society Newsletter’, Vol. 21, 9−11 Orange: (NSW Grassland Society)

Leech F, Keys M (Eds) (2000) The Grazier’s Guide to Pastures. (NSW Agriculture)

LPIA NSW (2010) Tablelands Grazing. In NSW Land Values: Blue Book. (NSW Land & Property Management Authority: Sydney)

Moore AD, Donnelly JR, Freer M (1997) GRAZPLAN: Decision Support Systems for Australian Grazing Enterprises. III. Pasture Growth and Soil Moisture Submodels, and GrassGro DSS. Agricultural Systems 55, 535−582.

Scott JM, Cacho O (2000) Modelling the long-term effects on farm net worth of investments in pasture fertilizer under constraints of family expenditure. Agricultural Systems 63, 195−209.

Sheng Y, Zhao S, Nossal K (2011) Productivity and farm size in Australian agriculture: reinvestigating the returns to scale. Australian Agricultural and Resource Economics Society 22.

Vere DT (1998) Investigating improved pasture productivity change on the New South Wales tablelands. Agricultural Economics 18, 63−74.

WRI (2005) The Economic Impact of Rural Subdivision and the Forest Industry with particular reference to the Central Tablelands region and the Oberon Shire of NSW. pp. 51. (Central Western Regional Development Board: Bathurst)

A proud sponsor of the 26th Annual Conference of The Grassland Society of NSW


Farming the grass curve in the context of changing opportunities in the Australian lamb market − a central Tablelands perspective

G.M. and G.J. Salmon“Ambleside”, Oberon, NSW 2787

Abstract: This paper examines the opportunities, threats and realities of three systems of prime lamb production suited to the central Tablelands (lamb breeding and finishing in the one operation; store lamb breeding and pasture-based lamb finishing). Traditional systems of prime lamb production were well matched to the feed curve on “Ambleside” and resulted in relatively high levels of feed use efficiency, probably in the range of 40−45%. In the past 25 years, we have focused on trialling, developing and adapting grazing systems that will lift pasture utilisation rates above a target of 50%, using tactical grazing management to maximise feed use efficiency. High levels of feed use efficiency, and hence productivity, results from working with the natural feed curve, not against it. The key message is to adapt to changing market and climatic conditions by being flexible in the choice of target markets

Key words: feed use efficiency, feed lambs, marketing flexibilityIntroductionThe market focused approach of the Australian prime lamb industry aimed at producing larger leaner lambs, which began during the 1990s, has created exciting market opportunities for lamb producers and has done much to improve the profitability of lamb enterprises. Twenty five years ago there was only one market specification for lambs which were sold only on the domestic market. However, profitability was low, threatening the long-term viability of prime lamb production.Today Australia has a much more sophisticated lamb market that services three market sectors, namely the domestic, export, and feeder markets. The challenge for lamb producers who wish to be both economically and environmentally sustainable is to target markets which are well matched to the production capabilities of their pasture resources.

By effectively ‘farming the grass curve’ producers can maximise the efficiency of pasture utilisation, increase kilograms of meat produced per hectare and lower unit costs of production. Moreover, grazing systems which match feed demand needed to reach target market specifications with the natural cycle of pasture growth, improve the sustainability and longevity of valuable pasture resources.

The reality for lamb producers on the central Tablelands of New South Wales (NSW) is that our short, but very abundant season of quality

perennial pasture growth and the apparent trend toward drier and less reliable autumns makes the choice of target markets of critical importance. While lamb production on the central Tablelands was once well matched to the period of greatest efficiency of pasture growth and utilisation in spring, the lengthening of total production time needed to produce larger leaner lambs has pushed the finishing period into late summer and autumn, when both pasture growth and feed use efficiency are in decline.In this paper, we will explore how we have adapted our grazing management to meet the challenges of changing consumer demand and climatic change while maintaining the economic, social and environmental sustainability of our prime lamb enterprise.It will examine the opportunities, threats and realities of three systems of prime lamb production suited to the central Tablelands, namely:• lamb breeding and finishing in the one

operation• storelambbreeding• pasturebasedlambfinishingSetting the sceneFor the past 25 years, we have operated a 770 ha property, “Ambleside” at Oberon, which has an average annual rainfall of 830 mm. The estimated total carrying capacity of “Ambleside” is 12,000 dry sheep equivalents (DSE). In 1997, we purchased a 100 ha irrigation block, “Warrego”, on the Fish River at O’Connell,


which was used for finishing lambs. “Warrego” has an estimated carrying capacity of 3000 DSE. We have recently sold this block. “Ambleside” maintains three main grazing enterprises: prime lamb production, weaner cattle production and a small stud Dorset flock to produce rams for our own use.Poor utilisation of Australian pastures is often seen as the major limiting factor to the productivity of grazing systems. Since her student days Gillian has recognised the opportunity to improve productivity by increasing pasture utilisation. Traditionally, pasture utilisation rates on eastern NSW grazing properties are generally low, between 20 and 40% (Alcock 2006). In the past 25 years, we have focused on trialling, developing and adapting grazing systems that will lift pasture utilisation rates above a target of 50%. Basically, we use tactical grazing management to maximise feed use efficiency.

Enterprise goalsIt follows that our main enterprise goals are to:• maximise productivity as measured by

kilograms of meat produced per hectare by using grazing systems that maximise feed use efficiency.

• sustainablygrazeperennialpasturespeciesby matching seasonal feed availability to livestock demand.

• targetenterprisesandmarkets thatmatchtheir pasture curve.

• minimisethecostofproductionbyusinglowcost grazing systems that target efficient use of labour and natural resources (particularly pasture).

Characteristics of “Ambleside’s” pasture curveFor the central Tablelands of NSW temperature rather than moisture is the limiting factor for pasture growth and animal production. On “Ambleside” the growth curve for improved perennial pastures is characterised by a sharp peak of lush spring growth (Figure 1). Far from being ‘a silent spring’, Oberon springs scream at graziers to be utilised for maximum production from livestock before pasture quality declines with the onset of summer.

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Figure 1. Estimated daily pasture growth for temperate grass and subterranean clover on the central Tablelands of NSW (Source: Meat & Livestock Australia 2008).

Traditional methods of farming the grass curveIn the 1980s, when we began our careers as lamb producers, the traditional system of lamb production was almost perfectly matched to the grass curve. Lambing was timed so that early lactation feed demand matched the onset of spring growth to make the best use of spring feed. Placing the highest grazing pressure during spring months maintained pastures in the vegetative stage to ensure high digestibility (>65% dry matter (DM) digestibility) and metabolisable energy contents of between 9−11 MJ/kg (Keys 1995) and a legume content of >30%. These factors contribute to maximum pasture use efficiency for weight gain of lambs. As Freer et al. (1997) showed, maximum weight gain in animals is also a function of the day of the year. At the latitudes of the central Tablelands (approx 33−35 degrees south) maximum efficiency occurs from early September through to December, but is lowest in autumn and early winter (Figure 2).

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Figure 2. Pasture use efficiency for weight gain as a function of month of the year at pasture metabolisable energy contents of 9 MJ/kg DM (—) and 12 MJ/kg DM (- - -) (Source: Freer et al. 1997).


Thus lambing in spring ticked all the boxes for maximising lamb growth rates of around 250 g/day so that lambs reached a marketable weight of 35 kg liveweight (16 kg carcass weight) with a fat score of 3−4 in 15−18 weeks. At stocking rates of approximately 7.2 ewes/ha and lambing percentages of 130% this equated to the production of 150.4 kg meat/ha.

The majority of the lamb drop was turned off by Christmas, before pasture quality and quantity declined. Once lambs were sold, breeding ewes could be grazed through late summer and autumn at high grazing pressures to keep herbage mass in the critical 800−2500 kg DM/ha window. This strategy encouraged both the development of grass tillers and the setting of clover seeds in the autumn months, factors which are critical to late winter and early spring pasture growth therefore helping to drive lamb growth rates in the following spring. The traditional autumn break allowed fresh pasture growth to be used to build ewe bodyweights prior to joining to ensure high lambing rates the following spring.

Economic realities of traditional prime lamb productionTraditional systems of prime lamb production on “Ambleside” were well matched to the feed curve and resulted in relatively high levels of feed use efficiency, probably in the range of 40−45%. However, the economic realities of lamb production during the 1980s meant that lamb enterprises were economically unsustainable.

Declining domestic consumption of lamb during the 1980s, due to negative consumer perceptions about the ‘fattiness’ and versatility of lamb lead to low farm gate prices and extreme price volatility, which meant that returns to producers were low, and often below the cost of production. In 1986, despite topping the market for lambs at a price of $26/lamb, we calculated the cost of production to be close to $28/lamb. Clearly, something had to change.

The 1990s … a decade of changeIn the 1990s the lamb industry, lead by its peak industry body now known as Meat & Livestock Australia, were successful in developing key export markets to the United States of America,

north Asia and the European Union. These markets demanded a larger leaner lamb than the domestic 16 kg carcass weight lamb. Since the 1990s, genetic improvements targeted at producing larger leaner lambs and improved grazing practices have lead to a steady rise in the average carcass weights of lambs produced in Australia (Figure 3).

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Figure 3. Change in average Australian lamb carcass weight from 1987−2008 (Source: ABARE 2009).

It is important to acknowledge the role that improvement to prime lamb genetics has made in achieving larger carcass weights. However, we are firm believers that changes to grazing management on “Ambleside” have been of equal importance. As Thatcher (1999) put it ‘While it is well recognised that the engine room for growth in the lamb industry in the past decade has been vastly improved genetics in the prime lamb flock, it is the feeding process that provides the fuel.’

In the period between 1989−2008, carcass weights for lambs produced from Ambleside have risen from 16 to 22.5 kg.

Implications of increased carcass weights on feed use efficiency on “Ambleside”Logically, producing a larger lamb carcass extends the production time for lambs well into the autumn period, which, as we have seen, is the period of lowest efficiency of pasture use for weight gain and, due to a succession of dry autumns, was also a period of insufficient growth of quality lamb finishing pasture. Producing lambs to meet market demand for ever increasing carcass weights became a real challenge on “Ambleside”.


Initially, our response to this challenge was three-fold:1. reducing ewe numbers (stocking rate)

to allow for increased feed demand of producing larger lambs.

2. sourcing terminal sire genetics that targeted higher growth for lambs.

3. growing fodder crops such as fodder rape to fill the autumn feed gap.

The reality of these strategies was that despite achieving a higher price for lambs, both productivity in terms of kg meat/ha and feed use efficiency fell. The reason was simple − we were working against the feed curve not with it. So while the economic sustainability of our lamb enterprise had improved, the sustainability of our pasture-use was under threat.

In 1997, the opportunity arose to purchase a 100 ha irrigation block on the Fish River at O’Connell capable of finishing up to 3000 lambs. This allowed us to separate our lamb enterprise into two distinct operations, breeding and finishing. The big advantage of weaning lambs off the Oberon block at 12−14 weeks and finishing them on irrigated pastures and lucerne, was that we could return to our traditional system of farming the grass curve at Oberon, while still realising the economic opportunities of higher prices for larger leaner lambs. By returning to a pattern of deferred grazing of lambing pastures in autumn, pasture growth in late winter and early spring significantly improved compared with the period of trying to breed and finish larger leaner lambs in the one operation.

The overriding advantage of a segregated breeding and finishing prime lamb production system on “Ambleside” and “Warrego” was that lambs reached marketable weights at an earlier age. Therefore, the amount of feed and water resources consumed per kilogram of meat produced was significantly reduced.

Specialised lamb finishing 2002−05Following the success of separating breeding and finishing operations into two distinct enterprises, particularly in terms of improved pasture use efficiency, we began to explore the opportunities of becoming specialised pasture lamb finishers.

In a traditional prime lamb enterprise, approximately 70% of pasture is utilised in maintenance of the breeding flock (Dickerson 1978). The three basic concepts behind our idea of specialised lamb finishing on pastures were to:• usethe70%ofpasturegrowthtraditionally

used to maintain breeding ewes to grow out lambs, thereby increasing the kilograms of marketable meat produced from the same pasture resource base.

• realise the genetic growth potential oflambs by optimising the use of high quality pastures, and

• improvetheefficiencyofpastureutilisationresulting in lower costs of production and hence improved profitability.

In 2002, with the assistance of Ashley White from the Department of Primary Industries, we used fodder budgeting and gross margin budgeting models to design a lamb finishing system to be used on 400 ha of “Ambleside”.Proplus, a fodder budgeting tool was used to calculate the number of lambs the finishing enterprise could support each month. Proplus calculated that for every lamb raised in traditional second cross breeding enterprise, four lambs could be finished using the same pasture resource base. Thus, while 2500 lambs were produced to larger leaner lamb weight of 20+ kg in the breeding enterprise, 10,000 lambs could be finished using the same pasture resources.In the model proposed by White et al. (2002), store lambs of known genetic potential would be purchased from early spring at liveweights of approximately 30 kg. These lambs are finished on high quality spring pastures at “Ambleside” with target growth rates of at least 200−250 g/day. At these growth rates lambs would be ready for the domestic market (45 kg liveweight) in less than eight weeks and will reach export market specifications of 47−50 kg in around ten weeks.Autumn remained the critical period for pasture management in the finishing model. To reduce environmental risks associated with erosion, and to promote tillering of grasses and seed set of legumes, fodder budgets should be managed to maintain more than 800 kg DM/ha through autumn. To achieve this, the finishing system was designed so that 90% of lambs were sold by February and only 10% carried through to the following autumn.


And so it was that in the spring of 2002 that we boldly and bravely purchased 10,000 lambs to test the finishing model. Lambs born in June−August were purchased from producers around Boroowa on the south west Slopes of NSW. This area was chosen because its pasture growth curve complemented the growth curve of the central Tablelands (Figure 4) and its proximity to Oberon minimised freight costs. Lambs were then rotationally grazed on perennial pastures with at least 30% legume and a digestibility of 75−80%. The overall goal of the finishing system was to make optimum use of spring pasture growth in order to make the best use of the window of opportunity for high weight gains in feeder lambs.

Threats to the finishing model – it is all about marginsThe biggest threats to the lamb finishing model are the marketing and financial risks. Managing the margin between the price received for the finished lamb and the cost of purchasing, transporting, feeding and selling the lamb is absolutely critical.

In brief, the White et al. (2002) model managed and planned for these risks by establishing strategic alliances with feeder lamb breeders and lamb processors, and securing forward contracts for a major proportion of lambs sold.

Realities of the lamb finishing modelIn the first two years of operation, the trial lamb finishing operation on “Ambleside” delivered the following positive outcomes:

• a50%increaseinkgmeat/hamarketed.• a 15% reduction in per kilogram cost of

production.• an improvement inpastureuse efficiency

from 45% in the breeding system to 57% in the finishing system.

• a35%increaseinprofitabilitybasedongrossmargin analysis.

A critical success factor in achieving these production targets was the use of rotational grazing at high stocking rates on small paddock sizes to increase feed use efficiency and maximise kg of meat /ha. At one stage we trialled the use of Technograzing, which is an intensive system of rotational grazing, before deciding that the most effective system was to rotationally graze 400 lambs on 8 ha paddocks.

Long-term realities of specialised lamb finishing systemsSince 2005 the increased demand for feeder lambs driven by feed lotters wishing to finish lambs on grain, significantly reduced the profitability and viability of pasture-based lamb finishing enterprises. Higher prices for feeder lambs reduced profit margins below $20/hd, a level that we believed was economically unsustainable. At current prices for feeder lambs, which are above $100/hd, the capital invested in purchasing lambs represents a very significant financial risk!!

Current opportunitiesIn the past two years, the lamb market has evolved to include specifications and accessible opportunities to sell feeder lambs. For us this has created the opportunity to return to the traditional system of lamb production by targeting the feeder market and selling store lambs at 40−45 kg liveweight. Under this system lambs are sold either at weaning and certainly prior to the autumn break. Given a good autumn break the option exists to finish lambs to domestic market specifications, thus giving the enterprise some marketing flexibility. The above average seasonal conditions of the past two autumns has created the opportunity to build ewe numbers by purchasing first-cross ewe lambs that have been grown out to joining weight of 45 kg and joined at 8−9 months of age.

0

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20

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40

50

60

70

80


Past

ure

Gro

wth

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e (k

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a/da

y)

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Figure 4. Estimated pasture growth curves for the central Tablelands (—) and south west Slopes (- - -) of NSW (Source: Meat & Livestock Australia 2008).


If stocking rates could return to traditional levels of 7.2 ewes/ha on the 400 ha used in the lamb finishing model, 9.36 lambs would be produced/ha or 187 kg meat/ha, with an estimated pasture utilisation of 45% (Table 1). Improvements to genetics and grazing management made in previous years are critical to achieving these targets. In 2011, store lamb prices achieved for lambs sold in January made this a very feasible option.

Threats to feeder lamb productionThe current value of the Australian dollar represents a threat to this level of profitability. The long-term economic sustainability of targeting the feeder market depends on receiving a good price for feeder lambs which is of course driven by supply and demand.

ConclusionsOur experiences suggest that achieving high levels of feed use efficiency, and hence productivity, results from working with the natural feed curve, not against it. The key message is to adapt to changing market and climatic conditions by being flexible in the choice of target markets. This ensures that feed demand is well matched to feed supply throughout the year. While finishing lambs under irrigation and specialised lamb finishing served their purpose, in what we now view as the transition years in the evolution of the modern market focused lamb industry, at current prices for feeder lambs they are not sustainable options for lamb producers on the central Tablelands of NSW.

Finishing lambs under irrigation achieved high growth rates and excellent productivity. However, rising energy costs and concerns around the use of water for irrigation compromises the economic sustainability of this

enterprise. Gillian is conflicted by using water resources for producing meat. It is more efficient to use water for vegetable crops which have higher productivity/megalitre of water used.

The economic realities of market volatility, which lead to reduced and uncertain margins for specialised lamb finishing in recent years, and the significant risk factors involved, compromise the advantages this system has in improving feed use efficiency and kg meat produced/ha. At current prices for feeder lambs, a return to the traditional model of lamb production offers the opportunity for lamb producers to effectively farm the grass curve. Time will tell how long this opportunity will remain.

ReferencesABARE (2009) Australian supply of mutton and lamb.

Australia Commodity Statistics 2009 http://www.abare.gov.au/publications-htm/dataAlcock D (2006) Using grazing systems modelling to asses

economic, production and environmental risks to aid in selecting appropriate stocking rates. Australian Journal of Environmental Agriculture 46, 841−844.

Dickerson GE (1978) Animal Size and Efficiency Basic Concepts. Animal Production 27, 367−379.

Freer M, Moore AD, Donnelly JR (1997) GRAZPLAN Decision Support Systems for Australian Grazing Enterprise – II. The Animal Biology Model for Feed Intake, Production and Reproduction and Grazfeed DSS. Agricultural Systems 47, 175−198.

Keys M (1995) Management of Profitable and Sustainable Pastures: A Field Guide. Prime Pasture Program. (NSW Agriculture: NSW)

Meat & Livestock Australia (2008) Making More From Sheep A sheep producers manual. (Meat & Livestock Australia, NSW.)

Thatcher L (1999) ‘Care Needed in Feeding Lambs’ Australian Farm Journal, August, 91−94.

White AK, Salmon GJ, Salmon GM (2002) Pasture Based Lamb Finishing Case Study. Proceedings of the Australian Society of Animal Production 24, 261−264.

Table 1. The estimated key performance data of the three lamb producing systems on “Ambleside”.

Enterprise Stocking rate (DSE/ha) Estimated meat production (kg meat/ha/yr)

Estimated pasture utilisation (%)

Traditional 16 kg lamb 15.8 150.4 40Breeding/finishing producing 22 kg lamb 9.7 128.7 <40

Lamb finishing 15 225 57Feeder lamb 18 kg lamb 15.8 187 45

IN THE CENTRAL WEST

The Central West Catchment Management Authority (CMA) is pleased to be a major sponsor of the 2011 Grassland Society of NSW Annual Conference.

For the interest of attendees, we have recently released a series of guides on current best practice for:

• pasture management

• native grasses

• soil health

• no-tillage farming

• native vegetation management

• riparian management

Practical, relevant and useful information is available to help you make important management decisions on your land.

To find out more and download your copy, visit www.cw.cma.nsw.gov.au.


Developing livestock preventive medicine programs with grassland farmers

B.R. Watt

Tablelands Livestock Health and Pest Authority, Bathurst, NSW 2795; [email protected]

Abstract: Examples of some diseases (internal parasites in cattle; selenium deficiency; cobalt (and therefore vitamin B12) deficiency; pestivirus in cattle and lead poisoning) are used to illustrate how a stock manager, in consultation with an animal health adviser, might design a livestock preventive health program.

Key words: internal parasites, selenium deficiency, cobalt deficiency, lead poisoning, theileria

IntroductionAnimal health is an important component of running a productive grazing business. In this paper, I will use examples of some diseases to illustrate how a stock manager, in consultation with an animal health adviser, might design a livestock preventive health program.

Assessing animal health threatsSome livestock diseases cause a predictable production loss if untreated on central Tablelands and Slopes grazing properties. Two examples are internal parasites (in both sheep and cattle) and selenium deficiency in Merino weaners. An important component of developing a livestock health program for these diseases is an examination of the cost/benefit of preventing them.

However, some diseases such as hypomagne–saemia in cattle and clostridial diseases in both cattle and sheep simply cause sudden death less predictably and so the livestock owner needs to examine the risk of these diseases. The two components of most risk assessments are the chance of occurrence (of a disease in this instance) and the potential impact of that disease should it occur.

In the analysis of animal health issues on an individual property, I also attempt to ascertain a farmer’s own attitude to risk and the likely cost-benefit of an action. In any advice to livestock producers on animal health programs, I also consider animal welfare, the broader interests of our livestock industries and the impact of a

problem or disease on the community and our consumers and trading partners.

What are the most important threats to the health of grazing livestock?There have been several attempts at quantifying the cost of various livestock diseases on the national economy. Meat & Livestock Australia commissioned the most recent study (Sackett and Holmes 2006). From our collective experience and research and from this report, the main livestock health problems on the central Tablelands of New South Wales (NSW) are listed below.

For catt le producers , gastrointest inal parasitism is a major threat to the health of young cattle, while in good seasons, bloat and hypomagnesaemia emerge as significant threats. Also, liver fluke are prevalent especially on the eastern Tablelands and represent a significant threat to young cattle if uncontrolled. Much of the Tablelands is selenium deficient and small areas are cobalt deficient. Pestivirus presents a threat to herds of cattle that are unprotected, either by vaccination or prior exposure to the virus (Watt 2007). Theileria is a cattle disease new to the Tablelands and capable of causing substantial mortality in mature cows (Bailey 2011).

For sheep producers, gastrointestinal parasites are the major threat. Widespread drench resistance exacerbates this problem. Fly strike continues to cause problems to the sheep industry and the need to consider alternatives to mulesing represents an ongoing challenge (Sackett and Holmes 2006). Also, lice infestation remains an issue in sheep. We know that about



20% of Tablelands flocks are lice infested and about another 10% have a light subclinical infestation (Watt and Eppleston 2010).

In this paper, I will discuss my approach to advising farmers on livestock health programs by considering a few examples.

Example 1. Internal parasites in cattleSmeal et al. (1981) examined the effect of gastrointestinal nematodes in young beef cattle on the northern, central and southern Tablelands and the north Coast of NSW. In his study, conducted from 1965 to 1970, he found that young cattle drenched monthly with thiabendazole gained up to 23.9 kg more weight than undrenched cattle by 16 months of age. This response varied considerably with year and location. However, Smeal’s study risked underestimating the cost of gastrointestinal parasitism in cattle as his choice of anthelmintics at that time was limited. He used thiabendazole, which is both short acting, providing no protection against re-infestation and is of limited efficacy especially against Ostertagia larvae in arrested development in the abomasal wall. Smeal acknowledged these limitations and later concluded that effective internal parasite control, through a combination of strategic grazing management and anthelmintics, could increase liveweight gains by 30–60 kg/head 9–12 months after weaning (Smeal 1991).

Jeff Eppleston and I decided to investigate the cost of internal parasites in young cattle on the central Tablelands with the benefit of a new anthelmintic, moxidectin. Injectible moxidectin (Cydectin, Fort Dodge) has the advantage of sustained action, so protecting the suppression treated portion of the mob from re-infestation and is highly effective against gastrointestinal parasites of cattle including against all stages of Ostertagia. We treated 20 heifers in six mobs of at least 100 heifers every three months from weaning for the next 12 months. When we compared the liveweight gains of the suppression treated portion of the mob with the completely untreated heifers on one property, we found that the treated calves weighed 50 kg more than those that were untreated. They also weighed on

average 28 kg more than calves drenched using the normal program of the individual farmers (Watt and Eppleston 2011a).

It is cost effective to control internal parasites in young cattle with a return in the order of 10:1. Unfortunately however, the means available for us to monitor internal parasitism in cattle (worm egg counts and blood pepsinogen levels) are of limited value. Although further research into the control of internal parasites in young cattle is required, for spring calving herds, we recommend that calves are drenched at weaning in the autumn (with an effective drench and placing onto ‘clean’ pastures if possible), with follow up drenches in mid winter and the following spring.

Example 2. Selenium deficiencyWe know from surveys that selenium deficiency is widespread on the Tablelands (e.g. Watt 2007). We also know from our own research and that conducted elsewhere that young Merino sheep are likely to respond to selenium supplementation with improved bodyweight (up to 2 kg/hd) improved fleece quality and lower parasite status (Caple et al. 1980; Celi et al. 2010). As an animal health adviser, I do not hesitate to recommend that producers who run Merinos with low levels of blood selenium (as evidenced by glutathione peroxidase levels) will get a satisfactory return on an investment in selenium supplementation.

However, it is difficult to prove an economic response to selenium in cattle. In a trial that Jeff Eppleston and I conducted recently, selenium deficient heifers did not grow faster when treated with long acting barium selenate (Deposel, Novartis) by injection (Watt and Eppleston 2011b). Yet I have seen a couple of mobs of young cattle with ill thrift, rough coats and diarrhoea for which the only problem detected was low blood selenium levels (Watt 2011). Others have reported infertility in selenium deficient cows (Radostits et al. 2007).

In the face of this somewhat unconvincing evidence, I recommend that cattle producers in selenium-deficient areas should supplement with selenium. My justification is that selenium


is involved in a wide range of functions, including the immune system and so the consequences of deficiency are unpredictable. Selenium supplementation with long acting injections is now easy, safe (as long as the correct dose is given), inexpensive and long lasting. In a grazing system, many components and in particular price and rainfall are beyond our control. However, the selenium status of our stock is under our control and supplementation removes the risk of problems associated with deficiency.

Example 3. Cobalt (and therefore vitamin B12) deficiencySome commercial interests have argued that vitamin B12 supplementation is beneficial across wide areas of NSW. However, our surveys of sheep and cattle indicate that blood vitamin B12 levels are adequate across most of the Tablelands and Slopes, apart from a small area of granite-derived soils east of Bathurst. In collaboration with sheep producer Greg Emms, Jeff Eppleston and I investigated the response to vitamin B12 in lambs treated at marking on Greg’s property near Lyndhurst. We did not find a response to vitamin B12 supplementation and blood B12 levels were normal (Watt et al. 2009).

I can see no rationale for supplementing livestock with vitamin B12 on the central Tablelands or Slopes except on those clearly defined areas in which blood tests demonstrate cobalt deficiency.

Example 4. Pestivirus in cattle Several surveys demonstrate that pestivirus occurs in about 90% of beef cattle herds across Australia (e.g. Taylor et al. 2006). A serological survey found a similar prevalence in cattle on the NSW central Tablelands (Watt 2008). In my experience, losses are often imperceptible on properties where the disease is endemic. However, on properties (or herds within properties) without exposure to pestivirus, losses can be substantial. I therefore consider it important to establish the pestivirus status of large herds before considering a control program. For small herds, it is usually cheaper

to vaccinate as a precaution than to determine the pestivirus status of the herd.

The pestivirus status of a herd can be determined by blood testing about eight cattle from three different age groups. In herds with substantial exposure, as measured by blood antibody levels to pestivirus, a vaccination program is unnecessary. However, cattle producers need to be aware that pestivirus can die out in a herd, leaving younger cattle susceptible. In herds with moderate levels of exposure, the livestock manager should consider a vaccination program depending on the level of exposure and his enterprise and attitude to risk.

Herds (or mobs within herds) with little or no exposure to pestivirus run the risk of a disastrous incursion of the virus at some stage. These herds should either adopt a vaccination program or adopt strict biosecurity measures to prevent the introduction of pestivirus. Unfortunately however, pestivirus vaccination is relatively expensive and has therefore not been as widely adopted as might be desirable. For producers reluctant to profile the entire herd, I advise that they at least test their heifers well before joining. Similarly, for producers reluctant to adopt a complete vaccination program, I suggest that they ‘hedge their bets’ by at least vaccinating heifers twice before the first joining.

Example 5. Lead poisoningLead intoxication is the most common form of poisoning of cattle worldwide (Osweiler et al. 1973; Humphreys 1979; Seawright 1982; Jubb et al. 1992; Sharpe et al. 2004). Our Tablelands regional animal health team, which includes LHPA staff and private veterinarians, diagnose one to two cases each year. On any one farm, the risk of exposure is low, but the potential impact on a farm can be high with substantial mortalities and constraints on selling lead exposed cattle (Watt 2006). However, if a case of lead poisoning goes undetected only to be discovered by subsequent residue testing, the ramifications for the industry could be enormous. Domestic and international trade could be threatened and consumer confidence undermined.


Livestock producers need to act to reduce the risk of lead poisoning. These measures are simple and inexpensive. They involve denying livestock access to lead. This means collecting and disposing of old batteries, lead paint and sump oil. These actions are therefore highly cost-effective when viewed against the risks posed by lead poisoning.

ConclusionsOf the wide range of diseases that pose a threat to the livestock enterprises of central Tablelands and Slopes graziers, some are amenable to regional control recommendations. Internal parasites in cattle and, to a lesser extent sheep, are examples. In other cases however, knowledge of the disease status or risk needs to be determined for an individual property. I have used a range of examples to discuss how we might determine an appropriate animal health program for a range of diseases threatening the health of our livestock.

ReferencesBailey G (2011) Benign bovine theileriosis – a questionnaire

of 64 affected properties. In ‘Proceedings of the 93rd Conference of the Association of District Veterinarians, Dubbo’. http://www.flockandherd.net.au/cattle/reader/benign%20bovine%20theileriosis.htm

Caple IW, Andrewartha KA, Edwards SJA, Halpin C (1980) An examination of the selenium nutrition of sheep in Victoria. Australian Veterinary Journal 56, 160–167.

Celi P, Eppleston J, Armstrong A, Watt BR (2010) Selenium supplementation increases wool growth and reduces faecal egg counts of merino weaners in a selenium-deficient area. Animal Production Science 50, 688–692.

Humphreys DJ (1979) Trends in veterinary pharmacology and toxicology. In ‘Proceedings of the first European Congress, Zeist’.

Jubb KVF, Kennedy PC and Palmer N. (1992). Pathology of Domestic Animals, Fourth Edition. p. 163.

Osweiler GD, Buck B, Lloyd WE (1973) Epidemiology of lead poisoning in cattle – a five-year study in Iowa. Clinical Toxicology 6(3), 367–376.

Radostits OM, Gay CC, Hinchcliff KW, Constable P (2007) Veterinary Medicine, Tenth Edition. p. 1740.

Sackett D, Holmes P (2006) Assessing the economic cost of endemic disease on the profitability of Australian beef cattle and sheep producers. Final Report AHW.087. (MLA: North Sydney)

Seawright AA (1982) Animal Health in Australia, Vol. 2 Chemical and Plant Poisons. (Australian Government Publishing Service: Canberra)

Smeal M, Nicholls P, Webb R, Hotson, I, Doughty F, Harding W (1981) The effect of anthelmintic treatments on growth of beef cattle in NSW. Australian Journal of Agricultural Research 32, 813–823.

Smeal MG (1995) Parasites of Cattle. The University of Sydney Post Graduate Foundation in Veterinary Science, Sydney South.

Taylor LF, Black PF, Pitt DJ, Mackenzie AR, Johnson SJ, Rodwell BJ (2006) A seroepidemiological study of bovine pestivirus in Queensland beef and dairy herds conducted in 1994/95. Australian Veterinary Journal 14(5), 163–168.

Watt BR (2006) Lead Poisoning in Cattle. In ‘Proceedings of the Australian Cattle Veterinarian’s Conference, Port Macquarie’. p. 102–104.

Watt BR (2007) A Serological and Trace Mineral survey of Beef Heifers in Central NSW. In ‘Proceedings of the Australian Cattle Veterinarian’s Conference, Townsville’.

Watt BR (2008) Pestivirus Prevalence and Management in the Central Tablelands. In ‘Proceedings of the Conference of the Association of District Veterinarians. Griffith’. www.flockandherd.net.au/edition/conference_2008.htm

Watt BR, Eppleston J, Emms G (2009) Treatment with Vitamin B12 did not improve growth of first cross lambs in a central tablelands flock. Skirting the Issues. The Official Newsletter of the Australian Sheep Veterinarians, autumn edition. p. 12.

Watt BR, Eppleston J (2010) Sheep Body Lice: An Increasing problem in Australia? In ‘Proceedings of the 3rd AVA/NZVA Pan Pacific Veterinary Conference, Brisbane’.

Watt BR(2011) Selenium deficiency in weaned Hereford calves. In ‘Proceedings of the 93rd Conference of the Association of District Veterinarian. Dubbo’. p. 181.

Watt BR, Eppleston J (2011a) The cost of internal parasites in young cattle on the central tablelands of NSW. In ‘Proceedings of the Australian Veterinary Association Annual Conference, Adelaide’.

Watt BR, Eppleston J (2011b) Selenium nutrition of sheep and cattle In ‘Proceedings of the 93rd Conference of the Association of District Veterinarians’, Dubbo’. p. 176.

http://www.flockandherd.net.au/cattle/reader/benign%20bovine%20theileriosis.htm

http://www.flockandherd.net.au/cattle/reader/benign%20bovine%20theileriosis.htm

http://www.ncbi.nlm.nih.gov/pubmed?term=%22Taylor%20LF%22%5BAuthor%5D

http://www.ncbi.nlm.nih.gov/pubmed?term=%22Black%20PF%22%5BAuthor%5D

http://www.ncbi.nlm.nih.gov/pubmed?term=%22Pitt%20DJ%22%5BAuthor%5D

http://www.ncbi.nlm.nih.gov/pubmed?term=%22Mackenzie%20AR%22%5BAuthor%5D

http://www.ncbi.nlm.nih.gov/pubmed?term=%22Johnson%20SJ%22%5BAuthor%5D

http://www.ncbi.nlm.nih.gov/pubmed?term=%22Rodwell%20BJ%22%5BAuthor%5D

http://www.flockandherd.net.au/edition/conference_2008.htm

http://www.flockandherd.net.au/edition/conference_2008.htm


Performance for profitM. Ryan

“Kilcooly”, Rydal, NSW 2790; [email protected]

Abstract: “Kilcooly” is a 700 ha grazing operation in the central Tablelands, NSW between Oberon and Lithgow (850–1000 m), with about 600 ha being pasture improved and regularly fertilised. This paper describes how they address the winter feed gap problem in their cattle enterprises and the positive effects it has on their beef cattle operations.

Key words: Merino ewes, Angus cattle, winter feed, protein and energy supplementation

We run a 700 ha grazing operation in the central Tablelands between Oberon and Lithgow, New South Wales. It is undulating to steep country with a light granite soil and an elevation of 850–1000 m. Approximately 600 ha are pasture improved and regularly fertilised. The remainder is native pasture and timber.

View across some of the paddocks on “Kilcooly”.

We run fine wool Merino ewes joined to terminal sires to produce a first-cross fat lamb and a self-replacing herd of Angus cattle. The best of our Angus cows are joined to Angus bulls to produce replacement heifers and feeder steers. Some older and lower performing cows are joined to Charolais sires to produce domestic or trade vealers sold at 9–10 months straight-off their mothers.

All cows calve in August–September. Angus calves are yard weaned at 5–6 months and the cows are then bulked up into larger mobs. Weaners graze the paddocks first then the cows follow behind them. This grazing strategy achieves several objectives:

1. Weaners have the best of the available feed so they continue to grow and gain weight.

2. More paddocks can be rested to grow feed for the coming winter.

3. With the dry cows we can apply more grazing pressure to the paddocks that need it.

Mob of Angus cows.

Some paddocks, particularly in a good season like 2010–11, can become grass dominant. If excess plant growth is not removed in the autumn, subterranean clover does not receive sufficient sunlight and moisture to survive. We need to encourage our legumes so we are in effect manipulating plant species simply by the way we graze the paddocks.

After weaners have been taken out of a paddock and before cow have been put in.


Paddock after the cows have been removed.

We monitor the condition score of our cows. Any that are in danger of falling below 3 score, we move onto better feed. The cows only have available to them poorer quality feed as the weaners have had the best of the paddock. Some cows will lose weight i.e.: –1. Cows that weaned a heavier calf than the

average and are in lighter condition at weaning time.

2. Heavily pregnant cows.3. Younger cows (under 4 years-of-age) still

trying to grow and cut teeth.4. Poorer performing cows.

We do not drench our mature cows. Young cows are drenched up to 3 years-of-age then we try to encourage their natural immunity to internal parasites.

In our part of the world 70–75% of the feed we grow occurs in the three months of the year – October–December. We seem to always face a winter feed shortage from mid July–September (Figure 1) so fodder budgeting is an important part of our management. To help address the feed shortage we drift our calved cows from their mob to an adjoining paddock with more feed. Thus saving the pasture for when it is most needed and rewarding the more fertile cows that calve early.Generally, over winter, our weaners gained around 250–300 g/day. We were not too concerned about their performance. We just waited for the spring flush and compensatory gain. We now believe this was wasting precious time. In the early 1990s, we changed our

management of weaners over the winter period. We were keen to capitalise on what seemed to be a price premium for feeder steers from late July to early September (Figure 2). We needed our steers to be >400 kg at 12–13 months-of-age to qualify for this price premium. We also want our heifers, or as many as possible, to be joining weight by September. We join our heifers three weeks before the main herd. The reasons for this are: –1. We can better utilise our bulls that are below

average for birth weight but above average for growth and carcase traits. These bulls are joined to the heifers for three weeks then they are removed and joined to the main heard. A backup bull replaces them for a further three weeks.

2. Calving heifers three weeks before the herd gives us more time to supervise their calving. As they calve we ear tag the calves with our management tag (recording the dam’s number and the sire). We then move them to an adjoining paddock with better feed. Only in-calf heifers remain in the calving paddock. This simplifies things and prevents potential mis-mothering.

3. As a rule, first calving heifers wean a lighter calf than mature cows. Calving earlier gives the heifer’s calf a better chance to be of similar weight to the mature cow’s calf. The more animals we have of similar weight at marketing time, the better – more to select from and cheaper transport costs. Each year there will be some steer weaners from these heifers sold with the first feeder steers.

Ten month old Angus weaners steers averaging 310 kg.


4. Calving heifers earlier gives them an extra three weeks recovery before being rejoined ‘in-sync’ with the main herd.

To achieve this we needed to increase the performance of our weaners over winter. Our frost-affected winter pastures were sadly lacking in protein and energy. Cropping was not considered an option because of our already established pastures and the topography. So we tried to secure a protein and energy source that will most economically do the job. We have used silage, grain and protein meal. We are mindful of the aim to supplement the weaner’s requirements, but not to completely replace them and so protein meal is a good option. When we calculated the gross margins for the feeding of the weaners the profitability was marginal at best. Weaners consume about 1.5–2 kg/head/day costing about 50 cents/head/day. They gained an extra 200–250 g/head/day so it was about breaking even.

However, the positive influence on performance and profitability to our beef cattle operation was another story;

1. Firstly our better steers are up to feedlot entry weight by late August early September (in an average season). Hopefully, catching any price premium that may be available. Regardless, they are out the gate and gone sooner leaving more feed available for the remaining cattle.

2. The remaining weaners are heavier, healthier and much better equipped to more efficiently utilise the spring pasture growth. Making them saleable much sooner.

3. Our heifers are up to the joining weight earlier. Those that are pregnancy tested empty are heavier and return more at point of sale. Those that are pregnant are closer to their mature weight at calving (which I believe helps their conception rate at the next joining).

4. Having sold the weaners earlier more feed is available for the cows and calves.

5. Last, but by no means least – surely our objective to produce high quality beef is enhanced by producing animals that have never had a set back in their lives.


Figure 2. Weekly feeder steer price from 2003 to 2011 and the average over this period.

Feeder steer price

100.0

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Figure 1. Pasture growth curves in comparison to livestock requirements on “Kilcooly”.


Pseudo-science: a threat to agriculture?D.C. Edmeades

agKnowledge Ltd, PO Box 9147, Hamilton, 3240, New Zealand [email protected]

‘On what principle is it that when we see nothing but improvement behind us, we are to expect nothing but deterioration before us.’

Thomas Macaulay 1830

Abstract: The case for agricultural science is asserted, but in the context that science is under threat in contemporary society because of the adoption of post-modern philosophies which give credibility to pseudo-science and give rise to what is now being described as Post-Normal Science. The author examines the question − Is there a legitimate argument to take to science managers, scientists, politicians and society to say pseudo-science is dangerous and should not be tolerated? It is concluded that science must be asserted and it must regain its proper moral high ground in society. To achieve this there must be changes to science policy and to how science is managed. Science, at least government (publicly) funded science, must be returned to its normative function.

Key words: pseudo-science, publicly funded science, organic farming, scientific evidence

IntroductionIn 2010, the United Nations estimated that by 2050 the world population will be about 9 billion. The world will therefore need to produce more food by increasing the area of land under cultivation and/or by increasing yields per unit area. The case has been well made elsewhere (Edmeades1 et al. 2010) that to achieve this ‘requires a sharp boost in research investment in plant agriculture from public and private sources, accompanied by facilitating policies’. It is this last point that I wish to expand.

In this paper, the case for agricultural science will be asserted again, but in the context that science is under threat in contemporary society because of the adoption of post-modern philosophies which give credibility to pseudo-science and give rise to what is now being described as Post-Normal Science.

The importance of agricultural scienceThe real value of science is best observed by looking backwards (Edmeades 2009). For example, despite major arguments at the time, we all now accept the evidence that the earth

is not flat, that the sun is at the centre of our solar system and that solid matter is made up of particles. The same perspective makes a strong case for agricultural research.

We are on average better fed, healthier and wealthier than ever before (Figure 1). According to Havlin et al. (1999), this is a consequence of discovering and harnessing new sources of energy and, especially since the 1950s, the application of science (Figure 2). The same conclusion emerges from the longest running experiment in soil science (Figure 3). As a consequence of improved plant genetics, coupled with the use of insecticides and pesticides, the yield of wheat, as measured in this experiment,

1 Not to be confused with the author.

Figure 1. Life expectancy through the ages. (http://filipspagnoli.wordpress.com/2009/09/29/human-rights-facts-148-life-expectancy-throughout-history/)

Life Expectancy through the Ages

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Figure 3. Wheat yield over time from Broadbalk, Rothamsted (Refer Edmeades 2003).

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has increased ten-fold from about 1 tonne/ha/yr to 10 tonnes/ha over a period of 150 years. The so-called Green Revolution which began in the 1960s, and without which many people would have starved, is a more contemporary example of the success of science and technology.

Of course the incremental increases in productivity due to science may become harder and harder to achieve (Edmeades et al. 2010) but, as they noted, there are still significant differences between actual farm production and that possible under controlled research

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Figure 4. Changes in farm yield and potential yield over time for wheat in Mexico (from Edmeades et al. 2010).

failures occurred they were a consequence of disobedience to Gods laws (Table 1). The Age of Reason emerged out of this gloom with the development of what we now call the scientific method – truth was that revealed by the application of logic and reason to the empirical evidence. Science became the authority. The industrial revolution was a consequence, and as indicated above, the progress made by society, at least western society, was astounding.

But confidence in science and its products – technology – began to be questioned after two world wars and the development of the atomic bomb. Science, while not the cause, was seen as part of ‘the problem’ – there must be, some argued, a better way forward for society. This led to the philosophical movement called post-modernism which sets aside evidence as the authority and asserts that the ‘truth’ is what you believe – if you believe it, then it is your ‘truth’ – the age of individualism had arrived. Importantly, in this setting, all opinions are to be given equal authority; irrespective of where the evidence lay.

The political expression of post-modernism is found in what is called laizie faire politics – less government is good government! Accordingly, it was argued that it is not the government’s role to

conditions (e.g. Figure 4). Thus, there are two pathways to increase food production – through more science and improved technology transfer. There are, however, clouds of doubt which threaten these opportunities.

Post-modern philosophy

Respect for science is being eroded and to understand why, we need to understand the philosophical settings of modern society. Simplistically2, in the Dark Ages the Church was the authority because only the priests could, via prayer, find the truth as revealed by God. If

2 To avoid being accused of pseudo-science myself (see discussion later) I must declare that I have no training in philosophy and do not keep up to date with the relevant literature. What I have recorded here is my personal understanding based on limited reading. If there are errors of fact, logic or interpretation I would be most grateful to have them corrected.

Table 1 Authority and belief through time (modified from Roche and Edmeades 2005).

Period Truth Authority Attitude Example

Dark Ages Revealed by God though prayer.

Church Thou shalt obey the laws of God.

Pray for a good harvest. Your animals died because you sinned.

Age of Reason Revealed by reason based on the evidence

Science What is the evidence and what can logically be deduced from the evidence.

Liquid fertiliser are ineffective. Albrecht’s ratio theory is flawed.

Post-modernism If you believe it is true Individual Science is the reason for all our problems. A new way must be found.

Homeopathy works because I believe it. Organic farming is better for the environment.


set or impose standards – that was now to be left to society and its representatives, the professional and industrial bodies – self-regulation became the mantra. A relevant agricultural example in New Zealand is the Fertiliser Act 1960 which was repealed in 1997 as part of a package of reforms. It was replaced by the Federated Farmers ‘FertMark Scheme’. This is a voluntary scheme and deals only with ‘truth of labelling’. As a matter of policy the agronomic efficacy of products is not considered. Needless to say it is completely ineffective at protecting its farmer members from products marketed on the basis of pseudo-science. Presently in New Zealand, it is quite legal to sell almost anything and call it a fertiliser as shown by one of the examples discussed later.

Post-modernism has progressed to what is now being called ‘Post-Normal Science’. This holds that science is subservient to the story that must be told. The role of science is no longer about discovering new ‘truth’, but supporting the ‘story’ which is perceived to be the truth. This gives rise to the notion of ‘noble-cause science’, which allows scientists to ignore contrary evidence, or worse, manipulate the evidence, if the cause is noble. There is evidence of this in the current climate change debate as will also be discussed later.

It is in this manner that post-modernism has provided a philosophical framework that legitimises pseudo-science. This applies especially to one of its ’success’ stories – environmentalism. Indeed, Geering (2002) a well respected New Zealand theologian, has suggested that environmentalism is logically the new ‘God’. We have gone, it appears, full circle from the Gods of the Dark Ages to the Gods of environmentalism3.

Psuedo-science Post-modern philosophy not only provides a fertile breeding ground for pseudo- (false, fake) science, but it also undermines the importance of science. How else do we explain, for example, at a time in human history which owes so much to science, that alternative ‘medicines’, for which no proof of efficacy is required, sit on the same shelves as real medicines, which must meet strict evidentiary requirements? How is it that a recent business award in New Zealand went to a person whose company offers farmers homeopathic remedies for their animals? And how is it that a leading New Zealand farming magazine can run this ‘success story’ with not a comment to warn farmers that homeopathy is pseudo-science? All of these questions are, in themselves, evidence of how invasive pseudo-science has become in modern society. With the help of Coker (2001) it is instructive to look at some examples of pseudo-science to explore how it operates.

Psuedo-science is anti-scienceAt its heart pseudo-science is anti-science because it can only prevail if science is undermined and belittled. Here are some examples related to agricultural science:

‘Our chemical experiment (i.e. the past 80 years of farming) using high leaching fertilisers has effectively stripped the majority of the minerals from the soil ………… these serious deficiencies are arguably the most urgent problem we need to address in the coming century ‘ Nutritech Solutions Pty Ltd

‘Past agricultural practices have resulted in the demineralisation of our farming soils and the chemical sterilisation of the soil biology that would normally deliver these minerals to the plants’. Abron Living Soil Solutions Ltd

Given the empirical evidence in Figures 1 to 4 these generalised statements are false. They also demonstrate some of the other characteristics of pseudo-science – science words, or words that sound scientific, are used, even though at the same time they condemn agricultural science as the problem! And this is another reason why pseudo-science is so pernicious. A competent scientist aware of the evidence would not be duped, but what about the layman, or indeed

3 A clear distinction is required. We must find ways of using our resources – soil, water, air, energy carefully and efficiently and I have no doubt we can and will. After all, the hallmark of modern man is success (refer to Figures. 1–4). But this will only be achieved by the application of the science method based on evidence. This approach is to be contrasted with ‘environmentalism’ based on a blind faith that we are ruining the planet and we must repent and serve the new God of ‘environmentalism’.


the technically illiterate journalist looking for an alarmist story that will sell?

Psuedo-science uses fear-mongering Pseudo-science plays on people’s emotions by implying that doomsday is imminent. Here are two examples related to agriculture:

‘We now have the lowest nutrient density in our food than we have ever had in out history and we can relate that to what is happening health-wise’ Dr Christine Jones‘Millions of acres of soil that sustained the worlds feed supply are under assault. For decades farmers have learned to use large quantities of fossil fuels to produce crops. But these synthetic additives have pushed our soils, our environment and our health to the limit.’ Dr Arden Anderson

Once again the evidence about human longevity and soil productivity, discussed earlier are alone enough to negate these comments and we are entitled to ask Macaulay’s question posed at the beginning of this paper: ‘On what principle is it that when we see nothing but improvement behind us, we are to expect nothing but deterioration before us?’

Psuedo-science uses conspiracy theories ‘…..why does conventional agriculture… sanction and perpetuate the obscuring and demoting of William Albrecht’s landmark work in soil science, as well as his forced early retirement, in order to secure substantial grants from major chemical companies…’ Dr Arden Anderson

Psuedo-science claims wisdom from the past now overlooked

‘Biological agriculture is a new paradigm, a rekindling and modernization of ancient wisdom’. Dr Arden Anderson

Psuedo-science is too good to be true ‘Most of the diseases are nutritionally related so that things like cancer, cardiovascular disease, diabetes – all these things are related to the fact that we do not have the trace elements in our bodies’. Dr Christine Jones

Many claims made by those who practice pseudo-science are simple nonsense. Consider for a moment that cancer, cardiovascular disease and diabetes could be cured by the administration of a cocktail of trace elements! As my colleague

Dr Roche would say, ‘If it sounds too good to be true it probably is!’

Psuedo-science calls for a new way of thinking!

‘We need a fundamental redesign of agriculture and the whole approach to food and food production’ Dr Christine Jones‘Science needs the freedom to think outside the square by incorporating intuition with intellect to create new opportunities and new business’ Mr J K Morris, Agrissentials Ltd

Why, given the evidence showing the success of science and technology is it necessary for a ‘fundamental’ change? I agree that agricultural science faces a large challenge as it attempts to feed a world of 9 billion people and at the same time reduce our environmental footprint, but this does not imply that agricultural science is flawed in some fundamental way. And the meaning behind Mr Morris’s statement above becomes clearer when it is realised that his New Zealand company, Agrissentials Ltd, sells ground basalt rock and claims it is a ‘fertiliser’ – the old science says it is ineffective, but the new intuitive – if you believe it ‘science’ – will claim its positive merits!

In effect, these people want to change the rules of science so that their ‘new science’ will endorse or embrace their opinions or products.

‘Scientists’ practice pseudo-scienceThe boundary between real science and fake science becomes even more blurred because some people who can legitimately claim to have a science degree, practice pseudo-science. Some of the examples above have been deliberately chosen to demonstrate this point. This is not only very confusing for laypeople, including the press, but it is distressing for scientists who sense that their profession is being compromised.

While it is perhaps understandable that pedlars of snake-oils overstate the claims they make for their products, how is it that people with science backgrounds can indulge in pseudo-science? Coker (2001) suggests that this arises when scientists plunge into disciplines outside their area of competence, and noted that, science is


not a badge (a noun), but an activity (a verb). A scientist can be described as a person who has learned to understand and apply the scientific method – what logical conclusions can be made after considering all the evidence. In this sense, science is a tool, and what differentiates a scientist from a non-scientist is whether the tool of science is being applied in a particular case? Thus, the test that distinguishes a scientist from a pseudo-scientist is not the qualification held by the person, but whether the statements, claims and conclusions made by that person are based on an objective and logical analysis of all the available evidence. The statements recorded above by Drs Anderson and Jones fail this test, despite their qualifications.

Modern science policiesThe case for science has been eroded further by modern science policies and management – science world-wide has been politicised and commercialised. As explained elsewhere (Edmeades 2004, 2009, 2011) these changes shift the focus and purpose of science and technology transfer from its normative3 role to one of finding research dollars and/or serving a political agenda. There is evidence of this in New Zealand as agricultural science ‘cuddles up’ to the ‘organic dollar’ and in the process imbues pseudo-science with a credibility it does not deserve. Some scientists secure and confident in their funding, or because of their professional integrity, resist this urge, but others cannot as two recent examples demonstrate.

The National Institute of Water and Atmosphere (NIWA) is a government owned research organisation. Its website records the average New Zealand temperature for the past one hundred years as shown in Figure 5. This suggests that the average New Zealand temperature has increased since about 1900. The New Zealand Climate Science Coalition has quite legitimately obtained the raw data (Figure 6). It shows no warming.

These data are derived from seven long-term climate stations and there are legitimate reasons

for making adjustments to the record to accommodate changes around, or shifts in, their location. However, after exhaustive enquiries through layers of political obfuscation from the Government and NIWA, Brill (2010a) found that the evidential basis for these changes does not exist. In response to this challenge and to support the earlier Seven Station Series, NIWA published a further graph this time based on an Eleven Station Series. Brill (2010b) exposed this also as a contrivance, achieved by the selection of particular weather records.

Importantly, the issue here is not climate change. It is about the conduct of science. The checks and balances which are essential for the science process to operate, require that science, and in particular publicly funded science, must be open to scrutiny. While it is essential that science is used to inform Government policies, the process of science must never be captured by politics. Is this a local example of sloppy science or is it, what was alluded to earlier – Post-Normal Science – science in the service of a good story? I note that this is a world-wide problem (D’Aleo and Watts 2010).

Universities, once regarded as the bastions of independent free-thought and debate in society, have also been engulfed by the clouds of commercialisation and politicisation as the following example demonstrates.

Ravensdown Fertiliser Cooperative Ltd is marketing a product – a denitrification inhibitor – called EcoN. Based on research from Lincoln University (the patent is owned jointly by the two parties) it is claimed that it can increase pasture production by up to 20% (Cameron et al. 2009). This is an important feature of the marketing message to farmers. I reviewed all the available field trial results in New Zealand (n = 28 trial years) and concluded (Edmeades 2008) that the average pasture response was 2% ± 1%, exactly as predicted based on its nitrogen (N) content (DCD is an N compound).

The problem in this case was not the quality of the research, but the extrapolation of the Lincoln results to the ‘on-farm’ situation. All the research conducted at Lincoln University measured the effects of EcoN in the presence of 3 Normative = pertaining to a norm, establishing a standard.


Figure 5. Adjusted average NZ temperatures from 1860 to 2000 as reported by NIWA. (http:/www.niwa.co.nz/our-science/climate/news/all/nz-temp-record)

Figure 6. Actual average NZ temperatures from 1860 to 2000 from NIWA data. (http://www.climateconversation.wordshine.co.nz/docs/awfw/are-we-feeling-warmer-yet.htm


large N inputs (200 kg urea N/ha and 1000 kg urine N/ha), which of course do not occur in the farm situation. As the researchers themselves say they have been investigating the ‘worst case scenario’. It was in my view, inappropriate to use the Lincoln University results to promote the product to farmers. Is this a case where the commercial imperative distorting the science message?

If the commercialisation of science is here to stay what should be done in such cases to protect the public interest? I think the only solution is that scientists, when writing and commenting about products and services, are made to declare all their private interests, so that the public can make its own assessment as to what weight, if any, should be placed in any opinion and conclusions which are offered.

The organic movement is psuedo-scienceGreen politics is now a given world-wide. In New Zealand, we have a Green Party whose goal is to make New Zealand organic by 2020. Organic farming is becoming legitimate and is attracting research dollars. But the whole organic farming movement is pseudo-science, as I will now discuss.

Prior to the mid 1800s people wondered what the ‘life force4’ was in soils that made plants grow. It was, at that time, reasonable to infer that it may have something to do with the organic matter, because it was known by experience that the application of organic manures and composts did improve plant growth on some soils. The German scientist von Liebig was the first to begin to unravel this mystical knot. He showed that the ‘active ingredients’ (leaving aside water, atmosphere and sunlight for the moment) in soils were nutrients. Limited by the knowledge and technology at the time, he identified just three; nitrogen, phosphorus and potassium. We now know that 16 nutrients are essential for healthy plant growth. Furthermore,

we know conclusively that organic matter per se is not required – this fact is readily demonstrated by growing plant in hydroponics. Thus, the supposed mystical power of organic has evaporated in the light of the evidence.

Despite this evidence the myth of organic matter not only remains, but has become more strident in this post-modern – if I believe it then it is true – era. Indeed, some argue that the only path forward for the world is to adopt ‘organic’ farming practices, which they claim would result in healthier soils, animals and people plus less environmental damage. These claims are false. Goulding et al. (2009) provide evidence from many trials showing that the yields achievable from organic farming are on average about 68% of those that can be achieved by conventional practices. Additionally, there is no evidence that organic foods offer nutritional advantages, relative to conventional food (Woese et al. 1997; Bourn and Prescott 2002; Dangour et al. 2009; Goulding et al. 2009), or that organic fertilisers are better than chemical fertiliser (Edmeades 2003). To complete the picture, Kirkman (2005) has summarised the evidence showing that organic practices do not confer advantages in terms of environmental outcome.

The fact that the organic farming movement is apparently thriving today is itself a measure of the dangerous leniency offered by post-modern thinking. Those people who espouse its cause demonstrate Post-Normal Science in operation – evidence be damned, we must save the planet!

Does it matter?The question arises: does it matter? Is there a legitimate argument to take to science managers, scientists, politicians and society to say pseudo-science is dangerous and should not be tolerated? I think there is.

Liquid fertilisers derived from natural products have been and are marketed to farmers world-wide. Many claims are made for these products based on pseudo-science. I recently reviewed (Edmeades 2002) all the international literature and reported 810 trial-years of data on 28 such products across a wide range of crops. The only possible conclusion was that these products are

4 Soil organic matter of course has many beneficial effects on soil properties including the storage of water and nutrients and the enhancement of soil structure, but it is not essential for plant growth.


ineffective when used as recommended – in fact they were no better or worse than water! Most of this research was conducted by publicly funded government agencies – was it good use of the taxpayers money?

Assuming that field research costs about $NZ 20,000 per trial-year, this represents about $16m in research time and effort. To this must be added the costs incurred by unsuspecting farmers who purchased these products, plus the loss in crop production resulting from their use. If it could be calculated it would represent many millions of dollars. And it was all wasted because it was, and is, entirely predictable based on known science that these products could not work based on the concentrations of what they contained (nutrients, organic matter and plant growth stimulants), and the recommended rates of application. All of this wasted effort and lost production because science was not asserted and pseudo-science prevailed!

Iowa State University maintains a ‘Compendium of research reports on the use of non-traditional materials for crop production’ (Iowa State University 2011). It lists the results for many trials and products. Many of these products are dubious and are marketed on the basis of pseudo-science. Once again the cost in terms of wasted science resources and loss in agricultural productivity must be enormous.

A more local example was reported by Virgona and Daniel (2011). Despite that fact that there is abundant evidence showing that increasing soil P levels in pastoral agriculture can increase productivity and profitability, this technology is not being applied by farmers. While there are likely to be a number of reasons, is it possible that these farmers have not taken up this technology because they have heard the pseudo-science – chemical fertilisers are dangerous, we are ruining our soils? Even if they did not necessarily agree, what effect does such pseudo-science have on their confidence?

Similarly, farmers on both sides of the Tasman are being told by pseudo-scientists that the ‘old’ method of soil testing and fertiliser advice, which is based on scientific evidence, is out-of-date and that a theory, suppressed for years

by the establishment, has been rediscovered – Professor Albrecht’s Base Cation Ratio Theory is now in vogue. Once again this is pseudo-science in action for it is known that the Ratio Theory is, not only technically flawed, but results in grossly incorrect fertiliser advice (Kopittke and Menzies 2007; Fertiliser Review 2011) and hence inefficient agricultural production.

Consider further, if the pseudo-science of ‘organic farming’ was accepted by the majority then it is predictable based on current evidence that the world food production would decline to about 68% of current levels. The options then become stark. Either 32% of the world’s current population would have to starve or the area under cultivation would need to increase substantially, with its concomitant effects on soil erosion from the most vulnerable soils and loss in biodiversity.

The ongoing application of pseudo-science in agriculture is very dangerous – it is wasteful of science resources, results in misleading advice to farmers, undermines farmer’s confidence and cost millions of dollars in lost productivity. If agricultural science is going to meet the challenge of feeding 9 billion people by 2050 and at the same time ensure clean water, clean air and healthy soils and food then the only path forward is for evidence-based progress.

Solutions?Carl Sagan, one of the great astronomers and thinkers of the twentieth century, summed it up succinctly, with what I hope will be immortal words:

‘The only antidote to pseudo science is science itself.’ Carl Sagan

To give effect to Sagan’s imperative, science must be asserted and it must regain its proper moral high ground in society. This is not arrogance for it is not claiming too much. To achieve this there must be changes to science policy and to how science is managed. Science, at least government (publicly) funded science, must be returned to its normative function. Science works best for society if scientists are free to speak openly on matters of public importance, without the fear of either losing their jobs or their funding or


both – the principle of academic freedom must prevail. For it is only when these changes are made that scientists and their managers will once again have the courage and the confidence to speak for science.

‘Those who are fortunate enough to have chosen science as a career have an obligation to inform the public about voodoo science’. Robert Park

References Bourn D, Prescott J (2002) A comparison of the nutritional

value, sensory qualities, and food safety of organically and conventionally produced foods. Critical Review in Food Science and Nutrition 42 (1), 1–34.

Brill B (2010a) Crisis in New Zealand climatology. http::/www.quadrant.org.au/blogs/doomed-planet/2010/05/crisis-in-new-zealand-climatology

Bril l B (2010b). NZ Climate crisis gets worse. http::/www.quadrant.org.au/blogs/doomed-planet/2010/05/nz-climate-crisis-gets-worse.

Cameron KC, Di H, Moir J (2009) The effectiveness of nitrification inhibitor technology to improve the sustainability of agriculture. Primary Industry Management 13: No 4, December 2009.

Coker R (2001) Distinguishing Science and Pseudoscience. http://www.quackwatch.comm/01QuackeryRelatedTopics/pseudo.html

D’Aleo J, Watts A (2010) Surface Temperature Records: Policy Driven Deception? (Science and Public Policy Institute)

Dangour AD, Dohia SK, Hayter A, Allen E, Lock K, Uauy R (2009) Nutritional quality of organic food: a systematic review. American Journal of Clinical Nutrition 90(3), 680–685.

Edmeades DC (2002) The effects of liquid fertiliser derived from natural products on crop, pasture and animal production: a review. Australian Journal of Agricultural Research 53, 965–976.

Edmeades DC (2003) The long-term effects of manures and fertiliser on soil productivity and quality: a review. Nutrient Cycling in Agroecosystems 66, 165–180

Edmeades DC (2004) Is the commercial model appropriate for science? New Zealand Science Review 61(3–4).

Edmeades DC (2009) Science Under Threat: Why and what can be done? Agricultural Science 1/9.

Edmeades DC (2008) The effects of EcoN and DCD on pasture production and nitrate leaching in grazed pastures in New Zealand: A Review. (agKnowledge Ltd.)

Edmeades DC (2011) Technology Transfer can not be Left to Chance. New Zealand Institute of Agriculture and Horticultural Science Inc. AgScience. Issue 38, February 2011: 18–20.

Edmeades GO, Fischer RA, Byerlee D (2010) Can we feed the world in 2050. Proceedings of the New Zealand Grassland Association 72, xxxv–xlii.

Fertiliser Review (2011) Base Saturation Ratios – why they are nonsense. Autumn 2011. http://www.agknowledge.co.nz/agknowledge_Publications.cfm

Geering L (2002) Christianity Without God. Wellington: (Bridget Williams Books 2002 USA: Santa Rosa, Calif: Polebridge press) ISBN 1–877242–24–1.

Goulding KWT, Trewavas AJ, Giller KE (2009) Can Organic Farming Feed the World? International Fertiliser Society Conference. Cambridge 11th December 2009.

Havlin JL, Beaton JD, Tisdale SL, Nelson WL (1999) Soil Fertility and Fertilizers: An Introduction to Nutrient Management. (Prentice Hall, New Jersey)

Iowa State University (2011) Iowa State University, Agronomy Extension www.extension.agronomy.iastate.edu/compendium/index.aspx

Kirkman H, Ryan MH (2005) Nutrient Exclusivity in Organic Farming – Does It Offer Advantages. Better Crops 89, No 1.

Kopittke PM, Menzies NW (2007) A review of the Use of Basic Cation Saturation Ration and the “Ideal” Soil. Soil Science Society of America 71(2), 259–265.

Roche J, Edmeades DC (2005) Fact of Fiction: How do I know who is telling the truth. SIDE Conference, Invercargill, NZ.

Virgona JM, Daniel G (2011) Evidence base agriculture – Can we get there? http://www.grdc.com.au/director/events/researchupdates?item_id=B6FF7BE4B16B2262F62E8DD8A2721FE7&pageNumber=1

Woese K, Lange K, Boess C, Bogl KW (1997) A comparison of organically and conventionally grown food – results of a review of the relevant literature. Journal of Science Food and Agriculture 74, 281–293.


http://www.quackwatch.comm/01QuackeryRelatedTopics/pseudo.html

http://www.quackwatch.comm/01QuackeryRelatedTopics/pseudo.html

http://www.agknowledge.co.nz/agknowledge_Publications.cfm

http://www.agknowledge.co.nz/agknowledge_Publications.cfm

http://www.extension.agronomy.iastate.edu/compendium/index.aspx

http://www.extension.agronomy.iastate.edu/compendium/index.aspx

http://www.grdc.com.au/director/events/researchupdates?item_id=B6FF7BE4B16B2262F62E8DD8A2721FE7&pageNumber=1



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Soil chemistry – facts and fiction and their influence on the fertiliser decision making process

N. Menzies,A D. Harbison B and P. DartA

AThe University of Queensland. BD R Agriculture Pty Ltd.

Take home message: Trust nobody! – test it yourself, but test it properly.

Preamble – the legal problem presented by speaking about productsOne of the first constraints to a scientist in presenting a paper like this, is the risk that the statements made, may be viewed by those with a commercial interest in selling products to farmers, as so damaging (or so wrong) that they need to respond by taking legal action against the scientist. Even the threat of legal action may be so daunting that the scientist or the employer may prefer to remain silent. One of the most celebrated examples of this is the Maxicrop case, in which the Bell-Booth Group sued the New Zealand Ministry of Agriculture and Fisheries (MAF) and Dr Doug Edmeades personally for damages (initially $5.5 million, later amended to $11.5 million). This story is wonderfully presented in Edmeades’ book ‘Science Friction. The Maxicrop case and the aftermath’ (Edmeades DC 2000. ISBN 0 473 06886 9, Published by Fertiliser Information Services Ltd., P.O. Box 9147, Hamilton, New Zealand), and the underlying science published in the Australian Journal of Agricultural Research – Edmeades DC 2002. The effects of liquid fertilisers derived from natural products on crop, pasture, and animal production: a review. Australian Journal of Agricultural Research 53, 965–976. A snap shot of the case is reported here, as it provides some insight into how some ‘responses’ can be obtained.

Maxicrop is a concentrated seaweed extract, which was promoted as a fertiliser, providing nutrients and plant hormones. The recommended application rates, highly diluted, meant that it was considerably cheaper than conventional fertilisers. As with farmers everywhere, New Zealand farmers in the mid-1980s were subject to economic pressures, and with fertilisers as a major cost a cheaper alternative was welcomed.

After extensively reviewing the world literature on non-traditional fertilisers, analysing Maxicrop, and undertaking field trials with it, Dr. Edmeades came to the conclusion that, used as directed, the product could not possibly provide the claimed benefits. In April 1985, Dr. Edmeades appeared on the TVNZ program ‘Fair Go’ with Mark Bell-Booth and David Bellamy in which he presented his case against Maxicrop. It was this program which provided the basis for the subsequent legal action. One aspect of the company’s case was the claim that Maxicrop did work in some situations (increasing crop yield), and while they could not accurately predict which conditions it would work under, there was nevertheless evidence that the product did work. The real difficulty for Doug Edmeades and MAF was to explain to people trained in law, rather than natural sciences, that natural variability (in statistical terms – error) would result in Maxicrop occasionally producing a yield greater than the control. One of the key pieces of information that helped the lawyers grasp this idea was a set of data showing the response of crops to an application of water (Figure 1, from Edmeades 2002).

Figure 1. Frequency distribution of crop responses to water (225 L/Ha) expressed as the increase or decrease (%) relative to the control (data from Wadsworth 1987).


From Figure 1, you can see that occasionally an application of water reduced crop growth (by almost 20% in a very small number of instances). Conversely, water also increased yield in some instances. The key aspect of this set of data is that the data points are centred around zero (the mean is actually –0.6% and confidence interval 2.3%). In fact, the application of water had no effect on yield, the range of results obtained is consistent with variability normally associated with this type of experiment.

Using this basic understanding of variability, it was apparent to the court that Maxicrop did not work, and that the occasions when it appeared to increase yield were simply random variation (experimental error). Frequency distributions for Maxicrop and several other similar liquid fertilisers are presented below overlaid with the response to water in each of the trials (Figure 2 from Edmeades 2002). Overall a great demonstration that materials of this type

(low nutrient concentration, and compounds intended to act as plant growth stimulants) are not effective fertilisers.

Ultimately, the judgement mostly went against the plaintiffs except in one regard. In relation to the claim of negligence the judge, Justice Ellis, stated, ‘MAF is in the most general way under a duty to act fairly to all citizens. This involves balancing competing interests. The present case is a good example. MAF must in my view balance its primary obligations and duties to the pastoral and agricultural industries and to the vendors of products consumed by such. In general terms, I consider that where an agency such as MAF intends to condemn a product it must give the seller an adequate and fair opportunity to consider such publicity beforehand and make its responses before the damage is done.’ Consequently his Honour found that MAF had breached this duty of care and had acted negligently, awarding the Bell-Booth Group $25,000.

Figure 2. Frequency distributions for Maxicrop (seaweed), Siapton (animal offal extract), SM3 (seaweed), and Stimufol (vegetable).


The company was not satisfied with this tiny victory and appealed to the Court of Appeal, which provided no encouragement and overturned the negligence verdict, observing inter alia that, ‘Some of the arguments for the company go close to asserting that a manufacturer has a right to sell worthless goods as long as he honestly believes that they are some use. We would see that as putting it over-simply. Those who reasonably believe that the goods are worthless must have an equal right to say so.’ Despite the clear defeat of the plaintiff, who had initiated the case, the view was widely expressed that the powers of government had been used to crush a small struggling entrepreneur.

Despite the eventual court decision, the case cost Doug Edmeades at least 18 months of his professional career; it was undoubtedly also a most harrowing experience. Further, as explained by Dr Edmeades in ‘Science Friction’ MAF were subsequently very hesitant to allow their scientists to publish results that did not support a commercial product. ‘How does this help farmers?’ we might well ask. We have no desire to follow in Doug’s footsteps, so we are setting some rigorous rules in what we intend to say and how we can justify these statements. Throughout this paper, we will stick to reporting to you the ‘science’ (Doug Edmeades also did this, but it still was not enough to keep him safe). We will not refer to specific products. However, we do want to provide you with something useful, so we will attempt to provide you with a way to think about products which are intended to improve plant growth through their influence on soil biology. We also make some suggestions of how to go about testing these products yourself.

The nature of science and of faith – we will stick to scienceThe basic nature of science is to form a hypothesis which explains an observation; this hypothesis is then tested. If through repeated testing the hypothesis is shown to account for the observations, then it is regarded as a theory. In scientific terms, ‘theory’ does not mean ‘guess’ or ‘hunch’ as it does in everyday usage. Scientific theories are explanations of natural phenomena built up logically from testable observations and

hypotheses. Scientists generally use the term ‘fact’ to mean something that has been tested or observed so many times that there is no longer a compelling reason to keep testing or looking for examples.

In contrast, faith is something one ‘believes in’. It serves a major evolutionary purpose and has been an essential part of human nature since time immemorial. When shared by members of a group, faith strongly supports that group’s internal cohesion. It strengthens the group’s capacity to cope with the challenges of a hostile environment. It adds to the group’s capacity to compete successfully with other groups animated by different faiths. But there is a dark side to the ‘in group’ – whether religious or not – by definition, there is an ‘out-group’. A basis for hostility – often extreme – if we are not careful. All religion is based on faith, but not all faith needs to be religious, at least in the sense of requiring adherence to a recognised religious persuasion (from Carl Croon – Progressive Humanism).

Clarity at the extremesLet’s briefly look at examples that are readily accepted as sitting near the opposing ends of this Science – Faith spectrum.

One clear endpoint – Science; illustrated by symbiotic N2-fixationThe rhizobium–legume symbiosis is a good example of science. In this unique association between organisms, the plant provides a source of energy and an ecological niche for the bacterium, which in return synthesises ammonia for the host plant. Despite millions of years of evolution, higher plants have not developed a N2-fixation system. At the global scale, the rhizobium-legume symbiosis provides a quantity of fixed nitrogen (N) comparable to that produced by the entire chemical fertiliser industry, and thus plays a major ecological and economic role (Table 1). The symbiosis has been the subject of a great deal of scientific investigation, and we now understand it at a genetic, biochemical and ecological level. Furthermore, we understand it well enough that the system can be, and is,


effectively manipulated in farmers’ fields all over the world.

Table 1. Major annual terrestrial N inputs. Fixation by legume crops is subdivided to show the importance of soybean. (Simil 1997; Herridge et al. 2008).

Source Nitrogen fixed (Tg)

Natural biological N fixation 90–140

Lightning <10

Symbiotic N fixation by crop legumes

22

Soybean 16

Peanut 2

chickpea 0.6

Pasture legumes 12–25

Fertiliser 160

This is a true symbiosis – each organism gains an advantage – the rhizobium with energy and the legume with fixed N.

The other clear endpoint – faith; illustrated by homeopathyAt the other extreme, homeopathy is viewed by scientists as representing an example of faith. A central thesis of homeopathy is that an ill person can be treated using a substance that can produce, in a healthy person, symptoms similar to those of the illness. Practitioners select treatments based on consultation that explores the physical and psychological state of the patient (not a bad idea!), both of which are considered important to selecting the remedy. According to Hahnemann, one of the key figures in the development of the approach, serial dilution, with shaking between each dilution, removes the toxic effects of the substance, while the essential qualities are retained by the diluent (water, sugar, or alcohol). Claims to the efficacy of homeopathic treatment beyond the placebo effect are unsupported by the collective weight of scientific and clinical evidence. Common homeopathic preparations are often indistinguishable from the pure diluent because the purported medicinal compound is diluted beyond the point where there is any likelihood that molecules from the original solution are present in the final product; the claim that these treatments still have any pharmacological effect is thus scientifically

implausible and violates fundamental principles of science. Critics also object that the number of high-quality studies that support homeopathy is small, the conclusions are not definitive, and duplication of the results, a key test of scientific validity, has proven problematic at best. The lack of convincing scientific evidence supporting its efficacy and its use of remedies without active ingredients have caused homeopathy to be regarded as pseudoscience or quackery (from the reference most loved by university lecturers – Wikipedia). Also, in some instances, a belief in the benefit of a treatment is considered a prerequisite for its efficacy – this precludes scientific testing.

The dilutions advocated in homeopathy are extreme. A 1060 dilution was advocated by Hahnemann for most purposes. Some trivial calculations put this dilution in context – if you used a medicine diluted to 1060, you would need to give two billion doses per second, to six billion people (the world’s population), for 4 billion years, to deliver a single molecule of the original material to any patient. One third of a drop of some original substance diluted into all the water on earth would produce a remedy with a concentration of about 1026 (once again I am trusting Wikipedia for this value).

The difficult middle groundThe extremes are easy – we can readily accept or reject ideas (or products) for which there is clear evidence and understanding on which to base our decision. Our decision-making task is much more difficult when there has been only limited investigation, and hence there is little information, or when the results of investigations appear to be inconsistent.

We will develop two examples here. The first, ‘P-solubilisation by free living organisms’ provides an example where there is a clear underpinning mechanism. The question we will attempt to address is: Can this process be manipulated and enhanced? From the perspective of a farmer, the question would be: Are products which claim to do this, worth the investment? The second example of the ‘Ideal Cation Ratio’ demonstrates poor science – selecting only the results which


suit your viewpoint, even if the research was poorly conducted.

It is very difficult to compare growth of plants with and without microbes, as plants growing with microbes, is the natural condition. Plant roots are surrounded by a mucilaginous layer, the ‘mucigel’ mainly exuded from the root tip. The space immediately surrounding the root, where microbes grow in greater numbers than in the bulk soil, is known as the rhizosphere which usually extends about 1–2 mm from the root. The plant exudate contains a wide range of amino acids, sugars, organic acids and vitamins. Some bacteria are selectively stimulated to multiply by this substrate. The amount of carbon in the photosynthate exuded into the rhizosphere can be as much as 25–30% of the total amount fixed by photosynthesis.

So much of the plants energy is invested in rhizosphere functions. One of these is to develop a population of microbes, both bacteria and fungi, which protects the plant from infection by pathogens and plays a role in plant nutrition and plant growth stimulation through production of plant hormones. There is a homeostatic process operating in the rhizosphere so that the numbers of a particular organism reach an equilibrium level. The microbes respond to plant signals which affect their gene expression, and also through a process known as quorum sensing, where microbes limit their own population development once a certain level has been reached. Most of the organisms living in the rhizosphere and the bulk soil cannot at present be grown in culture medium. The genetic diversity of the soil microbial population can be affected by the farming system, soil type and plants grown. So we have a very complex system which, as we shall show with our P uptake example, has feedback interactions also. There is a lot we do not know about the plant microbe interactions in the soil. So the way to see if we can manipulate the system to be economically beneficial for sustainable agricultural production is to undertake very well designed empirical experiments properly replicated over time and environment, soil type and farming system.

In the bulk soil and rhizosphere, microbes are responsible for mineralising (breaking down) organic matter, thereby releasing nutrients for plant uptake and growth. The benefits accruing for plant growth from richly organic soils is directly the result of microbial activity. However, all of these benefits are from microbes existing naturally at sufficient populations in soils to undertake this process of mineralisation, growth stimulation, pathogen control, etc. For processes like mineralisation, there is invariably no need to add any more micro-organisms to the soil. In the following sections we explore the question, of whether adding additional organisms is ever effective. We develop this question in our example of plant microbe interactions – it’s for you to judge if we have managed to answer it.

Ambiguity – phosphorus solubilising organismsAfter N, phosphorus (P) is the most commonly limiting nutrient in soils around the world. Soils typically have a reasonably large store of P, many soils contain a total P store sufficient for 100 years of farming, but the problem is that most of this P is not in a form which is available for plant uptake. Plants take up P directly from soil solution as orthophosphate (HPO4

2- and H2PO4

-). As the soil solution P is depleted, other pools of P that are held on the solid phase of the soil will be released into solution. For example, P that is adsorbed to soil minerals desorbs, thus buffering the P in the soil solution. Another pool of P in the soil is organic-P which, like N in the organic matter, needs to be mineralised in order to be available for plant uptake. Typically, 20 to 70% of the total soil P is in this organic pool in mineral soils (values for organic soils and peats are much higher, of course). Many plants, including wheat, can achieve the release of part of this organic-P through the release and action of the enzymes called phosphatases. Production of phosphatase is enhanced by low P conditions. The phosphatase enzymes achieve release of orthophosphate from the soil compounds however, they account for only a minor part of the soil organic-P and generally are not present in soil in sufficient quantities to supply an actively growing plant’s needs. Most


of the remaining organic-P cannot be readily accessed by the roots of most plants, but release by the plant of root exudates acts as an energy source for organisms which are able to produce enzymes capable of releasing this organic-P. The concentration of organic-P near the roots of wheat can decrease dramatically (by 86% in a study by Tarafdar and Jungk 1987). So organisms which mobilise organic-P are clearly important. In this paper, we will concentrate on organisms which are capable of mobilising P from inorganic forms.

Plant P solubilisation. Some plants can themselves solubilise inorganic-P from the soil solid phase in order to make it available for uptake. A few plants that are adapted to low P soils, for example lupin (Lupinus albus) excrete acidifying compounds (e.g. citric and malic acids) enabling solubilisation and uptake of P into the plant. Most plants (including wheat and maize) do not appear to do this. Acidification can solubilise P in alkaline soils, but this strategy is not effective in acid soils. Members of the plant family Proteaceae are particularly effective at producing and excreting organic acids into the root zone. Plants of this family (and a number of other families) are able to form cluster roots. This structure permits the effect of organic acid release to be concentrated in a limited volume of soil to maximise its effectiveness. We can regard these plants as mining P, by forcing its release from the solid phase. In contrast, the mycorrhizal associations of many crop plants could be considered as scavengers, picking up whatever free P (P in the soil solution) they can find. Mycorrhizal associations are more effective in soils where the soil solution P concentration is somewhat higher than that in soils where Proteaceae are abundant (Lambers et al. 2008).

It’s worth considering the energy (carbon) cost to the plant of obtaining P by different strategies. In soils with a reasonable P status, the roots and root hairs are sufficient to obtain sufficient P. As P becomes more limiting, the plant will invest more of the carbon it fixes through photosynthesis, and this can be seen in an increased root to shoot ratio (more roots and fewer shoots). In still lower P environments, mycorrhizal associations are beneficial to the

plant – it costs less energy to support a network of fungal hyphae than it does to build a system of roots and root hairs. For mycorrhizal plants, 4 to 20% of carbon fixed in photosynthesis is used by the mycorrhiza. It is interesting to note that the formation of the plant-mycorrhizal symbiosis is affected by P supply; plants do not form an association in high P soils, as feeding the fungus would represent an unnecessary expenditure in this situation. Finally, the production of cluster roots and release of organic acids is extremely energy expensive; the plants strategy is to acquire P at any cost (Lynch and Ho 2005). It is no surprise that plants which do this are slow growing. Energy cost is clearly critical when we are considering a crop or pasture situation, as any additional investment in obtaining nutrients can reduce yield.

Free living solubilisers. Micro-organisms capable of solubilising P are ubiquitous in soils, with 1 to 50% of the total bacterial population, and 0.1 to 0.5% of the total fungal population capable of solubilising P. The P-solubilising bacteria typically outnumber P-solubilising fungi by 2- to 150-fold, though fungal isolates exhibit greater solubilising ability (Gyansehwar et al. 2002). The simplest mechanism of P solubilisation by the microbes is through acidification of the organism’s growth environment. This acidification can simply be a reflection of the nature of the N supply; organisms supplied with N in the growth medium primarily in the ammonium (NH4

+) form excrete protons in order to maintain electron neutrality (they have the problem of taking up too many cations – Ca2+, Mg2+, K+, NH4

+, and too few anions – SO4

2-, PO43-, NO3

-, and must balance this by pumping out H+). In poorly designed laboratory experiments, if N is supplied as ammonium, this results in many organisms being able to solubilise calcium phosphate by this mechanism. This is unlikely to happen in soil because nitrate and not ammonium is the normal source of N for the microbes. The other main P solubilisation strategy is the production and release of organic acids, similar to the process described above for plants.

Before leaving the rhizosphere its worth considering how long the organic acids will


continue to work for, and how large a zone of influence there may be around a P solubilising organism. Organic acids represent an energy source for soil organisms (food for bugs). Studies on the breakdown of organic acids such as citrate and malate added to soil at realistic concentrations similar to rhizosphere concentrations show that the acids are rapidly degraded in bulk (non-rhizosphere) soil – the half life is about 2 to 3 hours (i.e. microorganisms will degrade half of the organic acid added at these rhizosphere level concentrations to simpler carbon compounds in 2 to 3 hours). In the rhizosphere itself, where there is a much higher population of organisms, degradation will be 2 to 3 times faster (Jones 1998). As for the zone of influence – because organic acids are strongly bound by the soil, they do not move far; the predicted zone of influence for a root is 0.2 to 1.0 mm (Jones 1998). The influence of an individual organism/colony would be a small fraction of this. If we also consider that P is relatively immobile in the soil – clearly, the organism would have to be in the rhizosphere to have any impact on plant growth. Inoculation of the seed, and hence the rhizosphere may work, but treating the bulk soil is very unlikely to be effective.

Field effectiveness of P solubilising organisms. The involvement of micro-organisms in solubilisation of P has been known for more than 100 years, and there is a substantial literature dealing with this issue. However, most research has been at the laboratory culture (petri dish), or glasshouse pot trial scale; the number of field trials is quite small. Unfortunately, there is no simple message from the field trials; some trials showed growth enhancement and/or increased P uptake, but there is large variation in the effectiveness of inoculation with P solubilising organisms (Kucey et al. 1989; Gyaneshwar et al. 2002). Tandon (1987) undertook a review of this research, and while this report is now 20 years old, the conclusions he reached at that time are still applicable today. Tandon reported that inoculation resulted in 10 to 15% yield increases in 10 out of the 37 experiments he considered; in the remaining trials (70% of cases) there was no increase. Furthermore, he (and subsequent

reviewers) considered that even in the trials that showed a yield increase, there was reason to question the validity of the findings. Two of his most important concerns were that:• In many trials, the inoculation with

P-solubilising organisms was not compared to addition of soluble P fertiliser, so there is no direct evidence that plants would respond to increased P availability in these soils. (This is still a valid criticism of recent publications – indeed, some papers provide data to show that the plants do not respond to P fertiliser; i.e. that the soil is not P deficient.)

• Themechanismforplantgrowthpromotingactivity of P-solubilising organisms, other than P solubilisation, has not been demonstrated, but has often been claimed. For example, claims that the organisms may produce plant hormones which increase growth. Certainly some P-solubilising organisms do produce plant hormones (e.g. indole-acetic acid), but the impact of this on plant growth has not been established.

We undertook a rapid review of papers published since Tandon’s 1987 review. On the basis of the number of published papers, research on P-solubilising organisms is concentrated in a limited number of counties (Table 2), with India dominating. Of the field studies published, 10 papers show a yield or biomass increase as a result of inoculation, and seven show no effect. Of the papers showing a beneficial effect of inoculation with P-solubilising organisms, the benefit ranged from a modest increase (e.g. 10%), to more than two-fold increase in one instance. We considered that the results of a further 18 papers could not be reliably interpreted. These papers had one (or several) of three types of limitations.• TheeffectofP-solubilisingorganismscould

not be separated from the effect of other beneficial organisms. In several studies, using legume test species, a mixed inoculum consisting of rhizobium, P-solubilising organisms, and other organisms considered to be beneficial was applied. A beneficial effect of N supply through nodulation could be expected.


• In many studies no effort was made toestablish that the soil was P responsive at all, or within the range of P application used as treatments. In India, it is common to compare a ‘recommended’ rate of P fertiliser with a fraction of this rate (e.g. 75%) plus P-solubilising organism inoculation. If these treatments achieve the same yield, the researchers interpret this as a demonstration that P-solubilisation has replaced the remaining (25%) fertiliser. This would only be valid if increasing the fertiliser rate did increase yield, and this was not demonstrated. It may be that 75% of the fertiliser was sufficient to achieve maximum yield, and that the inoculation did nothing.

• A limited number of experiments usedtreatments of fertiliser, and the same rate of fertiliser plus P-solubilising organism inoculation. If these treatments achieved the same yield, then the researchers interpreted this as a demonstration that P-solubilisation did not occur. Once again, this would only be true if the addition of more P increased plant yield, and this was not demonstrated. It is possible that solubilisation did occur, but the plant was already adequately supplied with P and hence did not grow any better or was limited in its growth by the lack of other nutrients.

Table 2. Origin and nature of research on P-solubilising organisms.

Country where research was undertaken

Total number of papers

Number of field studies

India 34 16

China 11 4

Brazil 9 1

Turkey 9 5

Canada 8 2

Czechoslovakia 7 2

Others 19 5

Organisms which are capable of P solubilisation in the laboratory, often fail to achieve this in soil. This can in part be attributed to the more strongly buffered nature of soil systems (relative to laboratory microbial growth media).

Organisms which produce acid can solubilise P in poorly buffered media, because the pH is easily lowered by production of H+. However, it requires a great deal more acid production to solubilise P in a buffered soil, and few organisms can achieve this. This is especially true for vertosols, which may contain high levels of lime (calcium carbonate), and are thus able to maintain a constant pH even when relatively large amounts of H+ are added.

We have had the opportunity to test P-solubilising bacteria as part of an ACIAR project we have been undertaking in Madhya Pradesh, India, with scientists from the Indian Institute of Soil Science (IISS). The inoculum used was a mixture of P-solubilising bacteria selected to be effective across a wide range of soil types and crops. This inoculum was developed by scientists at IISS, and is available commercially to farmers in India. Four replicated experiments were undertaken (two experiments in two districts) for two years (2005−2006). Individual plots were 60 m x 4.5 m. The five treatments applied were inorganic fertiliser at the recommended rate (100%), fertiliser at 75% of the recommended rate (75%), fertiliser at 75% of the recommended rate plus P-solubilising bacteria (75%+PSB), an organic treatment of 8 t/ha of farm yard manure (Org), and this organic treatment plus P-solubilising bacteria (Org+PSB). The recommended P fertiliser rate for the area is 26 kg P/ha, and this

100% 75

%

75%

+PSB Or

g

Org +

PSB

Yield

(t/ha

)

0

2

4

6

8

10

12

14

100% 75

%

75%

+PSB Or

g

Org +

PSB

StrawGrain

2005 2006

Figure 3. Average grain and straw yields for wheat grown using inorganic fertilisation, or organic fertilisation, with (+PSB) or without inoculation of seed with P-solubilising bacteria. Yields are the mean of four experiments. The shading of the histogram indicates straw (black) and grain (grey).


was the rate used in the 100% treatment. Other nutrients likely to be limiting plant growth were identified in earlier glasshouse nutrient omission experiments where growth is compared with a complete nutrient addition and this minus the element under test). These nutrients (in this case N, S, and Zn) were added as a basal application to the 100%, 75% and 75%+PSB treatments. The test crop was wheat, grown in the winter or rabi season and the soil at each site was a vertosol. The crops typically received four irrigations. Across all four experiments in each of the two years, there was no significant grain or straw yield increase (Figure 3), or additional P uptake, as a result of the P-solubilising bacteria.

One final published study, that of Karamanos et al. (2010) is worth mentioning, because it considers the organism Penicillium bilaii. You will find this is the active ingredient in several commercial products currently available in the Australian marketplace. Karamanos and his co-authors considered the results of 47 experiments carried out from 1989 to 1995 to assess the benefit of P. bilaii inoculation of wheat on the Canadian prairie. In 33 of these experiments, there was a response to P fertiliser (i.e. the soil was P deficient). In 14 experiments, there was a response to P. bilaii – in five, the inoculation increased yield, and in nine the inoculation deceased yield. These responses appear to be random events. The inoculation with this commercially available organism did not work. Phosphorus fertiliser did work, and would clearly have been a better investment for the farmers. It is important to note that in 14 trials, there was no response to P fertiliser; the soil simply was not P deficient. This highlights the value of soil testing. The soil test response is shown in Figure 4, which shows clearly the yield response to P availability. It also shows clearly the total lack of response to P. bilaii.

Where does all of this leave us? We need to consider what benefit could be expected from seed inoculation. As soils contain large numbers of organisms capable of solubilising P, inoculation would only be of benefit if the inoculated strain was much more effective than the organisms already present in the soil. On the basis of the published literature, inoculation does appear to

work sometimes (albeit infrequently), but the circumstances in which this will occur reliably have certainly not been established. At this time we are unable to predict when a positive response will be obtained. A series of trials over different years, in a range of soil types would be needed to establish the reproducibility of the response. Rarely is this done with microbial inoculation experiments, and the example we considered (Karamanos et al. 2010), provides a clear demonstration that for the organism tested there was no benefit. When inoculation with P-solubilising organisms does work, most trials have shown a modest increase in P availability and of crop yield (somewhere in the 10% range). When you consider the substantial energy cost of P solubilisation, a modest increase is probably all you should expect.

Poor science – the ideal cation saturation ratioOur early understanding of crop nutritional requirements and their response to soil conditions came through observation; the progressive development of hypotheses about soil-plant relationships which could then be rigorously tested. The concept of ideal cation saturation ratios has this history. During the 1940s and 1950s there were a series of reports proposing ‘ideal’ proportions of exchangeable cations in soil (Bear et al. 1945; Bear and Toth 1948; Graham 1959). The proposed ranges were 65 to 75% Ca2+, about 10% Mg2+, 2.5 to 5% K+, and 10 to 20% H+, or approximate ratios of 7:1

Figure 4. Soil test calibration curve for bicarbonate extractable P with wheat ( + or – P. bilaii). Relative yields are a percentage of the yield obtained with a P application of 13.1 kg/ha.


for Ca/Mg, 15:1 for Ca/K, and 3:1 for Mg/K. Without question, soils with this cation make-up would not present any problems for plant growth with respect to these nutrients. However, our question is, ‘will plants grow better if we adjust the cation ratios of the soil to these values?’ A couple of key points need to be made about this approach:• The method was proposed by scientists

working in areas of the USA where there are very good soils with negligible nutrient element deficiencies. At the time this work was performed, fertiliser applications were not required to overcome deficiency of the cationic nutrient elements to achieve profitable production. That is, adding cationic fertiliser to these soils usually had no impact on production. The method requires measuring the cation exchange capacity of soils that is balanced by calcium, magnesium and potassium. Then fertiliser advice is provided so as to achieve the desired ratio of these elements balancing the surface charge. The method does not involve measuring production responses to the added fertiliser.

• We now understand that most of theexchangeable H+ that we measure in soils is an experimental artefact; it does not really exist. The exchangeable H+ that was measured resulted from an increase in surface charge density (CEC) as a result of using a high ionic strength saturating solution (commonly 1 M) (van Olphen 1977). With the development of more appropriate methods of measuring cation exchange capacity (e.g. Gillman and Sumpter 1986) exchangeable H+ is not found at measurable concentrations except in the most acid soils (pH water<4.5).

During the 1940s, Bear and co-workers conducted a series of studies at the New Jersey Agricultural Experiment Station investigating the growth of alfalfa (Medicago sativa). As part of this research Bear and coworkers proposed the ‘ideal ratio’ of exchangeable cations in the soil. Since the publication of these ratios by Bear, it has been assumed by many that optimum plant growth will only occur when these ‘ideal’ conditions are met. This is despite Bear and co-workers’ acknowledgement that maximum

growth will occur over a wide variety of cation ratios. In their work, the purpose of providing a high Ca saturation (65%) was to allow maximum growth whilst also minimising luxury K uptake. Indeed, Bear and co-workers logic was as follows: (1) good growth occurs across a wide range of Ca:K ratios, (2) a high Ca saturation percentage limits luxury K uptake, and (3) ‘K is a much more expensive element than the Ca which it replaces’ (Bear and Toth 1948). Thus, the application of Ca to reduce K uptake was cheaper than applying K which would be taken up by the plant in luxurious amounts. Although split-K applications was considered as a method for reducing luxury K uptake (Bear and Toth 1948), it appears that this practice was never explored in detail.

At about the same time that Bear was conducting his investigations, Albrecht and co-workers were also conducting a series of experiments at the Missouri Agricultural Experiment Station. Much of their research investigated the growth (and N2-fixation) of legumes, and examined the effect of soil fertility on plant palatability and the nutrition of grazing animals. In many of these studies conducted by Albrecht, clay minerals were extracted from the soil, subjected to electrodialysis, then saturated with various cations such as Ca, K, Mg, and Ba [see Albrecht and McCalla (1938)]. By mixing these clays at different ratios, Albrecht was able to investigate the effect of cation saturation on plant growth.

Albrecht concluded that it is important to maintain a high Ca saturation percentage. Indeed, it was this observation which would eventually form the basis for much of Albrecht’s concept of the ‘balanced soil’. However, it would seem that the design and interpretation of the experiments used to demonstrate the need for a high Ca saturation were often flawed. Based on experiments with soybean (Glycine max), Albrecht (1937) concluded that (1) the nodulation of legumes in acidic soils is limited by low Ca concentrations more than by the acidity itself, and (2) plant growth and nodulation increase as Ca saturation increases. In fact, Albrecht later stated that ‘plants are not sensitive to, or limited by, a particular pH value of the soil’ (Albrecht, 1975) and that ‘nitrogen fixation


is related to acidity, or pH, only as this represents a decreasing supply of Ca as a plant nutrient’ (Albrecht 1939). However, examination of the data of Albrecht (1937) reveals that nodulation is indeed inhibited by soil acidity; nodulation only occurred when the pH was ≥ 5.5, and no nodulation occurred at pH 4.0, 4.5, or 5.0 at any Ca concentration (so Albrecht misinterpreted his own data). According to ‘The Albrecht Papers’ (Albrecht 1975), Albrecht (1939) demonstrated that for a ‘balanced soil’, ‘65% of that clay’s capacity (needs to be) loaded with Ca, 15% with Mg’. However, it is unclear how these ‘balanced’ percentages were derived, as examination reveals that the rate of N2-fixation (measured as the difference in N content between the plant and the seed) increased linearly with Ca-saturation – the greatest fixation actually occurring at the highest rate of Ca-saturation, i.e. 88% (vs. the ‘balanced’ Ca saturation of 65%). Similarly, the work of Albrecht (1937) showed that both plant mass and nodulation rate increased linearly with increasing Ca saturation. Later, and notably after the work of Bear and Graham had been published, Albrecht stated that ‘extensive research projects served up this working code for balanced plant nutrition: H, 10%; Ca, 60–75%; Mg, 10-20%; K, 2–5%; Na, 0.5–5.0%; and other cations, 5%’ (Albrecht 1975). Whilst it is unclear as to the exact origin of Albrecht’s ‘balanced soil’, it appears likely that it relied, at least to some extent, upon the ‘ideal soil’ of Bear and co-workers.

That the ‘ideal’ cation exchange ratio idea received so much attention at the time is surprising, given that, at the same time, other researchers were reporting that it did not work. Hunter and associates in New Jersey (Hunter 1949) could find no ideal Ca/Mg or Ca/K ratios for alfalfa, nor did Foy and Barber (1958) find yield response of maize (Zea mays) to varying K/Mg ratio in Indiana. A comprehensive and elegant demonstration of the failure of the approach is presented by the glasshouse and field studies of McLean and co-workers (Eckert and McLean 1981; McLean et al. 1983), where Ca, Mg and K were varied relative to each other. They concluded that the ratio had essentially no impact on yields except at extremely wide ratios

where a deficiency of one element was caused by excesses of others. They emphasised the need for assuring that sufficient levels of each cation were present, rather than attempting adjustment to a non-existent ideal cation saturation ratio.

One of the reasons that the cation saturation ratio idea has persisted, is that, in very general terms, there is just enough ‘truth’ in it to make it seem reasonable.

A calcium deficiency case studyCalcium deficiency induced through the use of magnesium oxide as a liming material

With the development of a magnesium mining and refining industry in Queensland, the opportunity to use by-product MgO as a liming material became possible, and was considered a practical approach to ameliorating acid, magnesium deficient soils. Dr Kylie Hailes undertook research on this issue for her PhD under the supervision of Dr Bob Aitken and myself. In her work, Kylie investigated amelioration of acidity using MgO, mixtures of MgO and CaSO4 (gypsum), and compared this to lime. She measured short-term root elongation of maize and mungbean as an indication of aluminium toxicity and of calcium deficiency. I have removed the low pH values, where aluminium toxicity will have limited root growth, so that the primary factor influencing root growth is calcium supply. As you can see from the data in Figures 5 and 6, root growth reaches a maximum by 20% calcium saturation of the exchange, or a Ca/Mg ratio of 0.5. Clearly there was no need to reach the 60 to 70% calcium saturation advocated in the ‘cation saturation approach’.

Finally, and as an aside on the cation saturation ratio issue, advocates of the cation saturation ratios approach present an ‘ideal’ situation as being a soil with a pH of 6.0 to 6.5, and a distribution of cations including 12% of the cation occupancy being by H+. To a soil chemist, this really calls into question the credibility of the approach; for the simple reason that it would not be possible for the exchange to have so much exchangeable H+ at this pH. Vietch (1904) recognised at the turn of the century that


negatively charged (higher cation exchange capacity), and it does this by loosing H+ from the surface. By measuring cation exchange with concentrated solutions at high pH, you get a cation exchange measurement that is too large, and you incorrectly measure a lot of H+ as being present.

To conclude this section on plant Ca and Mg nutrition I will restate the take-home message I started with;

The ratio of exchangeable calcium and magnesium in soil will not influence plant growth, except at extreme values seldom encountered in agricultural soils.and add to it to the conclusion from Lipman (1916) when he reviewed the same topic.‘I have known of measures employed in soil management in this state, based on theory of the lime-magnesia ratio as first enunciated by Loew and later exploited by unscientific men, which to the rational-minded experimenter in soils and plants, appeared to be the veriest folly’

Cation ratio effects on physical fertilityThe ‘ideal’ cation balance paradigm also postulates an effect of cation ratios on plant growth through changes in soil structure, in particular, surface-crusting, hardsetting, and decreased hydraulic conductivity (i.e. increased run-off ). The high exchangeable Ca content (65%) of an ‘ideal soil’ is undoubtedly beneficial in maintaining and improving soil structure and aggregate stability (see Amézketa (1999) for a review). However, the concern arises that if the soil Ca content is lower (and the Mg higher) than that recommended by the BCSR, then soil structure may decline. This concern is based on the observation that soil aggregates 100% saturated with Ca are less likely to disperse than those saturated with Mg (Rengasamy 1983). In fact, whilst a ‘balanced soil’ is likely to have good structure, this structure can be maintained across a range of Ca:Mg ratios – the ‘ideal’ ratio is unnecessary. For example, Rengasamy et al. (1986) demonstrated that structure of a red-brown earth (Rhodoxeralf ) (as measured by hydraulic conductivity) was maintained across a variety of Ca:Mg ratios (Figure 7).

Ca : Mg ratio

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Figure 6. The effect of Ca to Mg ratio on the rate of root elongation (a measure of Ca deficiency) for maize and mungbean in acid soils limed with MgO and mixtures of MgO and CaSO4.

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Figure 5. The effect of Ca saturation on the rate of root elongation (a measure of Ca deficiency) for maize and mungbean in acid soils limed with MgO and mixtures of MgO and CaSO4.

acid soils were aluminium saturated, rather than H+ saturated. Indeed, even if you deliberately saturate the exchange of a soil with H+, the acidity dissolves the soil minerals releasing aluminium which occupies exchange sites. So we never find H+ saturated soils. The reason for the high H+ levels reported is the use of inappropriate (and very out of date) analytical approaches. Without going into detail, we now recognise that the amount of cation exchange on a soil varies with the pH and the ionic strength (concentration) of the soil solution. As you increase either the pH or the ionic strength, the soil gets more


These laboratory observations of Rengasamy et al. (1986) have been confirmed in the field. In the on-farm trials of Schonbeck (2000), the poor hydraulic conductivity, crusting, and hardpans observed on these soils had often been attributed by the farmers to the cationic ‘imbalance’ of the soil. However, the reduction in the Mg-saturation from 18–28% to 11–21% had no effect on bulk density (compaction), moisture content, infiltration rate, or soil strength. In addition, the two soils that were the most ‘unbalanced’ (Mg 28%, Ca 59%) actually had the best physical properties.

Biological fertilityThe provision of ‘balanced’ cation ratios has been claimed to improve the soil’s biological fertility, and decrease weed growth and insect attack. Indeed, Albrecht (1975) stated that ‘more fertile soils prohibit insects’. However, comparatively little information is available comparing the biological fertility in ‘balanced soils’ to that in soils containing other cationic ratios. Nevertheless, in the trials of Schonbeck (2000), a reduction in Mg-saturation (from 18–28% to 11–21%) had no detectable effect on soil organic matter, biological activity, abundance of weeds, or incidence of disease or insect pest damage,

when compared to the control treatment. Similarly, Kelling et al. (1996) concluded that variation in the Ca:Mg ratio had no significant effect on the earthworm population or on the growth of weeds (grass or broadleaf).

How should a producer respond?• Wherethe‘science’isnotcomplete,predicting

benefits is hard or even impossible.• Yoursituationisunique.• Testtheproductyourself.• But test it properly – comparison with

established alternative; replication.• Donotfoolyourself.

All easier said than done, but how would you practically go about testing the effectiveness of a microbial inoculant designed to fix N or solubilise P? How would you ensure that you could draw valid conclusions – i.e. not fool yourself? Here are a few simple guidelines that might be useful in formulating your on-farm experiments.

Obviously, the work needs to be done in the field, with all the system buffering and spatial variability that brings with it. Replication is therefore essential, as is a random allocation of treatments to strips or plots. Strips are often

SAR 20

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Figure 7. Effects of the Ca:Mg ratio, sodium adsorption ratio (SAR), and salinity (presented as the total cation concentration (TCC, molc/L) on the relative hydraulic conductivity of a surface soil of a sodic red-brown earth (Rhodoxeralf). The relative hydraulic conductivity has been calculated separately for each TCC series. Data are from Rengasamy et al. (1986).


easier to manage, especially with GPS guidance systems are available. The important thing is to at least match the strip/plot width to that of your measuring or harvesting equipment, because that is the operation which needs to be easy to do (and do well) to measure the treatment effects. How many times have pasture or crop yields from strips not been collected because the harvest was rushed, or proved too difficult or laboursome to collect! If you cannot measure it, how do you expect to manage it.

The next thing to consider is your reference treatment or control, so that you can interpret the research findings. Ideally it should be something you do currently, and not a ‘nothing applied’ treatment (or not only a nothing applied treatment), as you are generally trying to prove the treatment is as good as, or better than, what you are currently doing (or cheaper). Every time produce leaves the farm, be it a truck load of beef, lamb, crop or wool, soil nutrition is driving out the gate and being removed from the farm. Monitoring that removal, and replacing it when required, is the only valid way of providing a truly sustainable and productive farming operation.

Also, be very clear about what you are trying to test, given the cautionary examples listed earlier. I think most people would accept that many of our current fertiliser use guidelines are best bet options, albeit based on experience gleaned from lots of trials and experience in different farms and soil types. That means that a low pre-plant soil N or P test does not guarantee you a fertiliser response. Make sure that you don’t just have two comparisons in your test – a current practice (e.g. your standard rate of starter P) and your biological alternative or treatment of interest. If they produce similar yields you will not be any wiser, as the product could be effective, or the site may not have been responsive in the first place. Having a nil P treatment in this case will sort that out.

Finally, do not leap in without giving the product a thorough test in different seasons and paddock conditions. People often question why science takes so long to be sure about something, but the earlier P. bilaii example shows that there will

be a range of outcomes with an average effect, and it is important to test often enough to get a realistic estimate of that average effect before you make a change.

Knowing if you are indeed responsive to a nutrient, or a combination of nutrients, is critical before you invest. Many, many dollars have been spent applying various products to paddocks and soils that do not have a deficiency, and thus have had not made any difference, except to the hip pocket. Do not be the next to do that again! Test, understand, and seek advice.

ReferencesAlbrecht, W.A. 1937. Physiology of root nodule bacteria in

relation to fertility levels of the soil. Soil Sci. Soc. Am. Proc. 2, 315–327.

Albrecht, W.A. 1939. Some soil factors in nitrogen fixation by legumes. Transactions of the Third Commission of the International Society of Soil Science, New Brunswick, New Jersey.

Albrecht, W.A. 1975. The Albrecht Papers: Volume 1 – Foundation Concepts. Acres U.S.A., Kansas City.

Albrecht, W.A., and T.M. McCalla. 1938. The colloidal fraction of the soil as a cultural medium. Am. J. Bot. 25, 403–407.

Amézketa, E. 1999. Soil aggregate stability: A review. J. Sustain. Agr. 14, 83–151.

Bear F E, Price A L and Malcolm J L 1945 Potassium needs of New Jersey soils. New Jersey Agricultural Research Station Bulletin 721.

Bear F E and Toth S J 1948 Influence of Ca on availability of other cations. Soil Sci. 65, 69–74.

Eckert D J and McLean E O 1981 Basic cation saturation ratios as a basis for fertilizing and liming agronomic crops. I. Growth chamber studies. Agron. J. 73, 795–799.

Edmeades DC (2000) ‘Science friction: the Maxicrop case and the aftermath.’ (Fertiliziser Information Services Ltd, PO Box 9147, Hamilton, New Zealand: Hamilton)

Edmeades DC (2002) The effects of liquid fertilizers derived from natural products on crop, pasture, and animal production: a review. Australian Journal of Agricultural Research 53, 965–976

Foy C D and Barber S A 1958 Magnesium deficiency and corn yield on two Indiana soils. Soil Sci. Soc. Am. Proc. 22, 145–148.

Gillman G P and Sumpter E A 1986 Modification to the compulsive exchange method for measuring exchange characteristics of soils. Aust. J. Soil Res. 24, 61–66.

Graham E R 1959 An explanation of theory and methods of soil testing. Missouri Agricultural Research Station Bulletin 734.

Gyaneshwar, P., G.N. Kumar, L.J. Parekh, and P.S. Poole. 2002. Role of soil microorganisms in improving P nutrition of plants. Plant Soil 245, 83–93.


Herridge, D.F., M.B. Peoples, and R.M. Boddey. 2008. Global inputs of biological nitrogen fixation in agricultural systems. Plant Soil 31, 1–18.

Hunter A S 1949 Yield and composition of alfalfa as affected by variations in Ca/Mg ratio in the soil. Soil Sci. 67, 53–62.

Jones, D.L. 1998. Organic acids in the rhizisosphere – a critical review. Plant Soil 205, 25–44.

Kelling, K.A., E.E. Schulte, and J.B. Peters. 1996. One Hundred Years of Ca:Mg Ratio Research. University of Wisconsin, Madison, Wisconsin.

Lambers, H., F.S. Chapin, and T.L. Pons. 2008. Plant Physiological Ecology. Second Edition. Springer, New York.

Lipman, C.B. 1916. A critique of lime-magnesia hypothesis. Plant World 19, 83–105 and 119–133.

Lynch, J.P., and M.D. Ho. 2005. Rhizisoeconomics: Carbon costs of phosphorus acquisition. Plant Soil 269, 45–56.

McLean E O, Hartwig R C, Eckert D J and Triplett G B 1983 Basic cation saturation ratios as a basis for fertilizing and liming agronomic crops. II. Field studies. Agron. J. 75, 635–639.

Rengasamy, P. 1983. Clay dispersion in relation to changes in the electrolyte-composition of dialyzed red-brown earths. J. Soil Sci. 34, 723–732.

Rengasamy, P., R.S.B. Greene, and G.W. Ford. 1986. Influence of magnesium on aggregate stability in sodic red-brown earths. Aust. J. Soil Res. 24, 229–237.

Schonbeck, M. 2000. Soil Nutrient Balancing in Sustainable Vegetable Production. Virginia Assocation of Biological Farmers, Floyd, Virginia. Available at: http://www.ofrf.org/.

Tandon, H.L.S. 1987. Phosphorus Research and Production in India. Fertilizer Development and Consultation Organization, New Delhi.

Tarafdar, J.C., and A. Jungk. 1987. Phosphatase activity in the rhizosphere and its relation to the depletion of soil organic phosphorus. Biol Fertil Soils 3, 199–204.

Orange (02) 6361 3000

Agronomists located at the following branches: Cowra Goulburn Mudgee

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The Pegala Pastoral Company − Vertically integrating cropping and beef production systems

M. Mason, Pegala Pastoral Company

Abstract: This paper describes the development and operation of a vertically integrated business that operates sheep, cattle and cropping operations across an aggregation of thirteen properties in the central Tablelands and North-West Slopes and Plains of NSW.

How did we get there?Necessity is the mother of all invention. Eight years of drought, poor commodity prices, high input costs and a growing fixed cost base meant that PPC needed to establish a business that was vertically integrated and producing good reliable cash flows.

Over that same eight-year period, beef prices had declined dramatically (especially the rates paid by Japanese owned feed-yards!), which also impacted feed-grain prices. This meant that PPC was adversely affected in two ways: reduction in prices for feed grains and beef. As a result, we came to the natural conclusion that we should value-add our grain by turning it into beef, without becoming a feedlot. Sounds simple – trust me it was not. After much trial and error we now have a system that works and is profitable. There is still room for improvement, but we are getting there.

Working out the production system was half the battle – we had to align ourselves with end users who were like minded and more importantly valued having a consistent reliable supplier of quality product and were prepared to pay for it.

Evolution of the grass and pastures management systemThe major hurdle faced by the southern farms over the past 10 years has been in relation to poor seasons. We have experienced eight dry winters in a row (Table 1). This fact has fundamentally changed our views as to which pasture best suits our system.

Excluding 2010 our average annual rainfall in the past few years was 639 mm (Table 1). Not bad, but when you consider that we did not receive the critical autumn break in the majority of those years we went into the winter with very little leaf

Key words: pasture-based grain assist program, sheep, cattle, cropping, tall fescue

Original Business ModelThe Pegela Pastoral Company (PPC) is a partnership that was formed by Garrick Hawkins and Mark Mason in 2001. The main aim of the business was to spread and reduce risk through geographic and enterprise diversity. This saw the company run cattle and sheep in the south, and grow crops on the northern farms. We owned the farms in the south, and leased the cropping country in north. In 2003, we purchased an additional two farms, one near the original southern farm and the other in the north near our leased cropping country.

Our business model was three-fold: 1. Sheep operations − build a flock of superfine

merinos that was fertile and productive.2. Cattle operations − buy in back-grounding

steers for feedlot markets. 3. Cropping operations − zero-tilled controlled

traffic, growing a wider variety of dryland crops both feed and human consumption.

Where we are todaySo from one property, the Pegela Pastoral Group is now an aggregation of thirteen properties spread across the central Tablelands and North-West Slopes and Plains regions of New South Wales (NSW).

Pegela Pastoral Company is a diverse business employing more than 40 people, turning-off over 40,000 head of slaughter cattle, shearing 15,000 sheep, cropping 16,000 hectares, with a state-of-the-art feed mill and a fleet of B-doubles.


area, and hence a severely reduced capacity to grow feed. This obviously adds weight to the old adage that timing is everything.

We have been working with Ross Yelland for the past 10 years and during that time we have gone the full circle from high performance Italian ryegrasses, and then back to Blackbutt oats to try to fill the winter-feed deficit.

Initially our focus was to maximise carrying capacity without sacrificing animal performance and we thought that we would be able to achieve this with a fescue-based pasture. Quantum, Resolute and Advance tall fescue were the main varieties utilised, as well as a proportion of high performance ryegrasses. The aim of the fescue was to fill the summer feed deficit, with the ryegrasses being used in winter. We supplemented this system with an application of single superphosphate – ~250 kg/ha/year. Our aim was to work towards all of our pastures being based on the newer fescue varieties available at the time (Resolute to fill the winter gap and Quantum to cover summer). We were very pleased with the initial results, although Resolute wasn’t as prolific in the winter as we probably would have liked.

Our initial results were fantastic. We managed to double our stocking rate to 15 dry sheep equivalents/ha and also saw healthy weight gains

in the cattle (1–1.3 kg/head/day), and wool cuts were up by half a kg per head. Then it stopped raining, or more importantly it stopped raining in the autumn and winter months. Success with our mix of varieties and species was very dependent on that autumn break.

We have received well below our 700 mm average for a number of years (Table 1) and like everyone else in central and southern NSW moved into survival mode. We have not had a substantial autumn break for several years, meaning we went into winter with very little leaf area on pasture plants giving them little hope of growing any feed through the cold winter months of June, July and August. Our high performance ryegrasses were anything but, providing modest value at best.

So, we went back to the future and started using oats again, firstly Blackbutt and then in the last two years Taipan, which we have been extremely pleased with.

We still had the problem of how we got our stock to the right weights to fit the markets we were attempting to service regardless of whether it rained or not. So, we hit upon the idea of value adding our grain by turning it into beef. Not a new idea and certainly been done by many before us. The problem was not many people have attempted to do it with the large numbers on a pasture-based grain assist program that we were running – so we set about reinventing the wheel.

Initially we thought we could achieve satisfactory gains through limit feeding and utilising the available pasture. This would have been okay had beef prices been stronger, but as you all know 2006–07 things were tough and like most things the profit was in the last couple of kilograms of rations not the first 5 kilograms.

Four years of trial and error later and we are achieving exceptional weight gains and producing a high quality product that is fully contracted to two major end users. We are able to run enough stock numbers to fully utilise our spring and autumn feed surpluses as well as continue to supply throughout the tougher winter and summer months. Animal production

Table 1. Annual and mean rainfall (mm) in 2001−10.

Year Annual total (mm)

2001 500

2002 592.5

2003 679

2004 860.5

2005 774.5

2006 406.5

2007 580

2008 709

2009 652.5

2010 1247

Mean values:

10-year rolling 700

Excluding 2010 639


remains consistent throughout the year, but ration intakes vary from 6–12 kg/head/day. Ration cost obviously varies depending on the year and season, but today you are looking at around 25c/kg (we grow about half of our total grain requirements) landed. It is also important to note that we transfer the price of our own grain internally between the enterprises at market values. Average weight gains range from 1.4 kg/day in winter to 1.7–1.8 kg/day in spring and autumn.

Stocking rates are consistent at around 2.5 beasts per hectare. Average time on farm is around 100 days. We have also found that this is the optimum time period required for us to hit the targets in terms of what our customer specify for fat cover, fat colour, saleable meat yields and carcass weights.

In terms of our sheep business, we have developed a very productive flock with adult fleece weights of over 5 kg of 16.8 micron wool. Our lambing percentage in the last couple of years has topped 100% and we have been able to get our wethers to boat weights. Sheep are not supplementary fed, except in drought times.

It is important to note that our system is equally reliant on good pastures as it is the ration that we make and feed out.

Where we are today is testament to the dedication and hard work of the people who work for the company. Our system is very intensive and certainly is not for everyone. It has required significant capital investment, which realistically is not available to the average farmer, but what it does show is that new ground can be broken and success can be achieved through hard work and perseverance no matter what business you are in.

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Factors affecting pasture production in variable landscapes – how does it influence fertiliser use and other management issues?

B. HackneyA, P. OrchardB, D. KempC, B. OrchardB

ADepartment of Primary Industries, Research Station Drive, Bathurst, NSW, 2795; BDepartment of Primary Industries, Pine Gully Rd, Wagga Wagga, NSW 2650;

CCharles Sturt University, Leeds Parade, Orange, NSW, 2800

Abstract: This paper reports on the results of a fertiliser response studies on the Central Tablelands and Monaro regions of New South Wales in variable landscape paddocks. Two sites were studied, one on the central Tablelands at Burraga, 80 km south of Bathurst and the second at Jimenbuen on the Monaro, 60 km south-west of Cooma. At each of these sites, fertiliser experiments were located at upper and lower slope positions on a north and south aspect. At both sites, without the addition of fertiliser, south slope positions in the landscape were significantly more productive than those on the north slope.

Three factors were found to alone or in combination, indicate whether specific areas of the landscape were likely to be responsive to fertiliser addition. These were identification of soil physical limtations, botanical composition limitations (particularly legume content) and soil chemical limitations. This study indicates that adoption of differential approaches to management of topographically diverse landscapes, particularly with respect to fertiliser addition and fencing is warranted.

Key words: phosphorus, aluminium toxicity, soil moisture

IntroductionIn Australia, the scientific community have relied heavily on the results of soil testing to indicate whether a pasture paddock is likely to be responsive to the application of fertiliser. In general, phosphorus (P) and sulfur limit pasture productivity and especially the growth of legumes, which are an important source of fixed nitrogen (N) (Whittet 1925; Donald 1965; Henzell 2007). Various models have been developed over time that predict optimum soil available P level where pasture production is unlikely to be limited. Refinements to these models have been made which take into account the P buffering index (PBI) and animal removal of nutrients from the pasture system (Gourley et al. 2007; Simpson et al. 2009).

Improved targeting of fertiliser use is becoming increasingly important with the rising cost of fertiliser and predictions that P-based fertiliser prices may double again within the next 10−15 years (van Kauwenbergh 2010). While some recent refinements to P requirement models are an important step in increasing the efficiency with which this resource is used, these models still assume uniformity in response to

application of fertiliser and there is little capacity for these models to take into account variation in landscape characteristics such as soil depth, moisture holding capacity and aspect. All of these factors can affect botanical composition and therefore the ability of pasture to respond to fertiliser addition. Simpson et al. (2009) have factored in some landscape characteristics of slope and its effect on nutrient loss into a P requirement model, based on New Zealand data. More fundamentally, all P requirement models are based on the ‘basal nutrient’ type of approach to determining P requirement. Traditionally, fertiliser requirement experiments also generally occur in botanically favourable well-balanced pastures, where topography is not variable. How applicable are such results in pasture paddocks where topography, soil type and pasture composition vary and how can we attempt to best manage these landscapes?

In New Zealand, there have been many experiments undertaken in variable landscapes to determine the extent of variation in pasture production and in some cases, response to fertiliser in topographically diverse landscapes (Radcliffe 1982; Gillingham et al. 1999). Studies have been undertaken to determine the impact of adopting a strategic approach to fertiliser application in these landscapes, which considers


landscape features and response potential. Such changes in management have revealed considerable benefits to overall farm profitability by adopting such management changes.

To date, there has been little research in Australia to determine how variable pasture production and response to fertiliser is in topographically diverse pasture paddocks. Some preliminary research by Hackney and Virgona (2001) on the south-west Slopes of New South Wales (NSW) demonstrated pasture production ranged from 300−9000 kg dry matter (DM)/ha in a topographically variable pasture paddock. Such differences in production potential indicate that the assumption of uniformity of pasture production and therefore response potential to applied fertiliser is likely to be flawed. This paper reports on the results of a fertiliser response studies on the central Tablelands and Monaro regions of NSW in variable landscape paddocks.

Research site locations and designTwo sites were studied, one on the central Tablelands at Burraga, approximately 80 km south of Bathurst and the second at Jimenbuen on the Monaro, approximately 60 km south-west of Cooma. At each of these sites, fertiliser experiments were located at upper and lower slope positions on a north and south aspect [referred to as north upper (NU), north lower (NL), south upper (SU) and south lower (SL)]. At each position in the landscape, single superphosphate was applied at rates equivalent to 0, 10, 20, 40, 60 and 80 kg P/ha each year for three years. Long-term average annual rainfall at the Burraga site was 830 mm. Over the years of the experiment (2001−03) rainfall was 89, 77 and 87% of the long-term average. At Jimenbuen, long-term average annual rainfall was 560 mm and over the years of the experiment it was 110, 95 and 84% of the long-term average.

The sites chosen were native perennial grass based pastures typical of those found in each respective region. The central Tablelands site was a microlaena – (Microlaena stipoides) based pasture while the Monaro site was a spear grass – (Austrostipa bigeniculata) based pasture.

At both sites, subterranean clover (Trifolium subterraneum) had been introduced some 30 years earlier during the so-called ‘sub and super’ era of pasture improvement. Varieties of subterranean clover present at the sites included Mt. Barker and Woogenellup. Both sites were acidic with pH at the Burraga site ranging from 4.4−4.8 across landscape positions. At Jimenbuen, pH ranged from 4.6−4.8 across landscape positions. Aluminium as a percentage of total cation exchange capacity ranged from 8−22% across landscape positions at the Burraga site, and from 4−10% at the Jimenbuen site.

Pasture composition and herbage was assessed using the Botanal technique (Tothill et al. 1992) 15 times at the Burraga site over three years and 14 times over three years at the Jimenbuen site. Herbage samples were cut and removed after each assessment.

Results While the pasture paddocks used in this study were considered to be based on native perennial grasses and an annual, exotic legume, the composition differed significantly across the sites at the commencement of the study (Table 1). In general, the legume component of the pasture was significantly lower on north aspect positions. At the Burraga site, the native grass frequency was significantly lower at the NU position compared with all other positions in the paddock. At Jimenbuen, the highly drought tolerant spear grass was present at higher frequency on the north slope while remnant cocksfoot (Dactylis glomerata), a result of pasture sowing in the 1970s, as found only at south slope positions.

Pasture production and fertiliser responseOver the three years of the study, cumulative pasture production ranged from 18.4−31.7 tonnes (t) DM/ha at Burraga and 15.8−19.8 t DM/ha at Jimenbuen, respectively (Figure 1). At both sites, without the addition of fertiliser, south slope positions in the landscape were significantly more productive in terms of total


herbage production and legume production, than those on the north slope. (Hackney 2009).

At the Burraga site, despite all positions at both sites having soil available P levels which would indicate they should be responsive to P application, only three of the four positions showed increases in pasture production with addition of fertiliser (Figure 1). At Jimenbuen, only one of the four positions was responsive to the application of fertiliser.

Again at the Burraga site, where responses to application of P occurred, the response was due solely to an increase in legume production, while at Jimenbuen the increase was due to a combination of increased production from both legumes and cocksfoot (data not shown). The increase in pasture production at the Burraga site occurred in spring of all three years and in autumn in the final year of the study. At Jimenbuen, pasture production increased with use of fertiliser only in spring and only in the first year of the study, when seasonal conditions were wetter than average.

Why was pasture production and composition so variable and why were some positions unresponsive to fertiliser application despite having low initial available soil P?Solar radiation was measured on the north and south slope at both sites. Solar radiation over the period of the study was 8 and 5% higher on the north, compared with the south slope at the Burraga and Jimenbuen sites, respectively. As a result, soil temperature was generally higher for north slope positions. While it might seem that higher soil temperatures would be more favourable for pasture growth, it also means that soils dry out more quickly. At the north slope positions, measurements taken over the duration of this study showed that these landscape positions were either consistently drier and/or had more erratic wetting and drying patterns meaning that sustaining long periods of pasture growth was less likely. Consistency of moisture availability is particularly important for shallow-rooted species such as the annual legumes found at these sites. At both Burraga

and Jimenbuen, annual legumes contributed more to overall pasture production on the south slope positions, without fertiliser addition than on the north slope positions and it is likely that the less consistent soil moisture conditions had contributed to lower populations of legumes at north slope positions. Despite both paddocks having had subterranean clover sown introduced uniformly across the paddocks decades ago, populations were lower on the north slope, particularly at Jimenbuen than on the south slope. Similar results have been reported in New Zealand studies. An adequate legume population is essential in realising an increase in pasture production in response to P fertiliser addition. Grasses will respond to application of P fertiliser, but only up to the limit of N availability (Wilson and Haydock 1971).

Nutrient responsive locations had moderate to high initial populations of legumes (Table

Phosphorus application rate (kg P/ha)

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SU=0.14X+27.4

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LSDslope=0.067

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LSDslope=0.030

(a) Burraga

(b) Jimenbuen

Figure 1. Cumulative herbage production over three years at north upper (NU), north lower (NL), south upper (SU) and south lower (SL) slope positions at various rates of P application (applied as single superphosphate) at (a) Burraga and (b) Jimenbuen.


1). However, legume content alone did not indicate whether or not a location would be responsive to fertiliser addition. The SL position at the Burraga site had good legume content, but did not respond to fertiliser addition. This location, however, did have the highest level of exchangeable Al (22%). Evans et al. (1988) reported decline in subterranean clover herbage production when exchangeable Al exceeded 15% of total cation exchange capacity (CEC). High levels of Al impact directly on root development preventing cell division at the root tips resulting in stunting of the root system. This in turn affects the ability of the plant to harvest nutrients and moisture, thereby restricting growth. Further, low pH – high exchangeable Al soils reduce the survival of the rhizobia responsible for nodulation of subterranean clover (Munns 1968; Burnett et al. 1994). Without adequate nodulation, legumes fail to fix N for use by non-leguminous pasture plants and therefore there is limited capacity to respond to applied P. It is possible that high levels of Al affected legume growth at the SL position at the Burraga site and therefore restricted response to P application. Interestingly though, an additional fertiliser treatment consisting of lime (2.5 t/ha) applied in combination with 80 kg P/ha did not significantly increase overall total pasture

or legume production compared with the nil P treatment. Another possibility is that under low pH – high exchangeable Al conditions at the SL position, rhizobium survival had declined over time, resulting in poor or ineffective nodulation of the subterranean clover and therefore limited N fixation, restricting N available to non-leguminous pasture components and limited ability to respond to applied P.

What are the implications of the findings of this study for fertiliser management in the future?This study has found that pasture response to fertiliser application differed significantly across variable landscapes. In the paddocks used in this study, previous management had attempted to create greater uniformity in pasture composition through the introduction of annual legumes and at Jimenbuen, through the sowing of the perennial grass cocksfoot some 30 years earlier. Over the intervening period since the legume and/or perennial grass introductions, pasture composition had diverged resulting in distinctly different pasture communities based either on an aspect or within aspect basis. This was most apparent at the Jimenbuen site where cocksfoot was found only on the south facing aspect and

Table 1. Soil chemical, soil physical and botanical composition at north upper (NU), north lower (NL), south upper (SU) and south lower (SL) slope positions at the Burraga and Jimenbuen sites at the commencement of the study.

NU NL SU SL l.s.d (P =0.05)

Burraga Available PColwell 3.3a 7.5ab 11bc 14c 4.5

Phosphorus buffering index 55 29 62 30

Al (% total CEC) 18b 10a 8a 22c 3.6

Coarse particle fraction 0–80 cm (%) 62 22 29 7.0

Subterranean clover frequency (%) 17a 20a 67b 38ab 40

Native perennial grass frequency (%) 39a 65b 65b 65b 14

Jimenbuen Available PColwell 15b 15b 10a 10a 3.0

Phosphorus buffering index 60 61 42 42

Al (% total CEC) 4.0a 10b 6.0a 8.0b 1.7

Coarse particle fraction 0–80 cm (%) 55 41 48 69

Subterranean clover frequency (%) 10a 45b 100c 100c 20

Native perennial grass frequency (%) 45c 40bc 26a 31ab 12


subterranean clover populations were higher on the south than the north facing aspects. Differences in microclimate, particularly moisture availability, or more specifically the consistency of moisture availability have probably been partially responsible for the differences observed in current plant communities across the sites. Overlaying this of course is the impact of grazing. In landscapes such as those used in this study, it is difficult to manage grazing for uniformity of pasture utilisation. Thus, areas of such paddocks may be under- or over-utilised which, over time results in plants tolerant of heavy grazing (those with low growing points and/or short life cycles) dominating in heavily grazed areas, while different communities are formed in less utilised areas. The results presented here show that predicting fertiliser responses is problematic, unless other factors are taken into account. How then do we attempt to best manage these landscapes?

In terms of managing fertiliser application, the results of this study have identified three key parameters which will assist in identifying areas capable of responding to P fertiliser addition:1. Assess any soil physical limitations in

the landscape – this will involve looking at soil depth and soil texture. Deep soils are capable of maintaining longer periods of pasture growth as they have the capacity to hold more moisture than shallow soils. Similarly, coarse textured soils will have less capacity to hold moisture than those with a finer texture. Assess whether the soil at different points in the landscape have any other physical limitations. For example, are there areas of landscape where the soil becomes waterlogged, thus restricting pasture growth.

2. Assess the current composition of the pasture – it is particularly important to be able to assess the legume content of the pasture. If legume content is lacking at specific areas in the landscape, then the capacity of that area to respond to application of P fertiliser will be limited. Certainly, botanical composition can be altered by introducing legumes into legume deficient pastures. However, assessment of pastures in

their current state will give a good indication how position in the landscape has influenced the pasture composition. This may also give an indication of how successful introducing species such as legumes into the landscape may be.

3. Assess possible soil chemical limitations at locations in the landscape with favourable soil physical and botanical composition characteristics – often this is the first component considered in deciding whether or not to apply fertiliser to a pasture. However, unless soils have the ability to maintain good levels of moisture for prolonged periods and thus support a pasture with composition capable of responding to fertiliser application, then the worth of applying fertiliser needs to be questioned. It is also important to look further at soil tests than simply the level of available P. In many Tableland soils, Al toxicity is common. Where levels of exchangeable Al exceed 15% it is likely that subterranean clover production is being restricted either through root stunting and/or by reduced survival of rhizobia and therefore reduced nodulation and N fixation. There may be capacity to address surface acidity/Al toxicity through surface application of lime, however, be aware that the rate of amelioration using surface application is slow in comparison with incorporation. Additionally, consideration may need to be given to the reintroduction of rhizobia as it may have been reduced to negligible levels in the previously low pH – high Al conditions. Results from Western Australia have shown significant increases in old established subterranean clover pastures where rhizobia levels are deliberately increased through addition of inoculant.

If these three factors are considered, then it may be possible to implement a differential approach to fertiliser application – applying fertiliser only to areas with good moisture holding capacity and botanically favourable composition. Certainly, such an approach can significantly reduce expenditure on fertiliser – an important consideration for future farming practices, given the predicted increase in world fertiliser


prices (van Kauwenbergh 2010). However, the effectiveness of such an approach in isolation will depend on the ability to utilise the additional pasture growth achieved. In highly variable landscapes, livestock are highly preferential in their grazing habits and the period of time they spend in specific areas of the landscape can be greatly influenced by weather conditions, as well as the species and breed of the grazing animal. Ultimately, the relative success, economic and/or environmental, of adopting a differential approach to input management, particularly with regard to fertiliser use, will depend on the ability to control grazing behaviour.

ReferencesDonald CM (1965) The progress of Australian agriculture

and the role of pastures in environmental change. Australian Journal of Science 27(7), 187–198.

Gillingham AG, Maber J, Morton, J Tuohy M (1999) Precise aerial fertiliser application on hill country. Proceedings of the New Zealand Grassland Association 61, 221–226.

Gourley C, Melland A, Waller R, Awty I, Smith A, Peverill K, Hannah M (2007) Making Better Fertiliser Decisions for Grazed Pastures in Australia. (Victorian Government Department of Primary Industries, Victoria)

Hackney BF (2009) Understanding and Managing Variation in Pasture Growth in Topographically Diverse Landscapes. (PhD Thesis: University of Sydney)

Hackney B, Virgona, J (2001) Towards improving the efficiency of fertiliser use in variable landscapes. In ‘Proceedings of the 16th Annual Conference of the Grassland Society of NSW, Gundagai’. pp. 80–81. (Ed K Condon).

Henzell T (2007) Australian Agriculture: its History and Challenges. (CSIRO Publishing, Melbourne)

Radcliffe J (1982) Effects of aspect and topography on pasture production in hill country. Proceedings of the New Zealand Grassland Association 33, 91–104.

Simpson R, Graham P, Davies L, Zurcher E (2009) Five Easy Steps to Ensure you are Making Money from Superphosphate. (CSIRO Plant Industries and Industry & Investment NSW)

Van Kauwenbergh SJ (2010) World Phosphate Rock Reserves and Resources. (International Fertilizer Development Centre (IDFC); Alabama, USA)

Whittet JN (1925) Top-dressing pastures. Agricultural Gazette 225–245.

Wilson, JR and Haydock KP (1971) The comparative response of tropical and temperate grasses to varying levels of nitrogen and phosphorus. Australian Journal of Agricultural Research 22, 573–87.

The Efficient Advantage


Landscape and grazing management affects on pasture production and persistence on “Dunns Plains”

B. Townson

“Dunns Plains”, Rockley, NSW 2795

Abstract: “Dunns Plains” covers approximately 2600 ha with an elevation ranging from 800 to 1000 m (average annual rainfall 700 mm). The past 10 years have been a challenge with the light and variable rainfall. The overall livestock policy includes self-replacing breeding flocks and herds which are supplemented with trading stock as seasons and markets allow. The different landscapes that occur on the three dominant soil types (light shale, red basalt, and heavy black basalt) are described. In the early 2000s, the average June stocking rate on “Dunns Plains” was around 9 dry sheep equivalents (DSE)/ha, but this has reduced to around 7 DSE/ha over the past decade.

Key words: native pastures, improved pastures, sheep, cattle, variable rainfall

IntroductionSince 1989 “Dunns Plains” has been owned and operated by John Fairfax. It is located at Rockley, 40 km south of Bathurst and covers approximately 2600 ha with an elevation ranging from 800 to 1000 m above sea level. The average annual rainfall for the area of 700 mm tends to be evenly distributed throughout the year.

In August 1996, I took on the position of managing the property. My aim was to further improve pastures and to increase stocking rates in a sustainable fashion. This I hoped to do with the use of fertiliser, weed control, and fodder conservation via hay and silage production. A lot of the pastures were in good shape when I arrived; however, the fences needed a little work to adopt suitable grazing management. In 1997, we planned to sow three paddocks to new pastures which turned out well despite it being a very dry year. This result was due mainly to good weed control the previous spring. For the next three years, we had average rainfall and were able to conserve a lot of fodder.

The past 10 years have been a challenge with the light and variable rainfall. From 2000 to 2010, average annual rainfall has been around 600 mm per annum, 100 mm below the long-term average. However, 2010 was the wettest year on record with 1100 mm.

The overall livestock policy being undertaken at “Dunns Plains” includes self-replacing breeding

flocks and herds which are supplemented with trading stock as seasons and markets allow. Breeders are maintained at moderate levels and in the event of a serious extended dry period, numbers are reduced to allow maintenance of ground cover. In maintaining this policy, the operation is not exposed to restocking with often expensive and lower quality breeding animals with poor age structure.

We are currently running 650 Angus cows and 300 heifers which calve in spring, as well as 4200 crossbred ewes, which lamb in autumn and spring. Most of the steer calves are sent to our other property near Cootamundra to be grown out to heavier weights. Also, some store lambs are sent to Cootamundra as we have found it to be better country for lamb finishing.

The property has three different types of landscape that are associated with three dominant soil types (Figure 1). The three main soil types may be described as being light shale, red basalt, and heavy black basalt. Most of these soils have a pH of 5.0−5.5 (CaCl2) and, with the exception of the light country, the rest of the farm has a good history of superphosphate application.

Light shaleThe country dominated by light shale soils represents about 500 ha, and is located on the higher slopes up to 1000 m elevation and is quite steep in places. It is very fragile and prone to erosion, so it is important to avoid overgrazing or ground disturbance.


Typical native pasture species on this country are Microlaena, wallaby, spear grass and kangaroo grass. Microlaena tends to be the most productive species as it stays green all year round and forms a carpet which reduces erosion. In the past, this area of the farm was used for wool production through the running of Merino wethers. They have been unprofitable, so we now graze these areas with dry ewes and occasionally cows.

Five years ago we received grant money from the Upper Macquarie Catchment Management Authority to split a 300 ha paddock into four paddocks, so that we could better manage them. They are now grazed on a rotational basis to better maintain ground cover. I try not to let ground cover get below 70% and to allow them to reseed over summer at least every second year. Since subdivision there has been a slight increase in ground cover, but there has also been an increase in the presence of the weed biddy bush (Cassinia arcuata). This will be controlled with the use of chemicals. Because of the elevation and the species present in this part of the landscape, grass growth in winter is very low, and hence not much grazing happens during this time of the year.

With careful grazing management there is no reason why these pastures cannot be sustained indefinitely. The soil type here is poor and it doesn’t justifying spending money on soil fertility or pasture improvement, as the return would be little. An additional problem to managing these areas is that there are also large populations of kangaroos here.

Red basalt soilsThese represent about two-thirds of the farms area (1800 ha), and in the past have been sown down to introduced pasture species, mainly phalaris, cocksfoot and subterranean clover. There is also a lot of spotted medic found in pastures throughout this region of the landscape. Elevations range from 850 to 900 m. This part of the landscape has had a good history of single superphosphate application with phosphorus (P) levels ranging from 15 to 50 ppm Colwell. The Phosphorus buffering index (PBI) is around 70, which means we need to get our P levels above

30 ppm Colwell. Pastures on these soils respond quickly to rainfall, providing temperature is not limiting. Grazing management of these areas follow a pattern of being set stocked during calving and lambing, which occurs in winter and spring, respectively. For the remainder of the year, stock are moved according to feed availability. Because of the kinder environment of the Tablelands, the persistence of pastures has been very good, with some pastures sown 40 years ago and still as good, if not better than when they were sown.

Even though we have had ten fairly dry years, I have tried to maintain at least 50% ground cover by resting and reducing stocking pressure. Now that we have had a good rainfall year the pastures have responded very well, in fact pasture growth has been too good and phalaris pastures have got out of control. They have received some heavy grazing over summer and autumn to get the fresh new growth to come through for this growing season.

Heavy black basaltThe area covered by heavy black basalt soils is about 300 ha and is restricted to the lower areas of the farm at about 800 m elevation. About 100 ha is sown to lucerne which is used for finishing or value adding lambs. The rest is dominated by phalaris, cocksfoot and subterrenean clover. These areas are very productive, especially in spring and summer. They are capable of carrying around 30 dry sheep equivalents (DSE)/ha at this time, with growth rates up around 80 kg/ha/day. However, the soils do take a lot of rain to really fire up, but once wet they hold on well. In wet years, it is important not to let these areas get out of control as the pastures become rank and of little value. Disadvantages of this area include that it is slow to respond to rainfall, and in winter, are subject to severe frosts with temperatures frequently down to –10oC.

One of the best ways to control pastures in this area of the landscape is through fodder conservation. We attempt to make at least 500 big square bales of silage and 300 round bales of hay each year. The silage is stored in underground pits as long term drought reserves.


To maintain stocking rates there is usually some supplementation required during winter. Cattle are fed hay or silage and sheep grain, which is brought in from the Cootamundra property.

Stocking ratesIn the early 2000s, our average June stocking rate was around 9 DSE/ha, but has reduced to around 7 DSE/ha over the past decade. Stock numbers have changed over the past few years due to three main factors. Firstly, a change in the enterprises running on “Dunns Plains” from Merino wethers to increasing cattle numbers and first-cross ewes (both of which require a higher condition score to be maintained). Secondly, a run of drier than usual years forced us to reduce stock numbers. Thirdly, a move to finishing more lambs on “Dunns Plains” rather than selling as stores. In combination, these changes have caused a reduction from a peak of over 23,000 (June) DSEs down to the current level of around 18,000 DSEs (Figure 2).

Even though 2010 was a very wet year we have not had a chance to build up our numbers and we chose not to buy in stock, due to the narrow margins available with trading. Even though stock numbers have been down, an increase in livestock prices has compensated for reduced production and the business has still been very profitable. If the seasons trends back to normal, we will increase stock numbers, but not to the detriment of the pastures.

Summary of grazing managementNative pastures on the high country and lighter soils are grazed rotationally to a point where there is not less than 70% ground cover. Pastures are then rested in late spring and early summer, and allowed to seed at least every second year. They are usually grazed with dry stock and very little fertiliser has been applied on this country. This management still seems to be maintaining a good cover of valuable natives without the invasion of too many weeds.

The improved pastures on the red country receive at least 125 kg/ha of single superphosphate every second year, with molybdenum applied with the superphosphate every fifth year. This

program has maintained good clover content at around 40%, which is crucial to good grass growth. Grazing in these areas varies according to livestock needs and ground cover, but tends to be set stocked over calving and lambing and then rotational for the remainder of the year. There is no set rotation; stock movements are adjusted according to stock needs, feed availability, and ground cover. Rotations are carried out on a simple basis with only minor subdivision and water improvements being undertaken.

The lower country management is similar to the red country, except where lucerne has been sown. Lucerne requires special management if you want it to persist. It likes to be grazed hard for short periods and then rested. The rest period will depend on regrowth, which in turn depends on rainfall and temperature. This basic principle of lucerne grazing management is applied at

0

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1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Tota

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Figure 1. Typical landscape diversity on “Dunns Plains”. Foreground shows typical native pastures on light shale, mid-ground shows areas of intensive production on heavy black basalts and background shows areas of intermediate to high production on red basalts.

Figure 2. Change in total stocking rate (total June DSEs) on “Dunns Plains”.


“Dunns Plains”, with lucerne pastures lasting at least 10 years.

ConclusionsI think our grazing management must be working as the pastures on “Dunns Plains” are in a good state despite the fact we have had 10 years of lower than average rainfall. The key management factor I think is that you have to be flexible and have a plan to cope with the variability of seasons. A wise man once said to

me that you should always have some animals on the farm you don’t like, that way, if the season dries off, you do not have trouble selling these animals. In our case, it now tends to be the older animals.

The future challenges faced by “Dunns Plains” are dominated by rainfall and its timing. This will always be a major factor affecting the decisions made. However, government policy may play an important role, in particular, with the introduction of a carbon tax.

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Collaborate to survive and thriveJ. Gladigau

“Bulla Burra”, Alawoona, SA; [email protected]

Abstract: Over the past three years John and his wife Bronwyn, along with another local farming family, have been involved in the creation of their first collaborative farming venture. “Bulla Burra” is the merged entity of the two former farming businesses, which in its third season in 2011 will plant 8000 ha to wheat, barley, triticale, rye, canola and mustard. John is excited about the future potential of their new farming model as a means to build long-term profitability and sustainability for the agricultural sector while retaining the integrity and heritage of family farms and the fabric of local communities.

Key words: investment, business structure, business model

John Gladigau and his wife Bronwyn own a 2000 ha property at Alawoona in the northern Mallee region of South Australia. They have two children, Jayden (13) and Aimee (9). In 2006, John was awarded a Nuffield Scholarship, sponsored by ABB Ltd, to study collaborative ventures around the world. In 2007, he travelled to the USA, Canada, New Zealand, Mexico, Brazil, the United Kingdom and Europe gaining a global perspective on the future of agriculture and visiting many businesses involved in collaborative arrangements which were creating long-term benefits for all involved.

Over the past three years John and Bronwyn, along with another local farming family, have been involved in the creation of their first collaborative farming venture. “Bulla Burra” is the merged entity of the two former farming businesses, which in its third season in 2011 will plant 8000 ha to wheat, barley, triticale, rye, canola and mustard. John is excited about the future potential of their new farming model as a means to build long-term profitability and sustainability for the agricultural sector while retaining the integrity and heritage of family farms and the fabric of local communities.

There is no doubt that collaboration in any form of business makes a great deal of sense, especially in agriculture. At a time when our terms of trade are diminishing it is widely documented that farmers globally are overcapitalised beyond what a successful business can reasonably sustain into the future. They are also being stretched in their business and agronomic expertise, and are

developing businesses which are being funded by capital growth due to high land prices, rather than return on investment.

The fact that so little collaboration occurs between grass roots farmers, especially in Australia, has more to do with our fierce independence, some lack of understanding of business fundamentals, scepticism of being ‘ripped off ’, and the emotion attached with long-term family farm ownership. Though collaborative ventures can be fraught with danger, mainly due to the emotions and personalities of the individuals involved, much of these can be mitigated by having a comprehensive business plan with well documented entry and exit clauses for all concerned.

Though there are not the government or industry incentives for collaborative ventures in Australia as there are in countries like the United Kingdom, I believe there are advantages available to farmers through the full utilisation of capital and resources, marketing and value adding opportunities, purchasing of inputs, sharing of labour resources and expertise, and the full business and financial accountability such a venture brings.

A study of collaborative models from around the world has led me to conclude the following:• Thereisanenormousamountofinvestment

money currently looking for a home in agricultural ventures, including within Australia. Such ventures need to be structured in such a way that they can be scrutinised alongside other industry and investment sectors.

• Businessesneedtobeable todifferentiatebetween real estate and agribusiness, and



if necessary separate the two to maximise performance.

• There areno set rules onhowabusinessmodel can be set up, outside of the laws and regulation by which you are governed. There are many entrepreneurial structures which can be designed to share risk and reward between parties for the benefit of all, including flexi-leases and share farming options.

• Allcollaborativeventuresneedtobesetupwith the notion of win–win in mind.

• Successful,large-scalebusinessescreatecellsof optimum efficiency and profitability, and replicate them.

• Thetwogreatestthreatstothesuccessofanycollaborative venture are the emotions and personalities of the parties involved.

I believe collaborative farming ventures, or the notion of running several family farms under a single business structure, has a huge amount of potential in Australia. We are not restricted by agricultural policies which create disincentive for cooperation and are in a time in history where, with the biofuels revolution, and a volatile local grains industry, we are in a position to make a significant contribution to the agricultural development of our nation. We can do this through the creation of business models which not only make our properties more profitable and sustainable, but also preserve their integrity and heritage for generations to come. In this way, not only will it allow a lot of currently unviable businesses to survive, but with the opportunities available, the potential to thrive.

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Grassland 2.pdf 1 20/06/2011 3:02:14 PM


NSW Hay and Silage Feed Quality Awards 2011Following the success of the competition at last years conference producers across New South Wales were again invited to enter a Hay and Silage Feed Quality Competition with awards presented at the conference dinner.

The aim of this competition was to promote the benefits of high quality hay and silage to all farmers with emphasis on the importance of feed quality in animal production and how to achieve feed quality in conserved forages.

Awards were based on feed quality analysis results from the NSW DPI Feed Quality Service with emphasis on metabolisable energy and crude protein.

Results can be compared with guidelines provided in NSW DPI Silage Note 4 (www.dpi.nsw.gov.au) and TopFodder Successful Silage manual.

Awards compared hays and silages in each category i.e. one award for each crop or pasture type, not separate awards for hay and silage.

Samples were representative and must have come from commercial lot size intended for feeding to animals. Minimum lot size 5 tonnes of product.

Samples were to be of forage (hay or silage) conserved and/or fed in 2010/2011

Categories for awards were: Sponsor

Overall winner best conserved hay or silage Integrated Packaging

Winter/temperate pasture New Holland

Summer/tropical pasture New Holland

Winter crop New Holland

Maize Pioneer Hi-Bred

Other summer crop New Holland

Lucerne New Holland

Other New Holland

We thank the sponsors of these awards:

NSW Feed Quality Service

$5000 worth of prizes

http://www.dpi.nsw.gov.au


Cereal based forage crops for hay and silage productionJ. PiltzA, C. RodhamA, J. WalkerB, P. MatthewsC, B. HackneyD and J.F. WilkinsA

AEH Graham Centre for Agricultural Innovation (Department of Primary Industries and Charles Sturt University), Wagga Wagga Agricultural Institute, Wagga Wagga, NSW, 2650;

[email protected]. BDepartment of Primary Industries, 602 Olive Street, Albury, NSW, 2640. CDepartment of Primary Industries, 161 Kite Street, Orange, NSW, 2800.

DDepartment of Primary Industries, Bathurst Primary Industries Institute, Bathurst, NSW, 2795.

Abstract: Cereal and cereal/vetch forage crops were grown at Culcairn, New South Wales (NSW) in 2009 and Temora, NSW in 2010 to evaluate yield and quality when harvested at the boot, anthesis (flowering), milk and soft/mid dough stage of cereal development. Annual rainfall at the sites was 377 mm in 2009 and 736 mm in 2010. Average yield (tonnes (t) dry matter (DM)/ha), Metabolisable Energy (MJ/kg DM) and crude protein (%) content were 6.61, 10.45, 12.0 and 21.08, 9.41, 14.76 in 2009 and 2010, respectively. Metabolisable Energy content of crops was higher in 2009 compared with 2010 and declined more slowly with maturity. Cereal/vetch mixtures had significantly (P <0.001) higher crude protein content than cereal only crops which was reflected in a positive improvement in predicted liveweight gain for weaner sheep and cattle.

Key words: cereal, vetch, forage, maturity, metabolisable energy, protein content, yield

IntroductionProduction of beef and sheep meat is reliant on the supply of adequate nutrition for both breeding and finishing animals. In Australia, livestock production from grazing is restricted by seasonality of pasture growth and quality. Across southern Australia pasture growth occurs predominantly in spring with autumn production significant in some areas and in some years. In winter, pasture quality is usually high but availability is low whereas in summer there is residual dry standing pasture available but forage quality is only moderate; later in the season there is a further decline in quality combined with a decline in availability. Producers feed grazing livestock supplements of hay, silage, grain and/or meals to provide the additional energy (and crude protein, CP) required for maintenance and production.

Many areas of southern Australia are very suitable for growing cereal and cereal/legume forage crops which can be conserved for either hay or silage to supplement grazing livestock at a later date. Cereals are high yielding and of moderate to high quality depending on maturity at harvest. Growing cereals with a legume is a management option to ensure adequate crop protein content

and ameliorate any decline in digestibility that occurs with increasing maturity at harvest. However including a legume can reduce yield. This paper will present results from two experiments that were conducted across southern New South Wales (NSW) at Culcairn in 2009 and Temora in 2010 to evaluate the yield and quality of cereal and cereal/vetch forage crops grown for conservation as either hay or silage.

Materials and methodsSeven cereal varieties were selected to provide a cross section of types grown in southern NSW and were either grown as a monoculture or in a mixture with popany vetch (Vicia benghalensis). The cereal varieties were Tobruk triticale, two wheats Strezlecki (grain only) and Wedgetail (dual purpose), two barleys varieties Gairdner (malting) and Urambie (dual purpose), and two oats varieties Echidna (grain) and Mannus (dual purpose). The crops were sown at 70 kg/ha cereal or 15 kg/ha cereal plus 60 kg/ha vetch in the mixtures, at 15 cm row spacing. MAP fertiliser at the rate of 105 kg/ha was applied at sowing. There were three replicates of each treatment.

Samples from each plot were cut, approximately 5 cm above ground, by hand at the boot, anthesis (flowering), milk and soft/mid dough stage of cereal grain development. None of the plots were taken to maturity for cereal grain harvests.



A subsample was dried at 80ºC for 24 h to determine dry matter (DM) content. Botanical composition was determined for the vetch and cereal mixes. Metabolisable Energy (ME) content (MJ/kg DM) was determined by NIR.

Growth rates and intake for 300 kg British breed steers and 30 kg crossbred wethers were predicted using Grazfeed (version 5) based on estimated feed quality (ME and CP) data and assuming ad libitum intake of the forage as the sole diet. Expected value ($) of livestock production of these crops was calculated assuming that only 50% of the forage was conserved and further losses/wastage reduced production by 20%.

Results and discussionSeasonal conditions varied markedly between 2009 and 2010. At Culcairn in 2009 the total annual rainfall at was 377 mm which was only 64.4% of the long-term average (586 mm) whilst in 2010 Temora received 736 mm, which was 40.5% above average (524 mm). A number of the later maturing plots from both experiments were not harvested; in 2009 the continuing drought led to the early senescence of a number of plots in each experiment, whereas in 2010 the wet conditions combined with high yields caused lodging and disease.

YieldAt Culcairn in 2009 the dry conditions limited yield which averaged 6.59 tonnes (t) DM/ha across all crops and harvests. The final harvest of the triticale/vetch and wheat/vetch plots was abandoned because the crops, especially

the vetch component, had senesced. Yield differed (P <0.001) among cereal varieties and increased (P <0.001) with harvest with average yields of 5.54, 6.72, 7.04 and 7.40 t DM/ha at the boot, anthesis, milk and dough stage harvests, respectively. When averaged across all cereal varieties and harvests there was no difference in yield between cereal only and cereal/vetch crops, however the effect of vetch inclusion did vary (P = 0.002) with cereal variety (Figure 1). When averaged across harvests the inclusion of vetch increased yield for Strzelecki, but reduced yield on Tobruk and Wedgetail.

Cereal variety

Echidna Mannus Urambie Gairdner Wedgetail Strezlecki Tobruk

Yiel

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Figure 1. Effect of cereal variety and vetch inclusion on yield (t DM/ha) of cereal and cereal/vetch crops grown at Culcairn, NSW in 2009. Mean across all harvests. Note: yield estimates for Wedgetail and Strzelecki include predicted values for the final harvest of Wedgetail/vetch and Strzelecki/vetch crops. Only one plot of Tobruk/vetch was harvested at the dough stage.

Yield of both the cereal (P <0.001) and vetch (P = 0.003) component of the cereal/vetch crops was affected by cereal variety and yield of vetch increased (P = 0.012) with harvest whereas that of cereal did not (Figure 2). When compared

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Figure 2. Effect of cereal maturity at harvest on the yield of the cereal and vetch components of cereal/vetch crops grown at Culcairn, NSW in 2009.


with the other cereal varieties Mannus had the lowest vetch yield at all harvests. Echidna had the second lowest vetch yield at the boot harvest and the highest cereal yield at all harvests, except milk stage when Mannus had the highest cereal yield.

Growing conditions at Temora in 2010 were markedly different and yield was not limited by moisture content. This was reflected in substantially higher yields, which averaged 21.1 t DM/ha. As was the case in 2009 yield varied with cereal variety (P <0.001) and increased (P <0.001) with harvest. In contrast to 2009 however yields were lower on plots containing vetch. There were also significant interactions between cereal variety, vetch treatment and harvest at all levels (Table 1).

Lodging of crops containing vetch was significant at later harvests though the degree of lodging varied. Because forage below the 5 cm cutting height was not harvested the yields in this experiment would have more closely reflected yields achieved when mowing for hay or silage rather than the amount of forage grown. The lower yields on cereal/vetch crops are therefore at least partly due to this lodging rather than differences in productivity between the two components. The biggest effect was on the Gairdner/vetch plots where yield actually declined between the milk and dough stage harvests. The wheat and triticale crops, which were later maturing and therefore harvested later, actually lodged to such an extent that the final harvests of these crops had to be abandoned.

Figure 3. Effect of cereal maturity at harvest on the yield of the cereal and vetch components of cereal/vetch crops grown at Temora, NSW in 2010 at different harvests.

Yiel

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Table 1. Effect of cereal variety, vetch inclusion and harvest on total yield (t DM/ha) of cereal/vetch crops grown at Temora, NSW in 2010.

Cereal species

Cereal variety

Vetch treatment

HarvestBoot Anthesis Milk Dough

Oats Echidna cereal/vetch 17.22 22.97 28.92 29.57cereal only 17.57 28.02 25.94 27.28

Mannus cereal/vetch 15.04 25.79 17.81 23.21cereal only 20.62 19.70 21.57 28.27

Barley Urambie cereal/vetch 10.20 12.27 19.58 17.31cereal only 10.13 16.32 20.10 25.84

Gairdner cereal/vetch 14.86 14.17 25.07 14.47cereal only 19.41 16.37 18.09 31.48

Wheat Wedgetail cereal/vetch 14.47 16.58 14.04 *cereal only 13.60 21.10 24.85 28.74

Strzelecki cereal/vetch 16.13 16.20 14.65 *cereal only 15.12 15.43 22.04 27.95

Triticale Tobruk cereal/vetch 16.56 17.58 17.11 *cereal only 15.97 21.40 30.72 37.719

l.s.d. P = 0.05, 5.82; *Only the plot in replicate one was harvested.


In the mixture, vetch yield increased with harvest, but not cereal variety whereas cereal yield varied (P <0.001) with cereal variety, but not harvest. Cereal and vetch yield for the mixtures at all harvests are presented in Figure 3.

Metabolisable energy contentThe ME content of the crops harvested at Culcairn in 2009 was high (average 10.45 MJ/kg DM) and at the boot stage all combinations except Strzelecki/vetch exceeded ME 10.5 with four crops exceeding ME 11. There were ME differences (P <0.001) among cereal varieties and ME declined (P <0.001) with maturity, though it still remained high. There was no difference in ME between cereal and cereal vetch crops. Average ME was 10.5, 10.5, 10.8, 10.7, 10.5, 10.3 and 10.0 for plots containing Echidna, Mannus, Urambie, Gairdner, Wedgetail, Strzelecki, Tobruk, respectively and 10.9, 10.4, 10.3 and 10.4 for harvests 1, 2, 3 and 4, respectively. All interactions were significant; variety and vetch (P <0.0018), variety and harvest (P <0.001, l.s.d. = 0.283), vetch and harvest (P <0.001, l.s.d. = 0.152) and variety, vetch and harvest (P <0.001).

Average ME content (9.41) of crops at Temora in 2010 was lower than that observed in 2009, varied with cereal variety (P <0.001), declined with harvest and was lower for cereal only

plots. In this experiment, average ME was 9.15, 9.39, 9.89, 9.64, 9.11, 9.41 and 9.38 for plots containing Echidna, Mannus, Urambie, Gairdner, Wedgetail, Strzelecki and Tobruk, respectively and 10.0, 9.52, 9.31 and 8.69 for harvests 1, 2, 3 and 4, respectively As in 2009 there was an interaction between variety and vetch (P <0.001), variety and harvest (P = 0.005), vetch and harvest (P = 0.002) and variety, vetch and harvest (P = 0.024). Predicted means from 2009 and 2010 for all treatments at all harvests are presented in Table 2.

Crude protein contentAverage CP content of the 2009 crops was 12.0%. Crude protein declined (P <0.001) with maturity, varied (P <0.001) with cereal variety and was higher (P <0.001) for cereal/vetch compared with cereal only crops. Average CP was 14.30, 11.84, 10.88 and 9.86% for harvests 1, 2, 3 and 4 and 10.31, 11.37, 12.98, 12.44, 11.09, 12.90 and 12.97% for the Echidna, Mannus, Urambie, Gairdner, Wedgetail, Strzelecki and Tobruk treatments, respectively. Including vetch increased average CP from 6.26 to 17.70%. In 2010, the average CP of the Temora crops was higher at 14.76% and, as was the case in 2009 declined (P <0.001) with maturity, varied (P <0.001) with cereal variety and was higher

Table 2. Effect of cereal variety, vetch inclusion and harvest on metabolisable energy content (MJ/kg DM) of cereal/vetch crops grown at Culcairn, NSW in 2009 and Temora, NSW in 2010.

Cereal species

Cereal variety

Vetch Harvest stageCulcairn 2009 Temora 2010

Boot Anthesis Milk Dough Boot Anthesis Milk DoughOats Echidna vetch + 10.5 10.4 10.3 10.2 10.0 9.6 9.6 8.8

vetch – 11.0 10.7 10.6 10.3 9.3 9.0 8.9 8.0Mannus vetch + 11.4 10.4 10.3 10.1 10.6 9.8 9.6 9.1

vetch – 11.5 9.8 9.7 10.3 10.4 9.3 8.8 7.5Barley Urambie vetch + 10.6 10.6 10.5 10.7 10.3 10.2 10.1 9.7

vetch – 11.1 10.8 10.8 11.1 10.4 9.8 9.5 9.3Gairdner vetch + 10.5 10.6 10.5 10.7 10.5 10.2 10.3 9.6

vetch – 11.1 10.5 10.4 11.3 9.7 9.1 8.8 8.3Wheat Wedgetail vetch + 10.7 10.8 10.0 – 9.9 9.8 9.1 –

vetch – 10.9 10.8 10.4 10.1 9.4 8.5 8.7 8.3Strzelecki vetch + 10.5 10.4 10.7 10.4 * 10.4 10.0 10.2 –

vetch – 10.9 10.3 9.5 10.3 9.3 9.0 8.5 8.4Triticale Tobruk vetch + 10.6 10.5 10.6 – 10.5 10.3 9.7 –

vetch – 10.5 9.4 9.3 9.1 9.6 8.3 8.9 8.4l.s.d. P = 0.05, 0.39 (2009); l.s.d. P = 0.05, 0.54 (2010). *Only the plot in replicate one was harvested.


Figure 4. Effect of cereal maturity at harvest on the crude protein (%) content of cereal and cereal/vetch crops grown at Culcairn, NSW in 2009. Note: only one Strzelecki/vetch plot and no Wedgetail/vetch and Strzelecki/vetch plots were harvested at the dough stage.

Figure 5. Effect of cereal maturity at harvest on the crude protein (%) content of cereal and cereal/vetch crops grown at Temora, NSW in 2010.

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(P <0.001) for cereal/vetch compared to cereal only crops. For the 2010 crops, average CP was 18.08, 16.39, 13.91 and 10.10% for harvests 1, 2, 3 and 4 and 12.44, 13.77, 16.23, 18.36, 14.66, 12.52 and 13.82% for the Echidna, Mannus, Urambie, Gairdner, Wedgetail, Strzelecki and Tobruk treatments, respectively. The effect of including vetch on CP content of cereal and cereal/vetch crops is shown in Figure 4 (2009) and 5 (2010).

Predicted livestock productionPredicted liveweight gain (or loss) for both species was demonstrably lower on the cereal only crops compared to the cereal/vetch crops (Figure 6). The ME content of the cereal only and cereal/vetch crops in 2009 and the earlier harvests in 2010 was adequate to meet requirements for animal growth, however without vetch the CP content of the cereal only crops was inadequate for young, growing livestock. Steers on later harvest cereal only crops, in both 2009 and

2010, were predicted to lose weight because of this. Even the lowest ME content cereal crop, Mannus at the dough stage in 2010 (ME 7.5), should have been adequate for maintenance, but steers were predicted to lose 0.17 kg/day because of the low CP. The lowest predicted production from wethers was maintenance.

Based on predicted liveweight gain, intake and assuming a livestock price of $2.15/kg for steers and $2.60/kg liveweight for wethers estimated value of livestock income from utilising these crops is shown in Figure 7. In both 2009 and 2010, the predicted value of additional livestock production/ha was greater for wethers compared with steers. The predicted returns were higher in 2010 compared with 2009 which was a reflection of significantly higher yields. Where there were only minor increases in yield with maturity, as in 2009, animal production/ha and the value of product/ha was dictated by changes in forage quality. In 2010, animal production/ha varied with individual crops and was dependent on


Figure 6. Effect of cereal variety, vetch and harvest on predicted daily liveweight change of a 300kg 12 month old crossbred British breed steers and 30 crossbred wethers when cereal and cereal/vetch crops grown at Culcairn, NSW in 2009 and Temora, NSW in 2010 are fed to 300kg, 12 month old crossbred British breed steers (kg/day) and 30kg crossbred wethers. Note: in 2009 only one plot of Strzelecki/vetch and none of the Wedgetail/vetch and Tobruk/vetch plots and in 2010 none of the Strzelecki/vetch, Wedgetail/vetch and Tobruk/vetch plots were harvested at the dough stage harvest.

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changes in both yield and quality over time. It should be noted that these predictions do not include any costs of conserving and feeding the forages.

ConclusionsThe yields obtained during dry conditions experienced in 2009 were below normal expectations but much higher than on adjoining pastures (Hackney, personal communication) confirming that cereal and cereal/vetch crops are able to produce good yields even under adverse growing conditions. In 2010, these crops showed their potential to produce very high yields under favourable conditions. Inclusion of vetch did not reduce harvested yield compared with cereal crops in 2009 whereas in 2010 the cereal only crops out yielded cereal/vetch crops

by more than 4 t DM/ha. Lodging of crops containing vetch was a problem in 2010 and reduced harvested yield.

The ME content of the 2009 cereal and cereal/vetch crops was high, generally in the range of 10−11 and remained high for most varieties even as the plants matured confirming the anecdotal belief that drought stressed cereal crops are of higher quality than unstressed crops.

In both experiments, the CP content of the cereal only crops was lower than the cereal/vetch crops and in 2009 at the lower end of the normal range observed in cereals. Inclusion of vetch significantly increased CP compared with cereal only crops in both experiments which was clearly reflected in predicted liveweight gain (or loss) of steers and wethers.


Figure 7. Effect of cereal variety, vetch and harvest on estimated value of livestock production ($/ha) when cereal and cereal/vetch crops grown at Culcairn, NSW in 2009 and Temora, NSW in 2010 are conserved as hay or silage and fed to 300kg, 12 month old crossbred British breed steers (kg/day) and 30kg crossbred wethers. Note: negative values of livestock production from weight loss ignored in these graphs.

2009 Steers

2009 Wethers

2010 Steers

2010 Wethers

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Potential livestock production/ha is dependent on yield, energy and protein content of the crops. Assuming that protein in non-limiting then increasing ME by 0.5 MJ kg/DM over the range 9.5−11.0 ME will increase steer and wether liveweight gain by 310 g and 39 g/day, respectively for the class of livestock used as the example in this paper. Increasing yield and ME while ensuring adequate CP content is the key to increasing livestock productivity and production/ha.

The results from these experiments showed that cereal-based forage crops are a viable option for producers wanting to conserve forage for their

livestock enterprises. However further research is required to identify best management packages for cereal/vetch crops for hay and silage production. This research needs to include selection of species and varieties, ideal sowing rates, optimum sowing times. This research needs to account for regional/district differences and the impact of seasonal conditions.

AcknowledgmentsThe authors wish to acknowledge the support provided by the Australian Centre for International Agricultural Institute for these experiments.


Optimising the intake of feed by pasture-fed sheep and cattle C.T. Westwood

PGG Wrightson, Christchurch, New Zealand, 8042; [email protected]

Abstract: Intake of pasture dry matter (DM) by ruminant species is a critical driver of production and profit for any Australian pasture-based business. Pasture allowance (kg of DM/head/day) is positively associated with intake of pasture DM however excessive allowances may reduce utilisation and quality of pasture grown. Pasture DM intake (DMI) is a function of time spent grazing x bite size x bite rate. Bite size is a key driver of intake, as influenced by depth of bite into a sward and by density of pasture. Grazing time reflects management factors that influence time spent at pasture and whilst is of lesser importance for more extensively managed sheep and beef enterprises, is becoming increasingly important for some large dairy herds. Debilitating animal health conditions and/or management practices that suppress appetite will further reduce grazing time. The presentation of appropriate quantities of high quality pasture to animals and the freedom of pastures from anti-nutritional compounds or contaminants that cause a behavioural aversion to the intake of pasture will improve both intake of pasture DM and utilisation of pasture. The supplementation of pasture-fed sheep and cattle with grains or forages will reduce pasture DMI through substitution, as will restriction of intake of drinking water for some classes of grazing ruminants. Developing a strategy for improved intake of pasture DM requires an understanding of the entire farm system, including the animals and pastures that they graze, stock water access and the concurrent use of supplementary feeds.

Key words: intake, pasture, stocking rate, dry matter, sheep, cattle

IntroductionThe use of grazing sheep and cattle to harvest pasture in situ remains the cornerstone of the relatively simple, low-cost grazing systems of New South Wales (NSW). The diversity of pasture type reflects multiple ecosystems characterised by wide ranging climatic, geographic and topographical parameters. Areas of native and naturalised pastures constrain animal performance (except during drought) as a result of sub-optimal dry matter (DM) yield and quality of pasture. Use of introduced temperate and/or tropical grasses and legumes will potentially enhance animal performance, however efficiencies of use are dictated by rainfall, temperature, elevation, soil types, pests/diseases present and stock classes.

The following key performance indices (KPI) drive the success of pasture-based livestock enterprises:

• Maximumtonnageofpasturegrown(kgDM/ha/year) as influenced by pasture species, soil fertility, pH and drainage, topography, rainfall/irrigation and climate.

• Optimumpasture consumedby livestockgrazed in situ and/or taken as silage or hay (kg DM/ ha/year), expressed as a percentage of pasture grown. Utilisation is influenced primarily by stocking rate (DSE or dry sheep equivalent) per ha.

• Effectiveconversionofpastureconsumedtoanimal products (liveweight, wool or milk).

Our aim is to balance the effective utilisation of pasture grown with the appropriate delivery of nutrients to an increasingly discerning high performance animal. Exceptional pasture utilisation is achieved by matching livestock demand for pasture with available pasture grown – a challenge given between and within season variability in pasture growth rates and pasture quality.

The inverse association between animal productivity and pasture utilisation can challenge the best pasture manager to strike an appropriate


balance between the two KPIs for a business. Inevitably a compromise is reached, with the nutritional demands of pasture-fed, high genetic merit stock not always fully addressed in order to support optimal utilisation of pasture.

Whilst stocking rate remains a key driver of dry matter intake (DMI), further moderators of pasture intake include the health and well being of the animal, grazing management decisions and characteristics of different pasture species.

This paper reviews concepts and ideals for pasture-fed animals with a specific focus on key drivers of DMI. Practical suggestions and ideas for improving the pasture intake of sheep and cattle are discussed.

Drivers of pasture dry matter intake: the animal-pasture interface The successful conversion of pasture to meat, wool or milk begins with presenting to animals high quality, easy to harvest pasture. High quality pasture does not however always guarantee exceptional levels of animal performance. Multiple interrelating animal-centric factors

interact with pasture attributes to collectively determine pasture DMI (Figure 1).

No single pasture, animal or management attribute should be considered in isolation as a potential driver of DMI. Rather each component of the grazing system should be collectively considered, given the multiple interactions between each of these variables.

Dry matter intake (kg DM/head/day) is typically expressed as a function of:

DMI = R x S x T

Where R = bites/unit time, typically minutes; S = average bite size, typically g DM/bite; T = time available for grazing (minutes/day)

Bites per unit timeThe number of bites taken per minute is influenced by both animal and pasture associated factors. Sheep and cattle differ in their time efficiency of pasture harvest. Cattle are more efficient harvesters of pasture because they chew feed less thoroughly before swallowing. Sheep spend more than double the amount of time chewing prehended feed before swallowing –

Figure 1. Factors that influence the intake of pasture dry matter by sheep and cattle.


contributing to a relatively slower, less efficient rate of feed consumption. Cattle swallow feed quickly and move on for another bite of pasture, whilst sheep continue to chew and swallow before moving onto their next bite.

An animal’s ability to take multiple bites per minute is influenced by the time taken to open the mouth, to tear or bite pasture and to close the mouth. Slower bite rates can occur with higher pasture masses because a greater mass of feed requires more chewing, potentially slowing the rate of bites per unit time. Conversely, sheep (but not cattle) grazing shorter pasture swards can increase daily bite rates as a compensatory means for smaller bite sizes. More bites per day often does not compensate for a smaller bite mass, therefore daily DMI typically falls on short pasture swards.

Dairy cows of high genetic merit have faster biting rates and longer grazing times compared with cows of low genetic merit (Bargo et al. 2003) implying potential milk yield and/or body condition benefits for dairy cattle. Potential DMI advantages do not necessarily translate to improved body condition score if greater DMI fails to adequately compensate for the greater genetic drive to produce milk and/or pasture is not offered to cattle in an easy to harvest state.

Leafy, upright, dense, highly digestible pasture can be quickly and effectively harvested within a fixed number of bites per day. High quality pasture is unlikely to directly restrict intake of pasture DM unless pasture allowances are inappropriately low.

Conversely, as pasture grasses mature, flower and reproduce, or lose quality for other reasons including severe frosting and/or leaf loss through senescence, tensile strength and shear time increase, slowing the rate of harvest and decreasing the number of bites per unit time. For intensively managed pasture systems, pre-grazing topping/slashing, a shorter rotation length, strategic nitrogen (N) fertiliser use or removal of poorer quality pasture as silage or hay are all advocated as ways to aid overall pasture DM intake by stock.

Sheep will slow their consumption of pasture when the sward contains predominantly dead material with only a small pick of green leaf, due to the time consuming process of active selection (Forbes 2007a).

Surface moisture on external leaf surfaces can change the coefficient of friction, slowing the bite rate by cattle because of slippage of pasture between the incisors and dental pad, contributing to slower swallowing times. This has implications for high performance stock classes such as dairy cattle grazing in wet weather, or following a heavy dew.

Increasing the legume and/or herb component of a mixed pasture sward is a common strategy used to minimise the impact of poor quality grasses on reduced bite rate (and bite size). Grasses with different heading dates, with reduced aftermath heading and tetraploid ryegrasses used in place of diploid cultivars are options to consider when selecting grasses for more intensively managed systems.

Average bite sizeBite size is a function of both animal and pasture characteristics. Cattle will consume more DM per bite than sheep when offered pasture of similar pregrazing mass and height, due to cattle consuming a larger mass of feed per bite. Bite size (200−1100 mg DM/bite for cattle and 83−93 mg DM/bite for sheep) is a key driver of pasture DMI. Animal liveweight does not influence bite rate, but can influence bite size because heavier, larger dairy cattle consumed larger bites than smaller, lighter cattle (Laborde et al. 1998).

Physiological state influences bite size because lactating ewes consumed more feed per bite than dry sheep and fasted sheep ate more per bite than non-fasted sheep (Cosgrove and Edwards 2007).

Pasture length (height) and pasture density are important moderators of pasture DM consumed per bite (Figure 2). For temperate pastures, pasture height is the major limiter of bite size, as influenced by bite depth in the sward rather than bite area (Cosgrove and Edwards 2007). Around one third of the height of pasture is removed


by a grazing dairy cow (Bargo et al. 2003) and between 30 and 50% by beef cattle and sheep, irrespective of pasture height. Reduction of pasture height to inappropriately low levels is an important constraint to DMI by all classes of ruminants, particularly cattle.

The relationship between pasture height and bite size varies with pasture type (temperate vs tropical, vegetative vs reproductive grass states) and between set stocking and rotationally grazed swards. Care is required when recommending sward heights that optimise DMI. For example, for tropical pasture species, the proportion of green leaf mass: stem present is a more appropriate predictor of probable bite mass than pasture height alone.

Pasture plant and leaf density will influence final bite size as well as bite rate. Bulk density of pasture within the bite catchment is a more important determinant of bite size than plant erectness per se (Elliot and Hughes 1991). If density of pasture is low, stock will take more steps between bites and each bite collected may contain less material, limiting total DM intake.

For temperate, ryegrass dominant pastures, optimum pasture heights that encourage the best amount of DM consumed per bite are: • Setstockedewes:>4−6cm• Setstockedbeefcattleanddeer:>8−10cm• Dairycattle:>18cmheight

Tall swards do not guarantee more DM per bite because if bulk density of pasture decreases and

stalky poor quality pasture is present, stock may consume less feed per bite than a shorter, denser sward. More DM per bite from a taller sward doesn’t always translate to a greater intake of DM because as bite mass increases, prehension biting rate can decrease (Cosgrove and Edwards 2007; Figure 3) due to increased chewing time required for a bigger mouthful of feed.

Short pasture may constrain bite size, because there is less feed available per bite. At shorter pasture heights, both grazing time and biting rate can to some degree compensate for a reduced bite mass (g of DM per bite) harvested per bite however it is generally accepted that cattle (unlike sheep), have limited scope to alter bite rate adequately to compensate for reduced bite size.

Pasture species will modify feed consumed per bite because for sheep, bite masses were greater from white clover swards than from perennial ryegrass swards (Cosgrove and Edwards 2007), reflecting a greater bite area and reduced chewing time associated with the consumption of white clovers.

Time available for grazing/motivation of the animal to consume pastureTime spent grazing is function of:• Timemadeavailableforstocktograze• Thewillingnessoftheanimaltoeffectively

utilise available time grazing.

Kg D

M /

day

2

3

3 6 9 12

Sward Height (cm)

0

0

1

Figure 2. Relationship between sward height and intake of dry matter by sheep grazing temperate pastures (Cosgrove and Edwards 2007).

Figure 3. Relationship between sward height and bite rate by sheep grazing temperate pastures (Cosgrove and Edwards, 2007). As sward height increases, fewer bites are needed to prehend feed, but more chews are required per bite to process feed before swallowing.


Time on pastureFor drystock sheep and beef enterprises, time available for grazing is not a common moderator of the R x S x T relationship with stock that are typically continuously at pasture. Inclement weather (heat, rainfall, wind chill) and stock movement towards watering points in extensively managed, larger paddocks will modify grazing time, as will prolonged time off pasture during yarding. Stock can however compensate for time spent away from pasture by increasing grazing time and eating more quickly after returning to pasture (Cosgrove and Edwards 2007).

For dairy cattle, grazing time is considered an important modifier of DMI, particularly for larger dairy cattle herds. With the size of the average Australian herd increasing over recent years, grazing time is becoming a more commonly encountered limiter of pasture DMI. Within larger herds, the effect of daily activities including walking and milking on time available for grazing is greater than for smaller herds. Dairy cattle are unwilling or unable to graze for more than 10−12 hours/day and may have a maximum grazing duration of just over 13 hours/day (Bargo et al. 2003). Within a 24-hour day in addition to grazing, cows have a fixed time requirement for ruminating and sleeping. Cattle are unlikely to adequately compensate for restricted grazing time by increasing either bite rate or bite size, therefore net daily pasture DM falls.

Inclement weatherExtremes of temperature outside of the thermoneutral zone (5 to 20°C for cattle; –5 to 35°C, fleece dependent for sheep) will influence the DMI and metabolic activity of pasture-fed sheep and cattle (NRC 2001).

Adverse winter weather events reduce DMI because stock seek shelter in preference to grazing, reducing the daily grazing times, despite increased basal metabolic intensity and an increased drive to consume feed. Wet, muddy conditions reduce pasture utilisation, accentuating the challenge of poor pasture DMI. Selecting free draining paddocks, offering shelter to reduce wind chill, and offering rotationally grazed, break fed animals a larger than normal

area of pasture are the standard approaches to managing for very cold, wet conditions.

Conversely, during extreme heat and humidity, stock seek shade in preference to grazing, reducing daily DMI. Acute heat exposure will reduce DMI by pasture-fed stock to a greater extent than chronic exposure to heat because stock are capable of some acclimatisation to heat, however the response to heat is both species and breed dependent. Grazing cattle are on average less tolerant of heat than sheep however heat tolerance is moderated by fleece length, age and physiological state. Under hot grazing conditions, middle eastern sheep breeds including the Awassi will maintain a greater appetite for pasture than Merinos which in turn tolerate heat better than British breeds.

Pasture-fed beef cattle are more tolerant of heat than dairy cattle because heat production by beef cattle is generally less than that of lactating dairy cattle. Under hot conditions, Bos taurus breeds cease grazing and seek shelter earlier in the day than B. indicus breeds, and crossbreds consumed more total DM than either B. taurus or B. indicus (Forbes 2007b) illustrating the potential benefits of hybrid vigour with regard to heat tolerance at pasture.

For grazing stock, the effects of heat stress are accentuated by concurrent changes in pasture quality. Hot conditions predispose to greater concentrations of cell wall constituents for both temperate (C3) and tropical (C4) species. More cellulose, hemicelluloses and lignin increases the heat of fermentation generated during digestion, accentuating the effects of environmental heat stress and reducing voluntary intake of pasture. Strategies that target improved forage quality through management and/or forage selection will potentially reduce the ruminal heat of fermentation.

Ergovaline or ergopeptides produced by perennial ryegrass and tall fescue infected by wild type endophytes, respectively may accentuate the effects of heat stress. Modern cultivars contain endophytes that produce lowered or nil concentrations of ergopeptide alkaloids, offering alternative pastures that reduce risk of heat stress.


During hot weather, offering intensively managed stock relatively greater areas of pasture at night will encourage improved pasture consumption and utilisation. Increased grazing activity can be encouraged by establishing shade areas and salt block locations away from watering points, encouraging stock to graze as they move between shade, salt licks and water during hot weather. Further practical tips regarding the management of pasture-fed dairy cattle through the hotter months are well reported and summarised by www.coolcows.com.au.

Motivation by the animal to graze Desire to graze is moderated by health and well being, pasture allowance, pasture quality and the freedom of pasture-associated anti-nutritional compounds that restrict the consumption of DM. Factors include:

Physiological state of the animal and the desire to consume pasture. Demand for nutrients is defined by the requirement for energy, protein, macro and trace minerals, as influenced by liveweight (and hence maintenance demands), liveweight gain, pregnancy and/or lactation, and walking during grazing or whilst accessing stock water. Energy and protein demands can be calculated by feed formulation programs, or can be manually calculated in a factorial manner. Sheep and cattle with a greater demand for energy and other nutrients will tend to have a greater ‘drive’ for DMI to support those needs.

Physical satiety or factors associated with the distension of the alimentary tract. For stock maintained on high quality, highly digestible temperate pastures, ruminal distension is an uncommon constraint of DMI. Conversely, for laxly grazed, poor quality pasture e.g. when grasses are heading in late spring, ruminal distension may constrain pasture intakes. Ruminal capacity (or ‘stretch’) will allow stock to adapt to some degree to high fibre diets, however despite capacity adaptation, high fibre diets remain unsuitable for high performance stock classes including lactating dairy cattle.

Health constraints to DMI.Appetite suppression secondary to illness or injury will limit an animal’s ability to effectively graze. Anorexia as a

result of hyperthermia (high body temperature) associated with infectious disease, or anorexia secondary to ruminal acidosis, metabolic disease e.g. sleepy sickness pre-lambing or lameness due to e.g. footrot, can reduce the desire to graze.

The sudden transition of stock from poor to high quality pasture may constrain DMI, particularly in cattle. Reduced appetite may reflect sub-clinical or clinical ruminal acidosis. Alternately a learned aversion to high quality pasture may reflect high concentrations of ruminal and blood ammonia that can accompany the abrupt transition from poor to good quality pastures.

Clinical and sub-clinical ruminal bloat will restrict pasture DMI because ruminal distension, frothy or free gas (‘feedlot’) bloat limits ruminal capacity and the desire to eat.

Temporal grazing patterns and grazing time. Diurnal variation in grazing behaviour modifies both the duration and pattern of grazing activity. Under temperate conditions, most grazing occurs during daylight hours, with the greatest activity during the early morning and late afternoon. During late afternoon grazing, sheep have greater bite masses which combined with greater grazing activity lifts the rate of intake late in the day. For dairy cows, pasture DMI is often greatest in late afternoon/pre-dusk resulting from a combination of increased grazing activity and the greater DM % of pasture at dusk. The nutritional status of stock can be improved by late afternoon grazing because concentrations of water soluble carbohydrates (WSC) in grasses and starches in legumes are typically greatest pre-dusk. Animal species and physiological state moderate grazing patterns because for lactating dairy cows, the greater metabolic ‘drive’ to eat encourages the active consumption of pasture at night in addition to during the day (Cosgrove et al. 2006; Cosgrove and Edwards 2007).

Pasture species further moderate temporal grazing patterns because dairy cows grazing side by side monocultures of ryegrass and clover spent proportionately more time grazing at night than cows grazing either grass only, a grass/clover pasture mix, or grass at night and clover during the day (Cosgrove et al. 2006).


Climatic conditions moderate grazing behaviour because hotter conditions are associated with reduced daytime grazing activity, typically compensated for by greater time grazing during the night.

The exact control mechanisms that initiate and terminate a grazed pasture ‘meal’ remain unknown and most likely reflect multiple factors including concentrations of volatile fatty acids, ammonia and ruminal pH. Taweel (2004) concluded that termination of grazing by dairy cows at dusk was triggered by factors associated with ruminal distension.

Psychogenic effects on grazing time and pasture DMI. The psychogenic regulation of DMI involves the animals behavioural response to inhibitory or stimulatory factors associated with the pasture and/or paddock.

Grazing management techniques can modify behavioural response by stock to pasture and therefore potential DMI. For example, use of electric fencing to break feed pasture may reduce grazing time (and hence intake of pasture) because stock cease grazing despite relatively high post-grazing residuals, in anticipation of being moved onto a new break of pasture.

Palatability of pasture plants also modifies psychogenic regulation of pasture DMI. Stock often express preference for one type of pasture species over another. The rejection or acceptance of less palatable species is a function of soil type, fertiliser use, incidence of plant disease, companion pasture plants present, grazing management and pasture allocation. Less well accepted pasture species are more likely to be consumed when animals are underfed. Table 1 outlines examples of paddock-centric factors that may influence the intake of pasture DM.

Pasture composition and DMI by sheep and cattle The extremely variable composition of pasture, expressed both as the proportional contribution of various pasture species and cultivars, and as the overall nutritional composition of the sward [DM%, neutral detergent fibre (NDF) and

crude protein (CP)] will directly and indirectly influence DMI by grazing ruminants.

The influence of grass, legume and herb species In sheep, a higher forage DMI is associated with forages characterised by low NDF concentrations with fewer widely spaced and fragile veins (Waghorn and Clark 2004) because less physical damage by chewing is required to reduce particle size of the forage; this relationship will likely be true for beef and dairy cattle also. High quality legumes are desirable components of a pasture sward because legumes contain, on average, greater concentrations of desirable nutrients per kg of DM and have been associated with greater DMI by cattle compared with intakes reported for grass-fed cows. The preferential grazing by cattle of pasture herbs chicory (Cichorium intybus) and plantain (Plantago lanceolata) established as part of perennial ryegrass/white clover swards is widely reported and is likely associated with a greater total intake of pasture DM.

Digestibility, metabolisable energy content of pasture and DMIA positive association between pasture digestibility and pasture DMI is generally presumed (Waghorn and Clark 2004). Paradoxically, as pasture DMI increases, the digestibility and megajoules of metabolisable energy content of pasture declines, a function of more rapid rumen outflow rate and reduced extent of digestion of pasture DM. Management practices that encourage higher quality, more digestible pasture swards remain the aim for any high performance pasture system.

Neutral detergent fibre content of pasture and pasture DMI For Total Mixed Ration (TMR)-fed ruminants, the quadratic correlation between ration NDF content and the potential DMI of animals is well reported. High concentrations of forage NDF can limit DMI, however the rate and extent of NDF degradation will moderate this relationship. Conversely, low NDF concentrations constrain


energy intake because feedback inhibitors (satiety) limit DMI (Figure 4).

For grazing ruminants, the relationships between forage NDF, rumen fill and pasture DMI are less well understood (Waghorn and Clark 2004), because ruminants can to some extent adapt to the chronic ingestion of high NDF pasture. The rumen contents of pasture-fed New Zealand dairy cows at 70 days after calving was 22% of liveweight compared with 17 and 12% of liveweight for cows in the USA fed pasture or TMR diets, respectively (Waghorn and Clark 2004) suggesting a long-term adaptation by New Zealand cattle to the ingestion of relatively high NDF pastures.

The concentration of dietary NDF is often used as a ‘rule of thumb’ to predict the potential DMI of cattle and sheep. For TMR fed stock, an upper limit of no more than 1.2% of liveweight as NDF appears to approximately correlate with intake of DMI. This TMR NDF rule-of-thumb is unlikely to apply to stock that consume temperate high quality species because of the relatively greater rate and extent of ruminal degradation of

Table 1. Factors that may contribute to the psychogenic regulation of pasture dry matter intake.

Pasture-centric factors that may adversely influence intake of pasture by grazing cattle

Prostrate pasture species (e.g. grazing brome Bromus stamineus) compared with those with a more upright, erect growth habit (e.g. Italian ryegrass Lolium multiflorum).

Diploid ryegrasses with thinner, less erect tillers consumed less vigorously compared with more upright tetraploid ryegrasses characterised by fleshier tillers and larger leaves.

Perennial ryegrass cultivars that contain the wild type endophyte, producing endophyte alkaloid compounds characterised by reduced consumption of pasture. Newer novel endophyte−ryegrass associations e.g. AR1 or AR37 are generally associated with improved pasture DMI compared with ryegrasses infected with a wild type endophyte.

High pasture contents of sulfur, potassium, and possibly nitrates.

Lower pasture contents of WSC due to recent application of nitrogen fertiliser or cultivar effects (differences in WSC concentrations have been reported between ryegrass cultivars and between tall fescue cultivars).

Presence of disease such as leaf rust or leaf spot on pasture surface or fungi at the base of sward e.g. Fusarium.

Overzealous use of supplementary minerals, e.g. heavy application of fine lime to pasture as a calcium supplement.

Recent application of effluent to pasture or areas of pasture heavily soiled by faeces, cattle appear more adverse to the presence of faeces than sheep to faecal-soiled pasture. Pastures covered with dust or mud may reduce pasture harvesting rates.

Previous grazing in recent days of pasture break with another stock class e.g. calves and associated faecal/urine staining of pasture.

No stock water access in the paddock (importance of this point depends on the DM% and hence water content of the grazed pasture).

Learned response by stock to daily routine of shifting cattle onto a new break of pasture, inhibiting grazing activity on existing break whilst waiting to move onto new break.

pasture NDF compared with hay and silages (Kolver 1998).

The practical use of NDF as a rule-of-thumb predictor of intake of pasture DM is either inappropriate, or requires the use of alternate coefficient. For dairy cows consuming high quality pasture, an upper limit of 1.5% of bodyweight as NDF may be more appropriate (Kolver and Muller 1998).

Figure 4. Illustration of intake predicted by simple concepts of energy demand (Ie) and fill limitation (If) when compared with intakes typically observed when ration NDF is varied (Mertens 2009).


Dry matter content of pastureThe DMI of TMR-fed stock is said to be optimised by a target ration DM% of between 40 and 60% DM. With high quality, immature leafy pastures characterised by DM concentrations as low as 11% of wet weight (Stevenson et al. 2003) the intake of a high volume of water relative to DM has been proposed as a potential modifier of DMI by stock, particularly when surface water is also present as a result of rainfall, dew or irrigation.

Mechanisms that limit the voluntary consumption of low DM%, wet pastures are unclear but may include a reduced efficiency of harvest of low DM% pasture. For a high performance dairy cow to collect 20 kg DM as wet grass would necessitate a wet volume intake of 200 kg of 10% DM pasture. For a confined cow fed a TMR formulated at 40% DM, wet intake is only 50 kg to provide 20 kg DM, requiring relatively fewer mouthfuls, with less physical exertion and less motivation required. An inefficiency of harvest of low DM% pasture will be less relevant for dry stock that are continuously at pasture.

Ruminal distension caused by excessive intake of water when low DM% pasture is consumed is an unlikely contributor to DMI restriction. The placement of a balloon containing water in the rumen of young growing lambs limited the DMI of dried but not fresh (DM 15−25%) forages (John and Ulyatt 1987). Damage to plant cells during prehension and chewing causes virtually complete release of intracellular water and soluble nutrients, allowing the ready absorption of water.

Fat content of pasture and pasture dry matter intakeAn inverse association between the fat concentration of a ration and DMI reflects the effects of both increased energy density of high fat diets impacting on energy satiety and therefore appetite, as well as reduced digestibility of fibre in the presence of higher concentrations of dietary fat. Fat concentrations of high quality leafy pasture may exceed 7% of DM and are characterised by a relatively high proportion of polyunsaturated fatty acids (PUFA), frequently

implicated as potent inhibitors of ruminal fibre digestion. Total fat intakes by stock grazing higher quality pastures can exceed the recommended upper concentration of no more than 5% of DM and faeces from these pasture-fed cattle can sometimes appear ‘greasy’ or ‘oily’. The relationship between potentially high PUFA intakes by pasture-fed cattle and pasture DMI requires further elucidation.

Crude protein content of pastureHigh concentrations of pasture crude protein are unlikely to moderate DMI of stock unless very high levels of ruminal or blood ammonia contribute to a learned aversion to pastures following an acute change in diet. Low levels of crude protein may contribute to reduced pasture digestibility through inappropriately low concentrations of both total dietary crude protein and rumen degradable protein required to support optimal rumen microbial function. Stock will to some extent adjust to low concentrations of dietary crude protein through improved efficiencies of nitrogen recycling as salivary urea.

Water soluble carbohydrate content of pasture and DMIThe concentration of WSC varies considerably among pasture species and potentially among cultivars of ryegrass and clover (Edwards et al. 2007), as well as being influenced by temperature, season and use of nitrogenous fertilisers. The positive correlation between WSC content of pasture and grazing preference is reported anecdotally in the field, yet is not strongly supported by investigations of the association between DMI by cattle and concentration of WSC in pasture species under controlled experimental conditions (Taweel 2004; Edwards et al. 2007).

Concentrations of macro minerals Anecdotal reports suggest that under some conditions, high pasture concentrations of potassium and sulfur may negatively influence the consumption of pasture DM.


Anti-nutritional compounds Anti-nutritional compounds associated with pasture including mycotoxins and endophyte a lka loid compounds may reduce the consumption of pasture DM by grazing cattle and sheep. Mycotoxins include those associated with fungal growth in dead litter at the base of the sward including Fusarium spp. The presence of crown or leaf rust (Pucinnia coronate) on the surface of ryegrass plants may reduce the rate and extent of consumption of pastures by grazing cattle. The production of a range of endophyte alkaloids by many ‘wild type’ perennial ryegrass−endophytic fungal associations are negatively associated with the acceptance of pasture by cattle and sheep. Newer perennial ryegrass−novel endophytic associations produce alternate profiles of endophyte alkaloids that are less likely to negatively impact on pasture DMI of cattle and sheep. Pastures with a high content of nitrate N have been associated anecdotally with a higher incidence of pasture refusal by cattle.

Access to stock water and effects on DMIRestricted access to stock water and/or reduced water consumption due to undesirable water attributes will influence DMI. Ruminants respond to reduced consumption of water by reducing meal size, possibly as a protective homeostatic mechanism for maintaining the normal osmotic buffer function of the rumen and therefore regulating osmotic balance of body fluids (Burgos et al. 2001). The DMI of pasture-fed stock may be less influenced by variable water intake than hay or silage-fed stock because of the relatively greater intake of water consumed from pasture. Very lush pasture that contains water at 85% or more of wet weight may reduce or even remove requirements for supplemental stock water for some stock classes under cool conditions.

The influence of water restriction on pasture DMI is variable, being influenced by pasture DM%, mineral concentrations of both pasture and water (sodium, particularly), ambient temperature, species and breed. Sheep on

average consume less water per kg of DM of pasture than cattle.

Water for pasture-fed stock should be of acceptable volume and quality. Undesirable water quality attributes including undesirable taste and odour attributes, dissolved calcium, phosphorus, magnesium and sulfur can affect water intake and therefore, intake of pasture DM. Conversely, excessive intakes of salts, such as sodium chloride, can increase water intake as the animal attempts to eliminate excess sodium with little if any consequence for total daily DMI.

The appropriate location of easily accessible watering points that contain acceptable quality water is an important modifier of potential intake of pasture by stock, particularly under hot environmental conditions.

Conclusions The successful management of the interface between pasture and the grazing animal is a critical driver of profit for NSW pastoral businesses. Whilst achieving the target ‘fine line’ balance of achieving optimum pasture DMI by stock and excellent utilisation of pasture is challenging, achieving this balance is an appropriate and attainable target for most pasture-based businesses.

Pasture allowance remains possibly the most important driver of pasture DMI and is one key aspect of pasture management that can be both monitored and controlled by farm managers. For more intensively managed systems including dairying, grazing time is an important moderator of DMI. Grazing time constraints may be relevant for more extensively managed systems, as influenced by extremes of environmental temperature, adverse weather events and proximity of pastures to stock watering points. Bite size as influenced by pasture allowance and bite rate contribute to net daily pasture DMI, albeit to a lesser extent than grazing time.

Within the agronomic constraints of an individual paddock or property, pasture should ‘ideally’ be presented as a high quality, easy to harvest feed and remain free of associated compounds that might otherwise reduce an


animal’s desire to consume pasture. By allowing stock access to appropriate quantities of high quality temperate pastures for an appropriate length of time, grazed no lower than 4–6 cm (sheep) or 8–10 cm (beef and dry dairy cattle) or 18 cm (lactating dairy cattle) will typically allow stock sufficient bite sizes to support optimal intake of pasture DM, whilst utilising acceptable quantities of pasture grown. Measures of animal productivity including rate of liveweight gain, body condition score and or reproductive indices must be monitored to ensure pasture utilisation is not being achieved at the expense of animal well being and productivity.

Maximising DMI by pasture-fed ruminants requires an understanding of all factors that collectively influence DMI by individual animals, whilst optimising utilisation of pasture grown.

ReferencesBargo F, Muller LD, Kolver ES, Delahoy JE (2003) Invited

review: Production and digestion of supplemented dairy cows on pasture. Journal of Dairy Science 86, 1–42.

Burgos MS, Senn M, Sutter F, Kreuzer F, Langhans W (2001) Effect of water restrictions on feeding and metabolism in dairy cows. American Journal of Physiology, Regulatory, Integrative and Comparative Physiology 280, R418–R427.

Cosgrove GP, Burke JL, Death JF, Lane GA, Fraser K, Pacheco D, Parsons AJ (2006) Clover-rich diets and production, behaviour and nutrient use by cows in late lactation. Proceedings of the New Zealand Society of Animal Production 66, 42–49.

Cosgrove GP, Edwards GR (2007) Control of grazing intake. In ‘Pastures and supplements for grazing animals.’ (Eds. PV Rattray, IM Brookes, AM Nicol). pp. 61–80. Occasional Publication No. 14. (New Zealand Society of Animal Production).

Edwards GR, Parsons AJ, Rasmussen S (2007) High sugar grasses for dairy systems. In ‘Meeting the challenges for pasture-based dairying’. (Eds DF Chapman, DA Clark, KL McMillan, DF Nation). pp. 307–334. In ‘Proceedings of the 3rd Australasian Dairy Science Symposium’, Melbourne, Australia.

Elliot AW, Hughes TP (1991) Short term intake of Friesian heifers grazing three pasture species. Proceedings of the New Zealand Society of Animal Production 51, 465–468.

Forbes JM (2007a) Feeding Behaviour. In ‘Voluntary Food Intake and Diet Selection in Farm Animals’. pp. 12–40. Second edition, (CAB International, Oxfordshire, UK)

Forbes JM (2007b) Environmental Factors Affecting Intake. In ‘Voluntary Food Intake and Diet Selection in Farm Animals’. pp. 365–390. Second edition, (CAB International, Oxfordshire, UK)

John A, Ulyatt MJ (1987) Importance of dry matter content to voluntary intake of fresh grass forages. Proceedings of the New Zealand Society of Animal Production 47, 13–16.

Kolver ES (1998) Digestion of pasture by dairy cows. In ‘Proceedings of the 15th Annual Seminar of the Society of Dairy Cattle Veterinarians of the New Zealand Veterinary Association’. pp. 175–188.

Kolver ES, Muller LD (1998) Performance and nutrient intake of high producing Holstein cows consuming pasture or a total mixed ration. Journal of Dairy Science 81, 1403–1411.

Laborde D, Garcia-Muniz JG, Holmes CW (1998) Herbage intake, grazing behaviour and feed conversion efficiency of lactating Holstein-Friesian dairy cows that differ genetically for liveweight. Proceedings of the New Zealand Society of Animal Production 58, 128–131.

Mertens DR (2009) Maximising forage use by dairy cows. In ‘Proceedings of the Western Canadian Dairy Seminar’. pp. 303–319.

National Research Council (2001) In ‘Nutrient Requirements of Dairy Cattle’. Seventh revised edition. (National Academy Press, Washington DC)

Stevenson MA, Williamson NB, Russell DJ (2003) Nutrient balance in the diet of spring-calving, pasture-fed dairy cows. New Zealand Veterinary Journal 51, 81–88.

Taweel HZ (2004) Perennial ryegrass for dairy cows: grazing behaviour, intake, rumen function and performance, PhD thesis, Wageningen University, The Netherlands.

Waghorn GC, Clark DA (2004) Feeding value of pastures for ruminants. New Zealand Veterinary Journal 52, 320–331.

11 KIRKCALDY STREET

BATHURST


Varying sheep production from different pasture typesJ. Brien

”Ardnai”, Greenethorpe, NSW 2809: [email protected]

Abstract: With high land values, and variable climatic and economic conditions which producers cannot control, there is a need to reduce the exposure of farm businesses to inflating costs and continue to make production gains to offset diminishing returns of trade.

Australia possesses a unique position in the world where we can increase sheep productivity through fertility and finishing animals for market through improved and high quality pastures. While the costs of these improved pastures remains a concern for producers, new varieties and planting methods can be used in an integrated system to reduce the costs of long-term improved pastures and also allow producers to benefit from opportunity cropping programs. These systems are also an efficient tool in reducing the threat of long periods of drought as they are well adapted to dry climates and very effective water users.

Key words: biserrula, serradella, bladder clover, dry matter

Introduction “Ardnai,” “Glenholm” and “Lonepine” make up a mixed farming operation at Greenethorpe, New South Wales (NSW) a small village between Cowra, Young and Grenfell. Our farm is half cropping which is run by my brother David and I run the sheep operation. The farm is 850 ha with half sown to winter crops of wheat, lupins and canola. The other half dedicated to improved pastures, such as lucerne, clover, phalaris, fescue, cocksfoot and chicory. We run the pasture phases from 5 to 10 years, and run a composite ewe flock and a hay and silage contracting business which makes the most of excess feed. Our ewes cut about 4 kg of 32 micron wool and we are trying to maintain 150% adult lambing rate turning-off lambs that average 23 kg dressed weight. Our legume-based pastures produce quality feed as well as add nitrogen (N) for the cropping phase. Resistant ryegrass can be a problem in the cropping phase, but not to composite ewes or to a baler.

New plant varieties and plant selection are not a new concept in farming, in fact it has been practised since the inception of farming. New plant varieties and plant selection these days are big business and each producer needs to evaluate what is the right plant for the specific job in their environment for the most cost effective production response. These selection

tools have been used in stock selection too. With the current Australian sheep flock as low as the early 1900s (Figure 1) much selection has already taken place in the industry. The Australian sheep flock now has far less wethers and a much larger percentage of breeding ewes (Curtis 2009) which means we should now have the means to capitalise on great gains on the remaining gene pools as remaining animals would have been retained on specific merits such as wool cut, micron, growth rate, meat yield and fertility.

Figure 1. Sheep and lamb numbers 1906−2006.

With many matings being based on meat outcomes in the past few years this has only heightened the need to maintain a higher reproductive rate with a lower wool income. Lamb marking percentages have been less than 80% in most states (Fogarty 1984a, b). While in Australian prime lamb operations 1.4 lambs appears to be the maximum per ewe per year and per 0.1 lambs between 1.0 and 1.4 can increase producers profitability by 5−15% (Hall 1984).


http://www.abs.gov.au/ausstats/[email protected]/mf/7124.0


Wean More Lamb workshops held by Meat & Livestock Australia and the Department of Primary Industries (DPI) showed that more profitable producers have higher weaning percentages. Higher weaning percentages mean a larger return on investment for producers, but management must also be tailored to enhance higher fecundity, fertility and lamb survival.

Background Many of our competing countries in the southern hemisphere are severely limited by their climatic conditions and the available pasture to produce stock. South Africa has veld, South America has majinas and desert landscapes. And the United Kingdom (UK) has different levels of nutrition at different levels in the landscapes and must conform to public ideals of production methods, but also maintain park appearances of some types of land with others carefully conserved under traditional farming methods.

While travelling on my Nuffield scholarship I found that there were very few countries that have the conditions we have here in Australia. South America is losing its meat sheep zones to soybean production and Patagonia is struggling to maintain nutrition levels of ewes for high levels of production. Even in the UK highly improved pastures require a lot of fertiliser and maintenance to produce good quality feed and the level of production is determined to land type. The lowlands achieve very high fertility rates in excess of 150% and high meat production where as the hill country struggles to sustain more than 60% fertility in the same animals (B Wolfe, pers. comm.) New Zealand has lost much of its high producing sheep country to dairying which is a constant reminder that per hectare gross margins need to be maintained.

A 10% increase in ovulation rate in New Zealand translates to 6.9% more lambs at lambing and 5.7% more lambs marked. What does this figure now translate to in Australia with a high dollar and high demand? Flushing is also a management tool being promoted to increase higher ovulation rates, but only appears responsive to a certain ewe liveweight and condition score. The EverGraze program recently found that flushing

ewes for a week prior to joining increased ovulation rates in merino ewes at Wagga Wagga, and this is in line with techniques used in New Zealand and the UK. This shows an opportunity to the Australian industry that we can control ovulation rate through our pastures and then increase lamb survival with high quality pastures at low cost effective levels.

Pasture systemImproved pastures and mixed farming in the sheep-wheat belt can better boost fertility along with gross margins by selection pressure on sheep and re-evaluation of pasture/legume systems. For many years, the sheep-wheat belt has operated under the system of long cropping phases (up to 10 years) and a medium- to long-term pasture phase (5−10 years) depending on the region. Much of the cropping zone has approached this pasture phase as a N build up phase with grazing and opportunity hay or silage making. This approach has worked very well for us, but we have to re-evaluate the length and types of pastures we use due to the sowing and seed costs. Perhaps in the future we will also have to consider different pasture types due to the carbon scheme. Serradella has the benefit of no plant oestrogens and therefore there is no infertility with this legume as there are with some others (Craig 2005).

At our property “Glenholm”, DPI have trialled some newer species to our region such as serradella, biserrula and bladder clover looking to reduce sowing costs and give a short-term pasture phase which fixes significant amounts of N and provides cheap good quality feed for livestock.

Recent trials conducted at “Glenholm”, by B Hackney, DPI and her team trialled different types of establishment and measured dry matter (DM) production.

Dry matter production in year two varied with pasture type (Figure 2). Bladder clover being a clear stand out with cover cropping, but most of the pastures had much better DM production that the first sown pasture this year. With twin sowing a very good producer after laying dormant under a full wheat crop the year


before and germinating with good conditions the following year.

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Figure 2. Winter production from regenerating stands. CC, pastures sown with a cover crop; TS, twin sowing − unscarified hardseed is sown with the crop to germinate the following year. Initial sowings were done in 2009. (Source: B Hackney)

Department of Agriculture and Food Western Australia (DAFWA) have conducted trials with biserrula and found it gave them a longer grazing window when compared with normal clovers. Additionally, some of these pastures are even more palatable with senescence and seed is very nutritious and sought after by stock.

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Figure 3. Total dry matter production in 2010. (Source: B. Hackney)

A substantial amount of DM can be produced from these new varieties compared with subterranean clover (Figure 3). The even bigger opportunity is to grow these in rotation with crops to gain the benefit of the N captured by the legumes, to lengthen feed production with other pastures and to reduce the cost of sowing pastures and N fertilisers. While some species may be better sown alone as scarified seed in the first year, once established, producers can crop on the hardseed and allow pasture to regenerate in subsequent years. The number of years that cropping can be supported varies between species and varieties and is related to the hardseed content of a particular variety. Twin

sowing a hardseed pasture (unscarified) with a wheat crop reduces the number of machinery passes required to establish the crop and pasture and therefore fuel and sowing costs are reduced and potentially the number of in-crop sprays too.

Biserrula is high quality feed with serradella also with high crude protein content (Table 1) where lambs are expected to grow from 150-300 g/hd/day liveweight (Dunlop et al. 2003).Table 1. Biserrula feed value. (from Loi et al. 2010)

Component Vegetative Reproduction Senesced

Dry matter digestibility %

81 76 63

Metabolisable energy (MJ/kg DM)

11.7 10.9 8.7

Crude protein % 28 17 13

Neutral detergent fibre %

22 25 45

Acid detergent fibre %

15 16 30

These pastures have a high seed set when compared with traditional subterranean clover (Figure 4).

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Bringing it together

There are large opportunities for sheep producers to increase ewe fertility and weights with the use of improved legume pastures. Biserrula and serradella have moderate to high hardseed levels and have outperformed subterannean clovers in herbage production and seed set at Greenethorpe in the last few years. They also show a strong ability to integrate with a cropping program, providing N and high quality legume


feed and reduce sowing costs. With a longer growing season producers have more flexibility. Joining time and planning for the greatest feed availability can have a significant effect on reproductive performance (King et al. 1998).

The addition of new annual pastures allows producers to extend their feed availability, extend joining and lambing times and alters the pasture production curve. This would also allow producers more flexibility in their programs to better chase markets in lambing times, but also in finishing stock to meet market specifications and turn off more kilograms of lamb per hectare. Some of these plants are a bit unpalatable during flowering and encourage stock to graze weed plants instead of crop at this time. This is also usually at the top of the feed surplus in spring, if left plants will seed and be very palatable again. There is also an issue with photosensitivity with biserrula cv. Casbah (Loi et al. 2005) at particular times similar to grazing canola crops.

ReferencesCraig A (2005) Serradella fact sheet PIRSA http://outernode.

pir.sa.gov.au

Curtis K (2009) Australia’s declining sheep flock. www.sheepcrc.org.au Department of Agriculture, Western Australia.

Dunlop L, McLennan N, Johnson B, Lloyd D (2003) Livestock nutrition sown pastures and fodder crops for prime lambs. Qld DPI&F.

Fogarty NM (1984a) Lamb Production and its Components in Pure Breeds and Composite Lines. I. Seasonal and Other Environmental Effects. Journal of Animal Science 58 (2), 285−300.

Fogarty NM (1984b) Lamb Production and Its Components in Pure Breeds and Composite Lines. II. Breed Effects and Heterosis. Journal of Animal Science 58 (2), 301−311.

Hall DG (1984). Importance of ewe reproduction in the efficiency of lamb production. Journal of Animal Production in Australia 15, 66−69.

King CF, Hopkins DL, Williams PM (1998) Reproductive performance of Border Leicester x Polwarth ewes with and without the Booroola gene (FecB). Animal Production in Australia 22, 225−228. (DPI, Tasmania)

Loi A, Revell C, Nutt, B (2005) Casbah and Mauro biserrula: persistent pasture legume for Mediterranean farming systems. Farmnote No 37/2005. Department of Agriculture, Western Australia

Loi A, Hogg, N, Nutt B, Revell C, Fedorenko D (2010) Growing biserrula to improve grain and livestock production. Department of Food and Agriculture Western Australia Bulletin 4805.

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Contributed papers


Bioscapes − an introduction to biodiversity in grazing landscapesC. Edwards

Department of Primary Industries, Ring Road Armidale 2351; [email protected]

Abstract: This paper reviews a new course ‘Bioscapes – an introduction to biodiversity in grazing landscapes’, developed by the Department of Primary Industries. The course was developed primarily for landholders in response to a need to look at biodiversity principles and how they interact with agricultural production goals. It was also a response to a perceived lack of agricultural context being applied to some biodiversity advice that was being provided to landholders. It is a two-day workshop, delivered on-farm with a mixture of theory and practical examples. The workshop recognises and supports the influence that practical engagement can have in enhancing the knowledge of landholders on this topic.

Key words: workshops, biodiversity, agri cultural production

BackgroundIt is now recognised that the conservation of biodiversity in agricultural landscapes has several benefits for sustainable and resilient landscapes and communities. Managing a grazing landscape for multiple purposes is a challenging undertaking. Increasingly, landholders are asked, and desire to manage agriculture production with environmental outcomes across their landscapes ranging from a small remnant patch to a collective outcome across a catchment.

Landholders are also asking about the relationship between agricultural production and biodiversity principles. There is a desire to know more about ecosystem services and how to maintain them. This was evidenced by enquires to Department of Primary Industries (DPI) on combining field days, talks and information sessions to include not just biodiversity, but biodiversity and agriculture. After conducting a needs assessment of DPI staff, it was seen that there was potential to develop and deliver a workshop on biodiversity and agriculture. In 2009, a producer survey in the Armidale district also revealed that biodiversity was ranked fifth out of 10 natural resource management concerns (C Edwards 2009, unpublished data).

At the time, there was also recognition of several well-resourced research projects and their publications (e.g. Dorrough et al. (2008))

and the Native Vegetation and Biodiversity Program theme in Land, Water and Wool project), which led to the decision that extension of this information was important. Extension in a form that was non-threatening and based on adult learning principles was seen as essential. The development also came about as a shift in thinking that was occurring in the agricultural communities (Dorrough et al. 2008) and acknowledgment of the importance of biodiversity. The course also recognises the findings that biodiversity (and conservation) can have financial benefits in agricultural systems, perceived to be important by Lindenmayer et al. (2011).

The Bioscapes conceptBioscapes is a new two-day workshop focusing on biodiversity in agricultural landscapes. It follows the premise that, while agricultural communities are part of the problem, they are also part of the solution when addressing conservation (~70% of New South Wales is managed for agricultural production purposes). The workshop also raises awareness of the many facets of biodiversity and what they can do for agricultural production systems.

Agronomists and project officers from DPI developed Bioscapes and piloted the workshop in a number of Tablelands locations. Whilst initially aimed at extensive grazing areas of the Tablelands, it is flexible enough to be used in other areas such as coastal environments and cropping zones. It has also been delivered as a



training opportunity for DPI and other agency staff.

The Bioscapes workshopThe two days of the workshop are usually spaced a couple of weeks apart. It contains a mixture of theory and practical exercises. These are primarily aimed at increasing awareness of the terms and definitions used in describing biodiversity by both the agricultural and environmental communities. Topics covered include: ‘What is biodiversity and why is it important’; ‘What is a definition of a healthy, biodiverse landscape’; ‘Can biodiversity and agricultural production goals exist in a landscape’; ‘What are some of the known biodiversity indicators and benchmarks and how might we measure them’; ‘Climate change and biodiversity and ecosystem services’; ‘What are the incentives and programmes that exist for encouraging and affecting biodiversity in our landscapes’. Designed as a small workshop, Bioscapes is ideal when the group size is around 15 participants, as this maximises the group learning experience. The mix of theory and practical outside activities strengthens the delivery of the main messages.

Participants are supplied with a manual and two booklets on ‘Nature Conservation on Farms’ (George and Brouwer 1996) and ‘Vegetation survey and assessment’ (Bayley and Brouwer 2004). Participants are asked to fill in a pre- and post-course questionnaire to determine their attitudes and changes in knowledge. The workshop is currently undergoing alignment with National competency standards.

DiscussionPilot workshops held in Tableland areas in 2010 received positive feedback and suggestions about the format. All workshop participants who responded to the final survey said that they would use some of the information discussed at the workshop on their property. Sixty seven percent of respondents said the workshop was ‘excellent’, with the remainder describing it as ‘good’. Participants included landholders, producers, and Catchment Management Authority staff, as well as Landcare staff and

university students. There was a 61% increase in participants strongly agreeing with the statement ‘can landholders manage for production and biodiversity?’ Many of the positive evaluation comments centred around the mix of theory and field work, the presentation style and the ability to deliver concepts of landscape and ecosystems.

The workshop promotes better land use, land capability and conservation values. It also develops an understanding of how agriculture can both benefit from, and assist with improved biodiversity. The value of Bioscapes is that it provides the appropriate context and helps form an agreed understanding of the terminology used by both sectors thereby improving the quality of the message. Bioscapes is a workshop that helps land managers learn more about the linkages between biodiversity and agricultural production.

AcknowledgmentsThe author gratefully acknowledges the support of DPI team members: L McWhirter, H Rose and L Bowman.

ReferencesBayley D, Brouwer D (2004) Vegetation survey and

assessment. (CB Alexander Agricultural College, Tocal, Patterson, NSW)

Dorrough J, Stol J, McIntyre S (2008) Biodiversity in the Paddock: a Land Managers guide. (Future Farm Industries CRC)

George D, Brouwer D (1996) Nature Conservation on Farms. (CB Alexander Agricultural College, Tocal, Patterson, NSW)

Lindenmayer D, Archer S, Barton P, Bond S, Crane M, Gibbons P, Kay G, MacGregor C, Manning A, Michael D, Montague-Drake R, Munro N, Muntz R, Stagoll K (2011) What Makes a Good Farm for Wildlife? (CSIRO Publishing, Australia)


Surveys of grazing industry end-users in northern New South WalesG.M. Lodge

Department of Primary Industries, Tamworth Agricultural Institute, 4 Marsden Park Road, Calala NSW 2340; [email protected]

Abstract: Three groups of potential end-users in the EverGraze northern NSW project (graziers, leading graziers and advisors) were surveyed. Average property size was 1140 ha with 34% of respondent’s properties being occupied by unimproved native grass and timbered country. Sixty eight percent of all graziers surveyed had both sheep and cattle; 7% had sheep only. About one-third of grazier respondents produced lambs (mainly from self-replacing Merino flocks) solely from native perennial grass-based pastures that did not receive any fertiliser or legume inputs with little or no supplementation provided. All of the leading graziers and advisors thought that such pastures were suitable only for wool production and store stock. The two least adopted yet widely recommended practices were objectively measuring pasture herbage mass and the use of fodder budgets, although practices such as fat scoring and using soil tests were also often rarely used on-farm. Differences in practices recommended by advisors and their perceived/actual adoption by graziers suggested that extension messages were not impacting as expected. This needs to be taken into account when designing and implementing future extension programs.

Key words: sheep, cattle, pastures, pasture improvement, natural resource management, management practices

IntroductionSurveys were undertaken in 2008 and 2009 of grazier, leading grazier and advisor groups in northern inland New South Wales (NSW). While these groups were major potential end-users for information from the EverGraze northern NSW project (Lodge et al. 2008), little was documented about the regional demographics, pasture and animal production systems, current management practices, levels of animal production and pasture improvement, the use of fertilisers, forages and supplements and producers’ attitudes and perceptions towards production, farm profitability and natural resource management (NRM) issues. Some of this information was being collected on a limited number of individual properties as part of an on-farm monitoring process within the EverGraze northern NSW project (Lodge et al. 2011), but a broader information base was required to be able to use such knowledge to plan and develop future key messages and extension programs. Where feasible, common questions were directed to the three groups to provide insights into current practices recommended by advisors and their actual and perceived levels of

adoption, and to highlight any potential barriers to the more widespread use of management practices to improve profitability and enhance NRM among graziers in northern NSW.

The survey area was primarily the eastern section of the Namoi Catchment and the south-eastern portion of the Border Rivers-Gwydir Catchment, which was also the main area of focus for the EverGraze Proof Site project in northern NSW (Lodge et al. 2008; Lodge et al. 2011). A large proportion of this area was previously surveyed in the mid 1980s by Lodge et al. (1991), but since that time anecdotal evidence indicated a marked decline in the regional forage base as a result of dry years (e.g. Lodge and McCormick 2010), a substantial increase in cattle numbers, a decline in wool production from sheep, and an increased use of summer-growing native perennial grass-based pastures for fattening and breeding enterprises rather than their traditional use of grazing store stock. A similar survey of sheep producers in the Mallee district of Victoria (Robertson and Wimalassuriya 2004) reported that recommended practices that could increase farm productivity were not being adopted and suggested that this was a nation-wide issue which needed to be addressed. These authors also highlighted a lack of regional benchmark values for pasture and livestock enterprises and


this was also addressed in the current EverGraze northern NSW project (Lodge 2011).

This paper aims to quantify the current level of activity and knowledge, document trends and attitudes in the grazing industries for pasture and livestock production, and to provide an assessment of the perceived importance of a range of environmental issues in northern NSW. It was intended that this information would then be of benefit when designing future key messages and extension programs within the EverGraze project in northern NSW.

MethodsThree separate surveys were developed for graziers, leading graziers and public and private sector advisors consisting of up to 62 questions with commonality among many of the questions. Questions covered not only the physical aspects of the property (areas of different pastures and forages, livestock types and numbers and enterprises), but also attitudes to pastures, forages, supplements and fertiliser use, current pasture/forage use, animal production (both sheep and cattle), and NRM. Numbers of survey respondents were 51 for the general grazier survey, 12 for the leading grazier group (as identified by peers and advisors) and eight for the advisor group.

Results and discussionAnalysis of all responses indicated that:• Averagepropertysizewas1140ha.• Average producer agewas 53 years (only

25% of respondents expected that one of their children may take over the running of the property).

• On average unimproved native grassand timbered country occupied 34% of respondent’s properties.

• Proportions of different pastures andforages were: native pastures oversown with subterranean clover and superphosphate (15%), lucerne (5%), sown pastures (3.2% temperate grasses and 2.1% tropical grasses), grazing cereals (5%) and summer forages (1%).

• 68%ofallgrazierssurveyedhadbothsheepand cattle; 7% had sheep only.

• 38%ofsheepproducershadself-replacingMerinos, mostly producing <21 micron wool.

• Averagewoolcutwas4.7kg/headforwethersand 4.6 kg/head for ewes.

• 44%of respondentswith sheepproducedlambs for meat production (22% Merino ewes, 22% crossbred ewes).

• Most respondents with cattle (61%) hadbreeding cows, producing weaners (23%), yearlings (27%) or steers (32%).

About one-third of grazier respondents produced lambs (mainly from self-replacing Merino flocks) solely from native perennial grass-based pastures that did not receive any fertiliser or legume inputs with little or no supplementation provided. In contrast, all leading graziers and advisors thought that such unimproved native perennial grass-based pastures were suitable only for wool production and store stock. Leading grazier respondents also had higher proportions of lucerne, forage oats and native pastures oversown with subterranean clover than the grazier respondents and they also had up to 20% higher lambing and weaning percentages. A high proportion of grazier respondents (43%) indicated that they intended getting out of sheep production in the next five years, compared with only 16% of leading graziers.

Commonality of questions in the advisor, leading grazier and grazier surveys showed a marked divergence between what was recommended practice, adopted by leading graziers and undertaken by most graziers (Table 1). Soil testing, for example was recommended by all advisors, but used by only 57% of leading graziers and 50% of graziers surveyed, with about half of these only undertaking a soil test every 5-10 years. Similarly, although fat scoring was widely recommended, it had been adopted by only two-thirds of the leading graziers surveyed and 42% of the grazier respondents. Even simple practices such as providing ewes with a higher plane of nutrition at joining (‘flushing’) had been adopted by only about three-quarters of graziers surveyed (Table 2). Apparent high adoption


of the use of supplements and application of fertilisers was related to the widespread use of salt blocks as a pasture ‘supplement’ and the infrequent application (1 year in 5) of low rates of superphosphate to pastures. Most respondents indicated that they grazed strategically, moving stock based on pasture availability or animal requirements (28%), rotationally grazed or regularly moved stock to rest pastures (24%) or used a combination of set stocking (same mob of animals in the same paddock for most of the year) and strategic grazing (20%).Table 1. Percentage responses by advisors, leading graziers and graziers to questions about profit motivation and feed quantity/quality limiting animal production.

Advisors Leading graziers

(%)

Graziers

Motivated by profit 70 55 40

Production limited by feed quantity/quality

77 63 65 (36A)

A Graziers with sheep only.

The two least adopted yet widely recommended practices were objectively measuring pasture herbage mass (about one-third of all producer respondents) and the use of fodder budgets (<10% of all graziers). This is somewhat surprising given that more than 63% of graziers thought that feed supply or climate variability and drought were the main limitations to farm profit (Table 1). Decisions about stock movements were mostly based on visual assessments of herbage mass and height (45%) or ground cover (28%). Decisions

about when to graze a pasture were made mainly on visual assessments of pasture condition (49%) or quality (27%). Although 42% of the grazier respondents said that they regularly used fat scoring, only 4% indicated that it was a major factor in assessing the condition of their animals; 24% used a visual assessment of fat cover on the ribs, 20% used animal contentment and general appearance and 15% judged animal condition by looking at the condition of the pasture. While 33% of all grazier respondents said that they regularly assessed pasture herbage mass, only 5% indicated that they used it to decide when to graze a pasture. Low proportions of grazier respondents used fodder budgets (2.6%) or calendar-based systems (1.3%) to decide when to graze. These results occurred despite more than 70% of the grazier respondents having attended a ProGraze course and indicated that there was a strong preference for graziers to use experientially learnt visual guides applicable to their individual properties, rather than objective measurements and known regional benchmark values.

Major limitations to increasing farm profit were perceived to be lack of capital (21%), feed supply (23%), droughts (19%) and climate variability (21%). To improve profitability the most popular pasture management practices nominated were to increase legume content (22%), apply additional fertiliser (20%) and sow more perennial grasses (21%). The most popular animal management practices to improve profitability included improving genetics (16%),

Table 2. Percentage of advisors that recommended different management practices and the proportion of leading grazier and grazier respondents that have adopted these practices, together with advisor and leading grazing estimates of the perceived level of adoption.

Management practiceAdvisors Leading graziers Graziers

% recommended

Perceived % adoption

Assessed % adoption

Perceived % adoption

Assessed % adoption

Use supplements 100 50−70 85 50−70 79

Apply fertiliser to pastures 100 <30 100 <30 83

Use a soil test 100 – 57 – 51

Use fat scoring 85 <30 66 – 42

Flush ewes at joining 85 <50 88 <10 73

Objectively measure herbage mass 100 <10 33 <10 36

Use fodder budgets 85 <10 10 <10 9


increasing lambing/calving percentages (11%), increasing weaning percent (11%) and changing marketing methods (10%).

Most graziers thought that soil health (24%), water availability (14%), lack of perennial species (14%), soil erosion (13%) and global warming/climate change and biodiversity (both 13%) were the major environmental issues for the region. However, on-farm the major environmental issues were ground cover (26%), a lack of perennial species (15%), shrub and tree invasion (14%), tree cover (13%) and soil erosion (12%). Thirty nine percent of graziers indicated that they would tolerate up to a 5% loss of production to increase biodiversity, while 32% indicated that they would prefer no loss of production. Most grazier respondents (91%) expressed a strong conservation and land stewardship ethic, but many (80%) thought that the cost of looking after the environment should be more equitably shared by the non-rural sector.

Responses by advisors, leading graziers and graziers to questions on profit and the major factors limiting animal production were markedly different (Table 1). For example, while most advisors thought that all graziers were motivated by profit and that feed availability, feed quality and feed supply/demand limited animal production, a lower proportion of graziers thought similarly. Surprisingly, only 36% of sheep producers indicated that feed availability/quality or feed supply/demand limited animal production, with other responses being the high costs of production (11%), low wool prices (11%), labour constraints (14%), increasing producer age (5%) and the higher profitability of alternative livestock types (6%).

Differences in practices recommended by advisors and their perceived or actual adoption by graziers and the marked variation in responses to profit motivation and factors limiting animal production suggested that extension messages were not impacting as expected. This will need to be taken into account when designing and implementing future extension programs. Similarly, the contrasting differences in regional and on-farm environmental issues have implications for how future programs that impact on NRM are packaged.

AcknowledgmentsEverGraze is a Future Farm Industries CRC, Meat & Livestock Australia and Australian Wool Innovation research and delivery partnership. The Department of Primary Industries (formerly Industry & Investment NSW) is a core partner of the Future Farm Industries CRC. All respondents to the surveys are thanked for their input and interest.

ReferencesLodge GM (2011) Developing pasture and livestock

benchmarks for sheep production in northern New South Wales. In ‘Proceedings of the 26th annual conference of the Grassland Society of NSW.’ (Eds G Lodge, J Scott, W Wheatley). pp. 116 (Grassland Society of NSW Inc.: Orange)

Lodge GM, McCormick LH, Dadd CP, Burger AE (1991) A survey of graziers and pasture management practices on the Northern Slopes of New South Wales. NSW Agriculture & Fisheries, Technical Bulletin No 43.

Lodge GM, Boschma SP, Brennan MA (2008) EverGraze research in northern New South Wales. In ‘Proceedings of the 23rd Annual Conference of the Grassland Society of NSW’. (Eds SP Boschma, LM Serafin, JF Ayres). pp. 133−134. (NSW Grassland Society Inc.: Orange)

Lodge GM, McCormick LH (2010) Comparison of recent, short-term rainfall observations with long-term distributions for three centres in northern New South Wales. In ‘Proceedings of the 25th annual conference of the Grassland Society of NSW.’ (Eds C Waters, D Garden). pp. 104−107. (Grassland Society of NSW Inc.: Orange)

Lodge GM, Brennan MA, Sanson PT, Roworth BR, Stace IJ (2011) On-farm monitoring of sheep and pasture production in the EverGraze northern New South Wales project. In ‘Proceedings of the 26th annual conference of the Grassland Society of NSW.’ (Eds G Lodge, J Scott, W Wheatley ). pp. 112 (Grassland Society of NSW Inc.: Orange)

Robertson SM, Wimalassuriya RK (2004) Limitations to pasture and sheep enterprises and options for improvement in the Victorian Mallee. Australian Journal of Experimental Agriculture 44, 841−849.


On-farm monitoring of sheep and pasture production in the EverGraze northern New South Wales project

G.M. Lodge, M.A. Brennan, P.T. Sanson, B.R. Roworth and I.J. Stace


Abstract: For commercial sheep mobs monitored in 2008 and 2009 as part of the EverGraze project on the North-West Slopes of New South Wales, there was a significant (P < 0.05) linear relationship between lamb weaning percentage and ewe fat score throughout the reproductive cycle. In both years, correlation coefficients were highest for ewe fat scores at joining. There were no significant relationships between green herbage availability in five different periods throughout the reproductive cycle and ewe fat score at the end of each period. However, for all of the native perennial grass pastures monitored the available green herbage mass was below the minimum benchmark level for spring lambing ewes in the critical June to September period. Our data reinforced the need to integrate native grass pastures with paddocks of either lucerne or forage oats and/or the provision of adequate protein and energy supplements to achieve high weaning percentages.

Key words: green herbage mass, ewe fat score, weaning percentage, native pastures

IntroductionPrevious studies of native perennial grass-based pastures on the North-West Slopes of New South Wales (NSW) have shown that these grasslands were low productivity pastures, best suited to wool production and store cattle (Lodge and Roberts 1979; Lodge and Whalley 1983, 1989; Lodge et al. 1991; Lodge 2011). However, in response to variable and mostly dry seasons, low wool prices and declining sheep numbers in the region over the past 20 years, native pastures are increasingly being used in both sheep and cattle breeding enterprises. Based on known forage quality and seasonal growth rates for both C3 and C4 native perennial grasses (Lodge and Whalley 1983, 1989; McDonald 1996) it is highly unlikely that most native perennial grass-based pastures would be able to meet the protein and energy requirements of breeding livestock, unless their use on-farm was integrated with other forage sources such as oversown subterranean clover (Trifolium subterraneum), lucerne (Medicago sativa), sown temperate or tropical perennial grass-based pastures, forage oats (Avena sativa), or other forms of supplementation.

A mismatch in the seasonal quality and quantity of the regional pasture base and the known demands for grazing livestock was highlighted

by McDonald and Bell (1995) and Lodge et al. (2003). Further, pasture benchmarks (ProGraze manual 2006) calculated from GrazFeed for the minimum green herbage mass (68% digestibility) required to maintain satisfactory production levels in sheep, clearly indicated the inadequacy of most native perennial grass pastures, particularly in winter-early spring. These values are 600 kg of green dry matter (DM)/ha for dry sheep, 700 kg DM/ha for ewes in mid-pregnancy, 1200 kg DM/ha for those in the last month of pregnancy and 1700 kg DM/ha for lactating ewes. Green herbage with a digestibility of 60% was not considered suitable for ewes in late pregnancy or for lactation. For these benchmarks, pastures were assumed to have 500 kg DM/ha of dead material (47% digestibility) and a legume content of 15%.

In the current study, we used on-farm data from the North-West Slopes of NSW to examine the relationship between green feed availability, ewe fat score and sheep performance. Fat scoring (White and Holst 2006) is a simple, objective measure to assess livestock condition that can provide information on the adequacy of feed supply. The reported study was part of the National EverGraze program in northern NSW designed to increase the profitability of sheep producing properties (Lodge et al. 2008). While the focus of this paper is the relationship between lamb weaning percentages and ewe


fat scores and pasture green herbage mass at different stages of the ewe reproductive cycle, the process of on-farm data collection also provided a unique opportunity to observe some day-to-day practices.

MethodsIn both 2008 and 2009, up to 15 commercial properties were monitored to gather on-farm data related to ewe production and pasture/forage systems. For individual sheep mobs on each property (23 in 2008 and 21 in 2009), data were collected on weaning percentage (the number of lambs weaned as a proportion of the total number of ewes joined) and mean ewe fat score, assessed on 40 randomly selected ewes in each mob.

Pasture or forage paddocks that were grazed by a sheep mob were assessed every time the mob entered or was removed from each paddock. If animals remained in a paddock for an extended period, then samples were taken at 6 weekly intervals. At theses times total herbage mass, the proportion of green (green herbage mass), the proportion of sown species, litter mass and ground cover were assessed. Since native perennial grass pastures were the focus of the EverGraze project in this region, these were the dominant pasture type sampled, together with lucerne and forage oats.

These data were used to explore the relationships between lamb weaning percentage in 2008 and 2009 and ewe fat score at joining, 100 days pregnancy, pre-lambing (~1 month), lamb marking and weaning, and the available green herbage mass (kg DM/ha) for Merino ewes joined to Merino or terminal sires and lambing in spring. In both years, the mean green herbage mass available to each mob was calculated for the following periods: lamb weaning to ewe joining; joining to 100 days pregnancy; 100 days pregnancy to pre-lambing; pre-lambing to lamb marking, and marking to weaning. Data were excluded from the linear regression analyses if the green herbage mass was mainly stem material and so unlikely to have a digestibility greater than the required 68% (ProGraze manual 2006). Similarly, data for sheep mobs that were fed hay,

grains or pelleted feeds were also excluded from the regression analyses. Fat score data were also grouped for different pasture types to examine their effect on lamb weaning percentage.

Results and discussionIn both 2008 and 2009, the linear relationship between ewe fat score at each sampling time and lamb weaning percentage (Table 1) was always significant (P <0.05), with the correlation coefficient (r) ranging from 0.73 (lamb marking in 2008) to 0.95 (joining in 2008). However, in both years there was no significant relationship between mean green dry matter available in each period and weaning percentage, with the r-value always being <0.34 (data not presented). The relationship between ewe fat score at the end of a period and the green herbage mass available in that period was also not significant for fat scores taken at joining, 100 days pregnancy, pre-lambing, marking and weaning (r-value <0.41, data not presented).

These data indicated a strong correlation between ewe fat score throughout the reproductive cycle and lamb weaning percentage, with the relationship being strongest at joining in each year (Table 1). Clearly, ewes with high fat scores at joining had higher conception rates, which led to high lamb weaning percentages, with a fat score of 3.5 [the mid-point of the recommended fat score range at joining (Johnson 2005)] indicating a potential mean lamb weaning

Table 1. Linear relationships between ewe fat score (X) taken at five times throughout the reproductive cycle in sheep mobs and lamb weaning percentage (Y) in 2008 and 2009.

Year

Fat score 2008 2009

Joining Y = 25.7X-5.8 R2 = 0.90

Y = 41.2X-49.9 R2 = 0.77

100 days pregnancy

Y = 31.6X-12.5 R2 = 0.76

Y = 30.3X-0.7 R2 = 0.62

Pre-lambing Y = 21.3X+24.9 R2 = 0.77

Y = 32.6X-2.6 R2 = 0.61

Lamb marking Y = 17.8X+30.9 R2 = 0.54

Y = 38.7X-18.5 R2 = 0.57

Weaning Y = 18.3X+32.4 R2 = 0.60

Y = 38.5X-17.8 R2 = 0.55


percentage of 84% for the mobs scored and conditions experienced in 2008, and 95% for those in 2009.

Initially, the lack of a relationship between fat score at the end of a period and green herbage mass availability in that period appeared to be inconsistent with the expected outcome. However, closer examination of the data indicated that the required benchmark levels for green herbage mass, particularly in late pregnancy and lactation, were never met by the native grass pastures, and were only met by lucerne and forage oat paddocks on a few properties. Although total annual rainfall in 2008 and 2009 across the North-West Slopes of NSW was generally average or above average, autumns were very dry (Lodge and McCormick 2010), with autumn rainfall in Tamworth, for example, being 74 and 46% below average in 2008 and 2009, respectively. These dry conditions combined with low temperatures in winter, reduced the available green herbage mass of native pastures dominated by frost-sensitive C4 grasses to generally <300 kg DM/ha in the critical June to September period and on these pastures lamb weaning percentages were 44−78%. Clearly, in both years, only those producers who had paddocks of lucerne or forage oats, or provided adequate levels of energy and protein supplementation in late pregnancy,

were able to achieve weaning percentages >85% (Table 2).

In regard to day-to-day practices, many producers tended to combine and split sheep mobs throughout the year making it difficult to accurately keep track of stock numbers. Often paddock sizes were not known, none of the cooperating producers counted live lambs born and several different methods were used for calculating basic production statistics such as lambing and weaning percentages. Hence, conventional production measures such as stocking rate, ewe fecundity and lambing percentage were often not regarded by producers as metrics useful to their business. Methods of calculating lambing, marking and weaning percentages also need to be standardised so that they are comparable. Some producers were aware of the ProGraze green herbage mass benchmarks and the differing animal nutritional requirements throughout the reproductive cycle and actively managed to provide lucerne, forages and supplements to meet any deficits. Sowing of oats in late summer rather than late autumn was a useful strategy used by successful producers. No graziers on the properties monitored used fat scoring on a regular basis, and most used experiential knowledge rather than objective measurements to make grazing decisions. On many properties there was a constant conflict

Table 2. Mean ewe fat scores and lamb weaning percentages in 2008 and 2009 for a good native pasture (GNP, a mixture of C3 and C4 grasses, fertiliser applied and legume oversown and/or supplements used), a predominantly lucerne/forage oat system, a poor native pasture (PNP, predominantly C4 grasses with lucerne and/or supplements used) and a unfertilised PNP. Values are meaned across mobs and farms.

Pasture type Ewe fat scores

Weaning Joining 100 days Pre-lambing

Marking Weaning Weaning (%)

2008

GNP+fert+supplements 3.2 3.5 3.2 3.0 3.3 2.9 85

Pred. lucerne/forages 3.8 4.4 4.2 4.2 3.7 4.4 112

PNP+lucerne+supplements 3.7 4.3 4.3 2.7 3.8 3.7 89

Poor NP 3.0 3.2 2.5 2.3 2.7 2.6 72

2009

GNP+fert+supplements 2.9 3.2 3.0 2.7 2.6 2.8 79

Pred. lucerne/forages 4.4 4.2 4.4 3.9 3.4 3.6 112

PNP+lucerne+supplements 3.7 3.7 3.1 3.0 3.1 3.0 109

Poor NP 2.5 2.9 2.6 2.4 2.4 2.3 70


between the use of quality, green feed for cattle production and its availability for ewes and lambs, with the cattle often winning out. Successful sheep producers tended to confine joining to a 6−8 week period, sell trade quality lambs (~45 kg liveweight) using contracts and to scan ewes at 80−90 days pregnancy to detect dry, single and multiple lamb bearing ewes and to use this knowledge to make informed management decisions.

AcknowledgmentsEverGraze is a Future Farm Industries CRC, Meat & Livestock Australia and Australian Wool Innovation research and delivery partnership. The Department of Primary Industries (formerly Industry & Investment NSW) is a core partner of the Future Farm Industries CRC. We gratefully acknowledge the interest and assistance of the cooperating landholders involved in the EverGraze northern NSW project.

ReferencesJohnson P (2005) What are the fat score targets to aim for

and when? New South Wales Lifetime Wool Volume 1, Issue 3. (Ed. S Hartcher). (Department of Primary Industries: Orange)

Lodge GM (2011) Developing pasture and livestock benchmarks for sheep production in northern New South Wales. In ‘Proceedings of the 26th annual conference of the Grassland Society of NSW.’ (Eds G Lodge, J Scott, W Wheatley). pp. 116 (Grassland Society of NSW Inc.: Orange)

Lodge GM, Roberts EA (1979) The effects of phosphorus, sulphur and stocking rate on the yield, chemical and botanical composition of natural pasture, North-West Slopes, New South Wales. Australian Journal of Experimental Agriculture and Animal Husbandry 19, 698−705.

Lodge GM, Whalley RDB (1983) Seasonal variations in the herbage mass, crude protein and in vitro digestibility of native perennial grasses on the North-West Slopes of New South Wales. Australian Rangeland Journal 5, 20−27.

Lodge GM, Whalley RDB (1989) Native and natural pastures on the Northern Slopes and Tablelands of New South Wales: a review and annotated bibliography. NSW Agriculture & Fisheries, Technical Bulletin No. 35.

Lodge GM, McCormick LH, Dadd CP, Burger AE (1991) A survey of graziers and pasture management practices on the Northern Slopes of New South Wales. NSW Agriculture & Fisheries, Technical Bulletin No. 43.

Lodge GM, Murphy SR, Harden S (2003) Effects of grazing and management on herbage mass, persistence, animal production and soil water content of native pastures. 1. A redgrass-wallaby grass pasture, Barraba, North-West Slopes, New South Wales. Australian Journal of Experimental Agriculture 43, 875−890.



McDonald W, Bell A (1995) Selecting the right pastures to meet the market. In ‘Proceedings of the 10th annual conference of the Grassland Society of NSW’. (Eds JF Ayres, DL Michalk, HL Davies). pp. 43−50. (NSW Grassland Society Inc.: Orange)

McDonald W (1996) Matching pasture production to livestock enterprises in the Northern Tablelands and North West Slopes and Upper Hunter. AgNote DPI/139. (NSW Agriculture: Orange).

ProGraze manual (2006) ProGraze – profitable, sustainable grazing. (Ed. B Noad). (NSW Agriculture, Orange and Meat & Livestock Australia, Sydney)

White A, Holst P (2006) Fat scoring sheep and lambs. Primefact 302. (NSW Department of Primary Industries: Orange). Also available at: http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0015/96000/fat-scoring-sheep-and-lambs.pdf

http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0015/96000/fat-scoring-sheep-and-lambs.pdf




Developing pasture and livestock benchmarks for sheep production in northern New South Wales

G.M. Lodge


Abstract: Focus groups of agency and commercial advisors were used to obtain information on stocking rates and the value of different pasture types for different livestock enterprises in northern New South Wales. A simple spreadsheet-based feed calculator that utilised the livestock months (LSM) concept, where 1 LSM = 250 Megajoules of energy per 30-day month, was used to assign monthly values for pasture/forage supply and animal requirements. This provided a useful tool that enabled changes in pasture types/areas and sheep numbers to be rapidly computed, providing a visual output of the likely match between feed supply and animal requirements for a whole farm.

Key words: native pastures, forage oats, lucerne, tropical perennial grasses, stocking rates, feed calculator

IntroductionUnfertilised native perennial grass-based pastures are increasingly being used for both sheep and cattle breeding and fattening in northern New South Wales (NSW), despite their unsuitability for these enterprises (Lodge and Roberts 1979; Lodge and Whalley 1983, 1989; Lodge et al. 1991; ProGraze manual 2006). In a survey of advisors and leading graziers on the North-West Slopes of NSW (Lodge 2011), all of the respondents indicated that native perennial grass-based pastures were not suited to breeding and fattening, unless their use was integrated with other forage sources or supplements were provided. However, on 55% of the properties monitored as part of the EverGraze northern NSW project (Lodge et al. 2008) native grass pastures were either the sole or primary forage source for these enterprises.

Native pastures dominated by C4 summer-growing, frost susceptible grasses commonly have a ‘protein and energy’ deficit in the critical later winter-early spring period that coincides with mid to late pregnancy for stock calving or lambing in spring. At this time of the year these species are physiologically unable to meet the benchmark requirements for green herbage mass and quality (ProGraze manual 2003). To meet these requirements in most years native pastures require a substantial component of C3

winter-growing native perennial grasses and/or oversown annual legumes such as subterranean clover (Trifolium subterraneum) in conjunction with applied fertiliser. Alternatively, the use of these pastures as a feed source may be integrated with paddocks of winter-growing forage oats (Avena sativa). Less often, sown temperate grass-based pastures or supplementation are used on-farm to help meet animal requirements. With summer dominant rainfall in northern NSW, both lucerne and tropical perennial grasses are widely used as summer forage sources (Harris et al. 2010), but the growth of both are limited by colder temperatures in the critical winter period. Below average annual rainfall in the past 10 years (e.g. Lodge and McCormick 2010a) in northern NSW and a shift from wethers to sheep and cattle breeding and fattening enterprises has put considerable pressure on the regional feed base and so, for many on-farm situations, the limitations and carrying capacities of different forage sources and how to match feed supply to animal requirements need to be revisited.

Two activities undertaken within the National EverGraze program in northern NSW (Lodge et al. 2008) helped to address these issues. The first was a series of advisor focus groups that provided benchmark values for different pasture/forage types, while the second was the development of a simple spreadsheet calculator, based on the livestock month (LSM) concept used in COMPLAN (Buffier and Young 1977), a computerised farm planning service popular in northern NSW in the 1970s and 1980s. This paper reports the outcomes from the focus groups and


demonstrates how a basic knowledge of feed quality and animal requirements can assist with forage budgeting and grazing management.

MethodsThree focus groups for agency and commercial advisors (both agronomy and livestock) were held in 2007−08 and consisted of written responses to questions that were supplementary to the main EverGraze survey undertaken by Lodge (2011) and a structured discussion about stocking rates and the use of different pasture types and forage sources. A summary of the main outcomes including expected stocking rates for different pasture types is reported in Table 1. Stocking rates (Table 1) are expressed on a dry sheep equivalent (DSE) basis with 1 wether/ha = 1 DSE/ha; 1 ewe-lamb/ha = 2 DSE/ha; 1 steer/ha = 10 DSE/ha, and 1 cow-calf/ha = 15 DSE/ha. These values are subjective rankings of the annual (12-month) energy requirements of the different classes of livestock relative to the energy requirements of a 50 kg liveweight adult dry sheep which is equivalent to 1 DSE/ha.

The feed calculator is based on a LSM, which is defined as the energy required to maintain a 50 kg dry sheep grazing a ‘medium quality pasture’ for a month (30 days), after allowing for an amount of 35% of the fasting metabolism for exercise (Rickards and Passmore 1971). In energy terms, a LSM is equivalent to 250 Megajoules (MJ) per month or 8.33 MJ per day. Livestock month values were calculated seasonally and monthly by Buffier and Young (1977) for a wide range of crops, forage crops and pastures grown on the North-West Slopes and northern Tablelands of NSW, as well as for all of the major sheep and beef cattle enterprises. These values were also used by Lodge and Frecker (1990) in devising a decision support system for whole-farm forage budgeting in northern NSW. The only LSM values not calculated by Buffier and Young (1977) were those for tropical perennial grass pastures and these were estimated from growth curves (ProGraze manual 2006). Livestock month units were also split into ‘general purpose’ (maintenance) and ‘special purpose’ (growth) values to take account of the seasonal differences in feed quality (reflecting the amount

of green and dead herbage) and the differing feed requirements of livestock at different stages of reproduction and lactation.

In the feed calculator, there are LSM values for eight different pasture types; timbered country, poor native pasture (PNP, unfertilised pastures dominated by C4 grasses), good native pasture (GNP, fertilised native pasture dominated by C3 grasses), native pasture + subterranean clover (native pasture oversown with subterranean clover and fertilised), improved temperate pasture (sown temperate grass/legume pastures with fertiliser applied), lucerne, forage oats and tropical perennial grass pastures. All pasture types, except timbered country and PNP were assumed to receive adequate fertiliser application. There are also three different sheep enterprises; wethers, self-replacing Merino ewes and Merino ewes crossed to a terminal sire, with both ewe enterprises lambing in spring. All values were for an ‘average run of seasons’ each year, but could be scaled monthly to allow for seasonal variations. Property size, areas of different pastures and stock numbers can all be varied, but in the reported example a ‘typical farm’, as defined by a local producer group (McCormick et al. 2009), was used with a total area of 400 ha, running 1500 spring-lambing Merino ewes. Graphical outputs (radar graphs) indicate the monthly total metabolisable energy (ME) supplied by the different forage sources and the total ME required by the sheep. Monthly total values are also partitioned into those supplied or required for stock maintenance and growth. Altering the area of different pasture types and/or stocking rates allows the user to instantly visualise changes in feed supply and demand each month and so adjust for any feed deficits or surpluses (which can be used for fodder conservation).

Results and discussionAdvisor focus groups highlighted that unfertilised native perennial grass-based pastures were not suited to breeding or fattening enterprises (Table 1) and that their on-farm use needed to be integrated with other forage sources, including supplements. This point was also reinforced by the data in Figure 1a


Table 1. Expected stocking rate (DSE/ha) of different pasture types/forage sources, together with their suitability for breeding/fattening (the more shaded boxes the better) and comments.

Pasture/forage condition

Expected stocking rate (DSE/ha) Suitability for breeding/

fattening

Comments

Average Minimum Maximum

Native pasture − unfertilised

Poor 1.0 0.5 1.5 Advisors indicated that summer-growing grass pastures are bestsuited to store stock only.

Average 3.1 2.5 5.0

Good 4.3 3.0 5.0

Native pasture + fertiliser + subterranean clover

Poor 3.3 2.5 5.0 Use S-based fertiliser ~every 2 yr. Use mid-late season sub clovers. Sub clover may fail in drier years. Average 5.4 5.0 6.5 ■■

Good 7.8 7.0 9.0 ■■■Temperate perennial grass/legume

Poor 4.8 3.0 6.0 ■ Sow only in favoured areas. Allow tiller development and flowering one year in three. Average 9.3 7.0 10.0 ■■■

Good 13.5 10.0 15.0 ■■■■■Tropical perennial grass

Poor 5.8 5.0 8.0 ■ Rotationally graze to maintain green leaf. Maintain quality by adding legumes or N. Average 9.9 7.0 12.5 ■■

Good 15.0 10.0 20.0 ■■■■Lucerne

Poor 6.3 5.0 10.0 ■ Rotationally graze. Allow plants to flower. Consider using pasture mixtures for good ground cover. Average 9.5 6.0 12.0 ■■■

Good 14.1 7.5 20.0 ■■■■■Forage oats

Poor 8.6 5.0 15.0 ■ Sow in late Feb.−early March. Strip or rotationally graze for best use. Apply N for best response. Average 18.8 10.0 25.0 ■■■

Good 25.8 15.0 30.0 ■■■■■

which indicated that in an average year a 400 ha good native pasture would not meet the ME requirements of 1500 self-replacing Merino ewes from May to mid November (i.e. for 6.5 months) each year. However, the same pasture could carry 1300 Merino wethers/year (a stocking rate of 3.25 DSE/ha) without the need for alternative forage sources or supplementation (data not shown). If, instead of having 400 ha of good native pasture, the farm had 200 ha of good native pasture, 50 ha of fertilised native pasture oversown with subterranean clover, 50 ha of lucerne, 50 ha of forage oats and 50

ha of tropical perennial grass pastures, then it would easily meet the total ME requirements in an average year (Figure 1b), as well as those for growth, pregnancy and lactation of the 1500 ewe breeding flock. A range of pasture/forage types was required to meet the seasonal demands (lucerne in spring-summer, tropical perennial grasses in late summer-autumn and forage oats in late autumn-winter). Also, with a variable climate (e.g. Lodge and McCormick 2010a) different annual, perennial and C3/C4 species can respond to different niches (Lodge and McCormick 2010b).


AcknowledgmentsEverGraze is a Future Farm Industries CRC, Meat & Livestock Australia and Australian Wool Innovation research and delivery partnership. The Department of Primary Industries (formerly Industry & Investment NSW) is a core partner of the Future Farm Industries CRC. The interest and assistance of the cooperating advisors and producers involved in the EverGraze northern NSW project is gratefully acknowledged.ReferencesBuffier BD, Young DF (1977) COMPLAN Handbook No.

1 – Enterprise budgets for the North West of N.S.W. (University of New England: Armidale)

Harris CA, McCormick LH, Boschma SP, Lodge GM (2010) Tropical Perennial Grasses for Northern Inland NSW. (Bookbound Publishing Pty Ltd: Gumma)

Lodge GM (2011) Surveys of grazing industry end-users in northern New South Wales. In ‘Proceedings of the 26th annual conference of the Grassland Society of NSW.’ (Eds G Lodge, J Scott, W Wheatley). pp. 108 (Grassland Society of NSW Inc.: Orange

Lodge GM, Roberts EA (1979) The effects of phosphorus, sulphur and stocking rate on the yield, chemical and botanical composition of natural pasture, North-West Slopes, New South Wales. Australian Journal of Experimental Agriculture and Animal Husbandry 19, 698−705.

Lodge GM, Whalley RDB (1983) Seasonal variations in the herbage mass, crude protein and in vitro digestibility of native perennial grasses on the North-West Slopes of New South Wales. Australian Rangeland Journal 5, 20−27.

Lodge GM, Whalley RDB (1989) Native and natural pastures on the Northern Slopes and Tablelands of New South Wales: a review and annotated bibliography. NSW Agriculture & Fisheries, Technical Bulletin No. 35.

Lodge GM, Frecker TC (1990) FEEDBAL: An integrated expert system for calculating whole-farm forage budgets. Computers and Electronics in Agriculture 5, 101−117.

Lodge GM, McCormick LH, Dadd CP, Burger AE (1991) A survey of graziers and pasture management practices on the Northern Slopes of New South Wales. NSW Agriculture & Fisheries, Technical Bulletin No 43.


Lodge GM, McCormick LH (2010a) Comparison of recent, short-term rainfall observations with long-term distributions for three centres in northern New South Wales. In ‘Proceedings of the 25th annual conference of the Grassland Society of NSW.’ (Eds C Waters, D Garden). pp. 104−107. (Grassland Society of NSW Inc.: Orange)

Lodge GM, McCormick LH (2010b) Long-term annual rainfall and the distribution of simulated annual pasture intake of ewes grazing different pastures on the North-West Slopes of New South Wales. In ‘Proceedings of the 25th annual conference of the Grassland Society of NSW.’ (Eds C Waters, D Garden). pp. 123−126. (Grassland Society of NSW Inc.: Orange)

McCormick LH, Boschma SP, Lodge GM, Scott JF (2009) Producer-identified constraints to widespread adoption of sown tropical grass pastures on the north-west slopes of New South Wales. Tropical Grasslands 43, 263−266.

ProGraze manual (2006) ProGraze – profitable, sustainable grazing. Sixth edition. (Ed. B Noad). (NSW Agriculture, Orange and Meat & Livestock Australia, Sydney)

Rickards PA, Passmore AL (1971) Planning for Profit in Livestock Grazing Systems. Professional Farm Management Guidebook No. 7. (Agricultural Business Research Institute, UNE: Armidale)

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Figure 1. Total metabolisable energy (MJ/month) required by 1500 self-replacing Merino ewes (light shading) and supplied by pasture (dark shading) consisting of (a) 400 ha of good native pasture or, (b) 200 ha of good native pasture, 50 ha of native pasture+subterranean clover, 50 ha of lucerne, 50 ha of forage oats and 50 ha of tropical perennial grasses.


Comparison of methods for estimating herbage mass in small plotsG. M. Lodge and S. Harden


Abstract: Herbage mass (HM, kg dry matter (DM)/ha) of temperate perennial grasses was estimated using four methods: 1. whole plot estimates, 2. subplot (three strata) estimates, 3. BOTANAL estimates (10 per plot), and 4. cutting two quadrats in each of three strata per plot. Methods 1–3 were compared with Method 4 (6 cut quadrats) to identify the method that gave an accurate estimate of HM which could be achieved in a reasonable amount of time. Mean predicted sown species HM ranged from 0–694 kg DM/ha for Method 4 and from 0–1176 kg DM/ha for Method 3. Predicted HM was overestimated by Methods 1 and 2 at values <200 kg DM/ha and while at higher values it was underestimated by both these methods, the underestimates were lower for Method 2. Method 3 consistently overestimated predicted HM and had the highest value of sigma (the square-root of the estimated variance of the random error). The total time taken for pre- and post-processing and field sampling was highest for the destructive Method 4 (~26 hours) compared with 4–5 hours for Methods 1 and 2 and 7 hours for Method 3. Based on these data the best method of sampling for HM in small plots was to use an estimation technique in three strata per plot since its predicted values better covered the range, its estimated variance of random error was intermediate and it required less sampling time than Methods 3 and 4.

Key words: whole plots, stratif ication, BOTANAL, cut quadrats, sampling time, sigma, linear regression, correlation coefficient

IntroductionTechniques for estimating pasture herbage mass (HM, Hodgson 1979) and species composition have been comprehensively reviewed and documented by Brown (1954), Tothill (1978) and Mannetje (1978). Generally, these authors reported that the cutting of herbage material in quadrats and its sorting into species or functional group were suitable sampling techniques for comparative studies of species performance. However, quadrat cutting is destructive and may require high time and labour inputs (Mannetje and Haydock 1963). Hence non-destructive sampling techniques are often preferred, since regular close cutting of plant material may also have an effect on persistence (Mannetje 1978). Such techniques are also often less labour intensive, when compared with quadrat cutting as less material is collected and processed (e.g. bagging, sorting and weighing).

Both HM and species composition can vary temporally, as plant growth patterns vary with seasons, and spatially, as swards thin and weed species ingress, so assessment techniques need

to be sufficiently robust to reflect these changes. When sampling the HM and species composition of sown species in plots there are three main practical ways to reduce random sampling error; increasing the size of the sample; reducing the size of the sampling unit, or increasing the number of units using stratification (Jolly 1954). For small plots, increasing the size or number of samples may be impractical, but the use of stratification may be appropriate.

Visual estimation is a widely used non-destructive technique. It is usually applied in a double sampling technique in which HM/species composition is estimated in a large number of samples and then determined accurately in a few standard samples (Mannetje 1978). This method is the basis of the calibrated quadrat technique where actual and visual estimates for the same series of quadrats are used in regression to calculate estimates of HM/species composition. For HM, this method was described by Haydock and Shaw (1975) and has been commonly used in agronomic and grazing studies. For estimating species composition (as a percentage of total HM), BOTANAL procedures (Tothill et al. 1992) that combined a dry-weight rank method (Mannetje and Haydock 1963) with tied ranks (Tothill et al. 1992) and modifications


to multipliers for cumulative ranks (Jones and Hargreaves 1979) have also been widely used in grazing studies. Basically, the dry-weight rank method proposed three multipliers with proportional values of 0.702, 0.212 and 0.087 for species ranked 1, 2 and 3, respectively (Mannetje and Haydock 1963). Tothill et al. (1992) also described situations where the use of direct estimates of percent species composition was preferable to using the dry-weight rank method.

This paper reports a study that tested the hypothesis that estimates of pasture HM from different assessment methods in small plots would have different mean values, estimates of error and sampling times. This information was then used to identify the most appropriate method that provided accurate HM estimation with efficient use of time.

MethodsThe site and experimental plots used in this study were previously described in detail by Boschma et al. (2009). Briefly, the experimental site was located 12 km west of Manilla, New South Wales (30.74oS 150.61oE; elevation 400 m). Forty eight plots (6.0 by 1.35 m) were sown in May 2003 in a spatially adjusted randomised complete block design, with three replicates being used in the current study. Sixteen cultivars/lines of the temperate perennial grasses phalaris (Phalaris aquatica) and tall fescue (Festuca arundinacea syn., Lolium arundinaceum) were sown and regularly defoliated or grazed until October 2005. After that time plots remained undefoliated until they were mown in late May 2006. The current study was undertaken on four consecutive days (15–18 August 2006) when all sown grasses were vegetative.

There were four methods of assessment: Method 1, visual HM estimates of the whole plot; Method 2, visual HM estimates in three subplots (strata) of equal area per plot; Method 3, visual estimates using BOTANAL procedures and, Method 4, cut quadrats. For the first three methods, two experienced assessors were used. Whole plot (Method 1) and subplot estimates (Method 2) were undertaken on day 1 of the study, BOTANAL estimates (Method 3) on day 2

and the quadrats were cut (Method 4) on days 3 and 4. For the whole plot method, each assessor estimated total HM (scores 0–5, (0 = nil, 5 = high, in graduations of 0.1) and overall percentage of sown species. For the subplot method, total HM score and percent sown species was estimated for each stratum. These estimation methods were analogous to the type 3 procedure outlined by Haydock and Shaw (1975) for calibrating a standard yield scale. For the BOTANAL method, HM scores were estimated in 10 quadrats (0.4 by 0.4 m) along the centre line of each plot and dry-weight rankings assessed for five species categories (sown species, annual summer grass, annual winter grass, broadleaf weed and other perennial grass) using the methods described above. For the cut quadrat method, sown species and other herbage were harvested separately in two randomly located quadrats (0.4 by 0.4 m) in each of the three strata. Plant material was cut to a height of ~10 mm above ground level and dried at 80oC for 48 hours before weighing.

For methods 1−3, twenty calibration quadrats (0.4 by 0.4 m) were independently scored by each assessor. Calibration quadrats covered the range of HM and species composition. Species composition estimates and dry-weight rankings were done at separate times to maintain their independence. Calibration quadrats were then harvested, sorted into sown and other species and each portion dried as described above. Scores and percentage estimates were regressed (linear or quadratic R2>0.80) against actual HM (kg dry matter (DM)/ha) and percentage of sown species to determine the HM of sown species. For Method 3, the 10 estimates of total HM and dry-weight ranks in each plot were used to obtain mean HM for the sown and other species.

Herbage mass estimates determined by Methods 1–3 were compared with Method 4 (cut quadrats) using linear regression analyses. Sigma (the square-root of the estimated variance of the random error) measures the scatter about the regression line and the correlation coefficient (r, the square-root of the multiple R2 value) indicates the strength of the linear relationship. Visual inspection of graphical plots (not presented) indicated whether or not there


was over or underestimation. For each method, the times taken for different operations such as pre-field preparation (e.g. bag numbering), field sampling (e.g. scoring and/or cutting quadrats) and post-field handling (e.g. sorting, processing, weighing, data entry and calculation) were also noted and expressed as the number of hours and minutes/person and the total time taken.

Results and discussionMean total and sown species HM for Method 4 (cut quadrats) was 872 and 259 kg DM/ha, respectively and predicted sown species HM values ranged from 0–694 kg DM/ha. Method 1 had the lowest sigma value (Table 1) indicating the least variation when compared with the cut quadrats, but predicted values were in a much narrower range (113–559 kg DM/ha, with only one value being >400 kg DM/ha) than those for the other methods. Both Methods 1 and 2 overestimated predicted HM at values <200

kg DM/ha. At >200 kg DM/ha both methods underestimated predicted HM, although the underestimates were much lower for Method 2. Method 3 consistently overestimated sown species predicted HM (range 0–1176 kg DM/ha) and had the highest value of sigma (Table 1). Overestimation for Method 3 (BOTANAL) was probably associated with a lack of proportional values between 0.333 and 0.702 and the occurrence of species dominance, with about one-third of all proportional values for the sown species being ≥0.702. The lack of mid-range proportional values may have been overcome by using direct estimates of percent species composition (Tothill et al. 1992). With a plot length of 6 m some difficulty also occurred for Method 3 in selecting the required minimum of 10 independent quadrats and so it may not be suitable for some small plots.

In this study, Method 4 was the most labour and time intensive, taking an estimated total time of 25 h and 45 min (12 h/person) for pre- and post-processing and field sampling (Table 2). In comparison, Methods 1 and 2 required a total sampling time of 4–5 h (2 h 45 min and 3 h/person, respectively) and Method 3 was intermediate, requiring 7 h total time (4 h 45 min/person, Table 2).

Table 1. Values of sigma (square-root of the estimated variance of the random error) and r (correlation coefficient) for Method 4 (cut quadrats) compared with Methods 1-3.

Method Sigma r

Method 1 – whole plot 61.3 0.74

Method 2 – subplot 107.3 0.67

Method 3 – BOTANAL 156.2 0.78

Table 2. Comparative time [hours (h) and minutes (min)] and number of persons required for each of the four sampling methods for field sampling and pre- and post-field processing, together with the total time taken and total time per person.

Method 1 (whole plot)

Method 2 (subplot)

Method 3 (BOTANAL)

Method 4 (cut quadrats)

Pre-field

No. of persons 1 1 1 1

Total time 15 min. 15 min. 15 min. 3 h

Field


Total time 3 h 3 h 30 min. 5 h 30 min. 14 h 15 min.

Post-field


Total time 1 h 1 h 1h 15 min. 8 h 30 min.

Total time taken

Total time 4 h 15 min. 4 h 45 min. 7 h 25 h 45 min.

Total time/person 2 h 45 min. 3 h 4 h 15 min. 12 h


Selection of the most appropriate sampling method involves the estimates satisfactorily covering the known range of predicted values, having an acceptable variance of random error and comparatively short sampling times. In our study, Method 1 had the lowest sigma value and sampling time/person, but the predicted data occurred over a much narrower range than for those of the cut quadrats (113 to generally <400 kg DM/ha v. 0–694 kg DM/ha). Method 3 had the highest sigma value, markedly overestimated the predicted value (0–1176 kg DM/ha) and had sampling times per person that were 140–155% higher than Methods 1 and 2. Hence, in the current study Method 2 (HM estimates in three strata per plot) best met the above criteria.

AcknowledgmentsThese data were collected as part of the National Plant Evaluation Program within the CRC for Plant-based Management of Dryland Salinity, jointly funded by the Grains Research and Development Corporation and the Department of Primary Industries (formerly Industry & Investment NSW). We gratefully acknowledge the assistance of Brian Roworth, Suzanne Boschma, Mark Brennan and Ivan Stace in collecting the data and processing the herbage samples.

ReferencesBoschma SP, Lodge GM, Harden S (2009) Establishment

and persistence of perennial grass and herb cultivars and lines in a recharge area, North-West Slopes, New South Wales. Crop & Pasture Science 60, 753–767.

Brown D (1954) ‘Methods of surveying and measuring vegetation’. Bulletin No. 42, Commonwealth Bureau of Pastures and Field Crops. (Commonwealth Agricultural Bureaux: Farnham Royal)

Haydock KP, Shaw NH (1975) The comparative yield method for estimating dry matter yield of pasture. Australian Journal of Experimental Agriculture and Animal Husbandry 15, 663–670.

Hodgson J (1979) Nomenclature and definitions in grazing studies. Forage Science 8, 1–8.

Jolly GM (1954) Theory of Sampling. Chapter 2 In ‘Methods of surveying and measuring vegetation’. Bulletin No. 42, Commonwealth Bureau of Pastures and Field Crops. pp. 8–18. (Commonwealth Agricultural Bureaux: Farnham Royal)

Jones RM, Hargreaves JGN (1979) Improvements to the dry-weight-rank method for measuring botanical composition. Grass and Forage Science 34, 181–189.

Mannetje L t’ (1978) Measuring Quantity of Grassland Vegetation. Chapter 4 In ‘Measurement of Grassland Vegetation and Animal Production’. Bulletin No. 52, Commonwealth Bureau of Pastures and Field Crops. pp. 63–95. (Commonwealth Agricultural Bureaux: Farnham Royal)

Mannetje L t’, Haydock, KP (1963) The dry-weight-rank method for the botanical analysis of pasture. Journal of the British Grassland Society 18, 268–275.

Tothill JC (1978) Measuring Botanical Composition of Grasslands. Chapter 3 In ‘Measurement of Grassland Vegetation and Animal Production’. Bulletin No. 52, Commonwealth Bureau of Pastures and Field Crops. pp. 22–62. (Commonwealth Agricultural Bureaux: Farnham Royal)

Tothill JC, Hargreaves JNG, Jones, RM, McDonald CK (1992) BOTANAL – a comprehensive sampling and computing procedure for estimating pasture yield and composition. I. Field sampling. CSIRO Australia, Division of Tropical Crops and Pastures. Tropical Agronomy Technical Memorandum No. 78.


Using height and density to estimate the herbage mass of different pastures in northern New South Wales

G.M. Lodge, M.A. Brennan, P.T. Sanson, B.R. Roworth and I.J. Stace


Abstract: The MLA Pasture Ruler for estimating pasture herbage mass was developed for a moderately dense pasture up to 14 cm high. In this paper, regression equations (r-value >0.78) between herbage mass and a herbage index (height x density) were developed for four pasture types with different structures and growth (native perennial grass pasture, lucerne, forage oats and tropical perennial grass) in northern New South Wales. Using this approach estimates can made for a wider range of pasture heights and densities than those that apply to the Pasture Ruler. By simply estimating pasture height and density the derived equations can be easily used to accurately assess pasture herbage mass.

Key words: pasture herbage mass, herbage index, native pastures, lucerne, tropical perennial grasses, forage oats

IntroductionThere is an urgent need for simple, easy-to-use tools that can assist producers to objectively assess pasture quantity (e.g. Lodge et al. 2011) and so make timely decision about adjusting stocking rates and matching on-farm forage resources to livestock feed requirements. One such tool that is widely available is the MLA Pasture Ruler (MLA 2004), which provides a scaled conversion of pasture height to pasture quantity for a ‘moderately dense’ (75% density) pasture. However, the maximum height of pasture for which the MLA Pasture Ruler can be used is only 14 centimetres (cm). In reality, many pastures on-farm are also of less than moderate density as a result of the interaction of sub-optimal grazing and/or fertiliser application with variable climates over the past few years (e.g. Lodge and McCormick 2010). Also, many pastures, such as those dominated by tussocky native perennial grass or upright tropical perennial grasses or grazed lucerne (Medicago sativa), have an inherently high amount of bare ground between plant crowns. This low plant density, combined with plants that are often more than 50 cm high, means that there are many situations in which the conversion factors used for the MLA Pasture Ruler are not applicable.

These situations regularly occur in northern New South Wales (NSW) where there are a range of

forage options, such as C3 and C4 native perennial grasses, lucerne, summer-growing tropical perennial grasses and winter-growing forage oats (Avena sativa). The herbage mass (HM, kg dry matter (DM)/ha) of all of these potential forage sources needs to be assessed on-farm. As part of the EverGraze project in northern NSW (Lodge et al. 2008), estimates of HM were derived from plant height and pasture density relationships and compared with theoretical values obtained from the MLA Pasture Ruler. Similar principles to those used for the Pasture Ruler were applied to derive simple multipliers that gave more reliable and realistic estimates for a wide range of pasture types.

MethodsAs part of an on-farm livestock and pasture monitoring project in northern NSW (Lodge et al. 2011), data were collected for plant height (cm) and density (%), plant HM and residual HM (the quantity of herbage <1 cm in height) from 2007 to 2010 for each of the four different pasture types above. Values for plant height (assessed as the height (cm) of the bulk of the vegetative plant material) and plant density [expressed as a % from 0 (low) to 100 (high)] were multiplied together to give a herbage index (HI, height x density). Herbage mass values for the different pasture types were determined over a range of seasons and growing conditions. All assessments were in quadrats (40 by 40 cm) and HM was estimated by cutting plant material to a height of 1 cm above ground level. Residual


herbage mass (0−1 cm) was estimated from 50-mm diameter cores taken from the cut area, with the herbage washed to remove any soil particles. All harvested material was dried at 800C for 48 hours before weighing. Linear regression equations for the MLA Pasture Ruler were back calculated using height values of 0−14 cm and a pasture density of 75% for each of the height values on the MLA Pasture Ruler.

For each pasture type, linear regression was applied to the values for actual HM (Y) and HI (X) and the significance (P < 0.05) of the relationship was assessed using the correlation coefficient (r-value). Values of R2 were used to describe the proportion of the variation in Y that was attributed to its linear regression on X. These regression analyses were applied to two situations. The first was where the pasture height was ≤10 cm for all pasture types, except tropical perennial grasses (pasture height ≤20 cm), where y = aX (equation 1) was used, since as HM approaches zero it is more appropriate to fit the data through the origin. The second situation was where pasture height was higher than these values and Y = aX + b (equation 2) was applied. Given that the relationship between height and herbage mass on the MLA Pasture Ruler is not strictly linear the corresponding values for a 5 cm high, 75% density pasture calculated for equations 1 and 2 were 1238 and 1143 kg DM/ha, respectively compared with 1400 kg DM/ha for a height of 5 cm on the Pasture Ruler. For each pasture type sampled, the data shown in Table 1 indicate the mean and range of values and the number of samples used in the analyses.

Results and discussionFor the four pasture types studied, mean pasture height (Table 1) ranged from 17.8 (lucerne) to 29.4 cm (tropical perennial grass) and maximum pasture height was >49 cm. Mean density was ~35% for native pasture and forage oats and ~15% for lucerne and tropical perennial grass, but ranged from 0−100% (Table 1). Actual mean HM was <1800 kg DM/ha for native pasture and lucerne and >3200 kg DM/ha for forage oats and tropical perennial grasses (Table 1), ranging up to 11,600 kg DM/ha for the latter.

Estimates of residual HM were ~250 kg DM/ha for lucerne and forage oats and >1000 kg DM/ha for native pasture and tropical grasses (Table 1), highlighting the importance of cutting height on HM estimation of different pasture types.

The linear regression equations given in Table 2 were all significant (P < 0.05) and as shown by the R2-value more than 61% of the variation in estimated HM was accounted for by its linear regression on the herbage index (HI). The advantage of using the equations for the four pasture types (Table 2) is that they apply to all pasture heights and densities, whereas the MLA Pasture Ruler regressions apply only to pasture heights of 1−14 cm and a density of 75%. Sufficient variation was also apparent in both the slope and intercept values in Table 2 to justify using different linear regression values for different pasture types and heights.

Use of the equations in Table 2 is best shown by two examples. In the first example, to estimate the HM of a native pasture with a height of 10 cm and a density of 20%, use equation 1 in Table 2 since pasture height is ≤10 cm. Using this equation the HM estimate would be 3.23 x (10 x 20) = 646 kg DM/ha. In the second example, the native pasture has a height of 50 cm and a density of 30%, so equation 2 in Table 2 is used since pasture height is >10 cm. Using this equation the HM estimate would be 2 x (50 x 30) + 692 = 3692 kg DM/ha. In practice, since only estimates of pasture quantity are required, the calculated values could be rounded to the nearest 50 or 100 kg DM/ha.

Finally, the HM estimates that would be obtained using equations 1 and 2 for the MLA Pasture Ruler and the four pasture types were compared at a pasture density of 75% (Table 3). Using equation 1 for pastures ≤10 cm high, for a pasture height of 5 cm the MLA Pasture Ruler approximated the value calculated for the native pasture (1143 v. 1211 kg DM/ha), but markedly under estimated the HM of the other pasture types by 600−2000 kg DM/ha (Table 3). Applying equation 2 to a 5 cm high pasture the MLA Pasture Ruler HM estimate approximated the value for lucerne (1270 vs. 1263 kg DM/ha), under estimated the value for native pasture


Table 1. Mean pasture height (cm), density (%) and actual herbage mass (kg DM/ha) with the range in measured values given in parentheses for four different pasture types. Mean values are also presented for the residual herbage mass (kg DM/ha) and n indicates the number of samples used to calculate the mean.

Pasture type Height (cm)

Density (%)

Herbage mass (kg DM/ha)A

n Residual herbage mass (kg DM/ha)B

n

Native pasture 18.3 (0−74) 33 (1−100) 1770 (0−8590) 1160 1300 427

Lucerne 17.8 (0−60) 16 (0−60) 1110 (0−4795) 408 245 89

Forage oats 21.3 (2−49) 35 (4−67) 3220 (160−8085) 75 255 25

Tropical perennial grass 29.4 (0−58) 15 (0−55) 3230 (0−11600) 55 1010 20AAbove ground herbage mass >1 cm above ground level for all pasture types. BAbove ground herbage mass from ground level to a height of 1 cm.

Table 2. Linear regression equations and R2-values for the MLA Pasture Ruler and four different pasture types for equation 1 (pasture heights ≤10 cm for all pasture types, except tropical perennial grasses which were ≤20 cm) and equation 2 (all pasture heights).

Method/pasture type Equation 1 Equation 2

MLA Pasture RulerA HM = 3.05HI R2 = 0.94 HM = 2.62HI + 287 R2 = 0.98

Native pasture HM = 3.23HI R2 = 0.66 HM = 2.00HI + 692 R2 = 0.70

Lucerne HM = 5.44HI R2 = 0.75 HM = 2.01HI + 509 R2 = 0.73

Forage oats HM = 8.33HI R2 = 0.62 HM = 2.23HI + 1388 R2 = 0.62

Tropical perennial grass HM = 8.76HI R2 = 0.75 HM = 5.05HI + 947 R2 = 0.86AAssumes a pasture density of 75% (moderately dense) with pasture heights ranging from 0−14 cm.

Table 3. Estimated herbage mass (kg DM/ha) for the MLA Pasture Ruler and four different pasture types using equation 1 for a pasture height of 5 cm and equation 2 for pasture heights of 5 and 20 cm. For all calculations a pasture density of 75% was used.

Method/pasture type

Pasture height (cm)

5 5 20

Equation 1 Equation 2

kg DM/ha

MLA Pasture Ruler 1143 1270 4217

Native pasture 1211 1442 3692

Lucerne 2040 1263 3524

Forage oats 3124 2224 4733

Tropical perennial grass 3285 2841 8522

(1270 vs. 1442 kg DM/ha) and markedly under estimated the HM values for forage oats and tropical grass by >1000 kg DM/ha (Table 3). When applying equation 2 to a 20 cm high pasture the MLA Pasture Ruler over estimated the HM of native pasture and lucerne (4217 vs. 3692 and 3524 kg DM/ha, respectively) and under estimated forage oats HM and tropical

perennial grass HM by ~500 and ~4300 kg DM/ha, respectively.

Obviously, in the present study the use of a herbage index for different pasture types has only been considered in the context of estimating total HM. For animal production, green HM is of primary interest and to estimate this, the total HM estimates would need to be adjusted for the proportion of green material. When estimating percent green it is important to remember that the estimate is on a dry-weight basis and adjustments for green material with water contents of up to 80% of dry-weight and dead material with as low as 10% moisture will need to be made.

Using the equations specifically derived for the four different pasture types in this study had the advantage of being able to estimate HM for pastures of any height and density and to take into account the modifying effect of pastures with different structures and growth habits (e.g. upright vs. prostrate and bunched vs. non-bunched grasses).


AcknowledgmentsEverGraze is a Future Farm Industries CRC, Meat & Livestock Australia and Australian Wool Innovation research and delivery partnership. The Department of Primary Industries (formerly Industry & Investment NSW) is a core partner of the Future Farm Industries CRC. We gratefully acknowledge the assistance of the cooperating landholders in the EverGraze northern NSW project.

ReferencesLodge GM, Boschma SP, Brennan MA (2008) EverGraze

research in northern New South Wales. In ‘Proceedings of the 23rd Annual Conference of the Grassland Society of NSW’. (Eds SP Boschma, LM Serafin, JF Ayres). pp. 133−134. (NSW Grassland Society Inc.: Orange)


Lodge GM, Brennan MA, Sanson P, Roworth BR, Stace I (2011) On-farm monitoring of sheep and pasture production in the EverGraze northern New South Wales project. In ‘Proceedings of the 26th annual conference of the Grassland Society of NSW.’ (Eds G Lodge, J Scott, W Wheatley). pp. 112 (Grassland Society of NSW Inc.: Orange).

MLA (2004) Improving pasture use with the MLA Pasture Ruler. Tips & Tools. (MLA; Sydney). Also available at:

http://www.mla.com.au/CustomControls/ PaymentGateway/ViewFile.aspx?1DzSU1GMe3Iahr LvRs6NX/izeZ+FqtK8xrBWP9Y6/RMfzdQfJppzWoK 4aEqDgBin3EYMKKAfsht7d1Tnt3BqiA==

FREECALL: 1800 00 SEEDVISIT US ON www.heritageseeds.com.au

Southern New South Wales Regional Business Manager Phil Williams > mobile: 0427 010 759> Email: [email protected]

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“Trevenna” sheep production demonstration site of methane emissions on the northern Tablelands of NSW

C. EdwardsA, M.J. McPheeB, J. MeckiffA, N. BallieC, D. SchneiderC and R. HegartyC

ADepartment of Primary industries, Ring Rd Armidale 2351. BDepartment of Primary Industries, Trevenna Rd, Armidale 2351.

CUniversity of New England, Armidale, 2351; [email protected]

Abstract: A demonstration site investigating two production systems for crossbred lambs is currently being evaluated for methane emissions at “Trevenna” Armidale, NSW. The site will give producers and researchers a practical insight into the carbon cycle, in particular methane. The replicated study over two years compares animal productivity and emissions from a low fertility and low stocking rate (hills) with a high fertility and higher stocking rate (flats) treatment. Initial set up characterised the two sites and allowed for equivalent areas to be subdivided. Extensive measurements of the pastures and livestock are being made. Other measurements being recorded, include soil water, nitrous oxide and weather data. Analysis of the systems will be investigated using four decision support tools. The site will also enhance knowledge of methane dynamics in terms of farm carbon and productivity to northern Tablelands producers and researchers.

Key words: on-farm emissions, life cycle measurements, whole-farm system models, mitigation

Introduction A 36 ha demonstration site based at the University of New England’s “Trevenna” property, on the northern Tablelands of New South Wales (NSW, 30o 28’57.28”S; 151o38’2.47”E) has been established. It is one of four national sites across Australia that has been established in collaboration with Meat & Livestock Australia and the Australian Government’s Climate Change Research Program to demonstrate potential mitigation strategies for enteric greenhouse gas emissions from ruminants. It is a joint project between the Department of Primary Industries and the University of New England.

The “Trevenna” project will equip northern Tablelands producers and researchers with knowledge and tools for understanding on-farm sheep production and methane emissions. It will demonstrate the lifecycle of greenhouse gas emissions in sheep grazing enterprises, contrast two sheep grazing systems in different landscapes, and show different methods of predicting and measuring on-farm methane production. Decision support tools will also be used to estimate methane emissions from the site. The site will also be a training facility

for undergraduate and postgraduate students learning about on-farm emissions, life cycle measurements and whole-farm system models.

MethodsThe “Trevenna” demonstration site has a summer dominant rainfall and varies in elevation from 1068 to 1022 m asl. The site has two different landscapes: hills and flats. The hill country is dominated by summer-growing native species, interspersed with yearlong green native grasses and naturalised cool-season introduced species. The flats are dominated by perennial introduced species with a large percentage of legumes.

An initial EM38 survey and soil samples stratified the landscapes and paddocks for the demonstration. Additional subdivision occurred to block each landscape into three classes and three paddocks within each class. Botanical composition will be examined each season within the two landscapes. Fertiliser has been applied at a rate of 20 kg/ha of phosphorus, 25 kg/ha of sulfur and 70 kg/ha of nitrogen to the flats that has assisted in delineating the differences between the two landscapes.

Stocking densities were determined using PRO PlusTM (McPhee et al. 2000). Fodder budgets indicated a stocking rate of 3.7 dry sheep equivalents (DSE)/ha on the hills and 6.7 DSE/



ha on the flats. Merino ewes were sourced from the UNE Merino research flock and were joined to Border Leicester rams in April 2010. Allocation of the pregnant ewes was randomised and lambing occurred in September 2010.

Monthly pasture (green herbage mass, legume percentage and quality) are recorded and regular animal production data (liveweight, condition score, fecundity, wool and carcass weights at slaughter) are being collected. In addition, pasture scans of the paddocks are made by the Crop Circle (Holland Scientific equipment model ACS210) to determine its correlation with measured herbage mass each month. Water holding capacity and nitrous oxide measurements are also being recorded from the site. The design of the demonstration site, including the replication, animals and pasture measurements have been described by McPhee et al. (2010).

Results and discussionData collected will be important in our understanding of whole-farm sheep production systems on the northern Tablelands of NSW. Information will be used in models such as AusFarm and EcoMod, and inventory models such as FarmGas and OVERSEER. At the end of the second year (2012), a detailed analysis will examine the differences between the two landscapes. A lifecycle analysis and economic study will also be conducted at the conclusion of the project.

On ground demonstration sites, such as “Trevenna”, are important for improving producers’ and researchers’ knowledge concerning methane emissions. Such sites will enable better decisions on methane mitigation options and will help inform advisors and policy makers. It will also increase the understanding, awareness and adoption regarding methane emissions in farm carbon. The validation of farm system models will be valuable for assessing the whole-farm system consequences and enable the testing of a broader range of mitigation options in the context of the northern Tablelands environment.

AcknowledgmentsThe authors gratefully acknowledge the funding supported by Meat & Livestock Australia and the Australian Government’s Climate Change Research Program. Assistance from students of the University of New England is also acknowledged along with the support from University of New England staff.

ReferencesMcPhee MJ, Bell AK, Griffith GR, Graham P, Meaker GP

(2000) PRO Plus: a whole-farm fodder budgeting decision support system, Australian Journal of Experimental Agriculture 40, 621−630.

McPhee MJ, Edwards C, Meckiff J, Ballie N, Schneider D, Arnott P, Cowie A, Savage D, Lamb D, Guppy C, McCorkell B, Hegarty R (2010) Estimating on-farm methane emissions for sheep production on the Northern Tablelands: establishment of demonstration site. AFBM Journal 7, 85−94.

EverGraze is a Future Farm Industries CRC, Meat and Livestock Australia and Australian Wool Innovation research and delivery partnership

For information on the application of EverGraze principles in research and on farm, go to www.evergraze.com.au

The EverGraze Principle The right perennial plant put in the right place for the right purpose with the right management can achieve simultaneous profit, risk and natural resource management benefits


Using near infrared reflectance spectroscopy (NIRS) to determine nutritive value of tropical perennial grasses

S.P. Boschma, S.A. Sissons and M.J. Sissons


Abstract: Near infrared reflectance spectroscopy was used to develop calibrations for nitrogen (N), dry organic matter digestibility (DOMD), acid detergent fibre (ADF) and neutral detergent fibre (NDF) for digit grass (Digitaria eriantha ssp. eriantha) cv. Premier and Rhodes grass (Chloris gayana) cv. Katambora. The coefficient of determination of calibrations developed for N and ADF were excellent, while the calibrations developed for DOMD and NDF were lower quality, but suitable for most applications. With additional sampling and calibration development these calibrations can be used to analyse plant samples from similar environments and could be broadened to other species and environments.

Key words: NIR

IntroductionNear infrared reflectance spectroscopy (NIRS) is an accurate, rapid and cost effective analytical technique that has been commonly used to determine many organic compounds in a wide range of products. Since NIRS was first identified as having potential to determine nutritive value constituents of forage in the 1970s (Norris et al. 1976), there have been many advances in the technology and calibration methods, and the technique is now an accepted method for determining nutritive value of forages and is extensively used throughout the world (e.g. Alomar et al. 2003; Shenk and Westerhaus 1994).

This paper describes the development of calibrations on an NIRS for nitrogen (N), dry organic matter digestibility (DOMD), acid detergent fibre (ADF) and neutral detergent fibre (NDF) for two tropical perennial grasses. The calibrations will be used to determine these four nutritive value constituents on tropical perennial grass samples collected from an experiment near Tamworth, New South Wales (NSW).

Materials and methodsField experimentA study was conducted on a red chromosol soil (Isbell 1996) near Tamworth, NSW (31o16’S, 150o52’E, 490 m). The experiment was a split-plot design with three replicates. Main-plots were defoliation frequency; defoliated every 2 and 6 weeks (to a height of 50 mm using a rotary

mower fitted with a catcher), with three forage species and five N rates randomised within each defoliation treatment. Forage species consisted of two perennial grasses; digit grass (Digitaria eriantha ssp. eriantha) cv. Premier and Rhodes grass (Chloris gayana) cv. Katambora sown in December 2005, and forage sorghum (Sorghum bicolor ssp. bicolor x S. bicolor ssp. drummondii hybrid) cv. Sweet Jumbo, which was sown in spring each year. Nitrogen treatments were applied at rates of 0, 50, 100, 150 and 300 kg N/ha as Easy N® (425 g N/L). Nitrogen was applied as 50 kg N/ha every 6 weeks (after defoliation), except for the 300 kg N/ha rate which was applied in three applications of 100 kg/ha. Defoliation treatments were from spring−autumn when the tropical grasses were actively growing for two seasons; 2006–07 and 2007–08. Nitrogen applications commenced with the first defoliation in spring of each season. Over the experimental period herbage mass and plant frequency were assessed and samples collected for analyses of soil N and forage nutritive value.

Sample collection for nutritive value analysesImmediately prior to the application of each 6-week defoliation treatment, forage samples (0.4 x 0.4 m quadrat) were taken from digit grass and Rhodes grass plots fertilised with 0, 100 and 300 kg N/ha in both defoliation treatments from replicates 1 and 2 (i.e. a total of 24 plots sampled at each assessment). Samples were cut to a height of ~50 mm above the soil surface and stored in paper bags. In the laboratory, each


sample was separated into four components; green and dead leaf, and green and dead stem (when present). These components were dried at 65oC for 48 h and ground to pass through a 1-mm sieve (Shenk and Westerhaus 1994). Plots were sampled five times in each growing season, giving a total of 146 and 175 samples in 2006−07 and 2007−08, respectively.

Additional tropical grass samples were collected from an adjacent experiment to give a broader range in nutritive value for NIRS calibration development. These samples were collected and processed using the method described above.

Chemical analyses of reference samplesAll samples collected in the 2006−07 season, additional tropical grass samples from an adjacent experiment and 60 samples from the 2007−08 season were analysed (Anon. 2009) for N (Australian Fodder Industry Association (AFIA) method 1.5R), DOMD (AFIA method 1.7R), ADF [AFIA method 1.8A(a)] and NDF [AFIA method 1.9A(a)].

NIRS calibration developmentSpectra for all samples were measured using a NIRSystems Model 6500 spectrophotometer (Foss NIRSystems Inc., Laurel, MD, USA) in reflectance mode using a quarter-full small sample cell. All spectra were recorded for the 408−2492 nm range and saved as the average of 32 scans per sample, however the colour range (408−807 nm) was not used in calibration development. Data analyses were performed using WinISI software (Foss NIRSystems Inc., Laurel, MD, USA).

Results and discussionIdentification of appropriate mathematical treatmentsAll spectra from samples collected in the 2006−07 season and the additional samples were inspected and outliers removed from the data set. A subset of 55 samples, representing the range in each constituent was selected as a preliminary validation set, leaving the remaining 92 samples for preliminary calibration development. For each of the four nutritive value constituents, the NIR spectra in the preliminary calibration sample set were initially transformed using the

mathematical treatment 2,6,4,1 with each of five scatter transformation options; standard normal variate (SNV) and detrend, SNV only, detrend only, standard multiplicative scatter correction (MSC) and weighed MSC. In the mathematical treatment, the first value is the order of the derivative, the second the segment gap in data points over which the derivative is calculated, and the third and fourth values are the number of data points used for smoothing (Williams 1987). Several regression methods were also tested and modified partial least squares (PLS) was found to be superior to PLS and principal components regression. The calibration developed using each mathematical treatment and scatter option adjustment was validated using the preliminary validation sample set to determine the optimum mathematical treatment. The treatment 2,6,4,1 with scatter option SNV and detrend provided the best predictions for N and ADF. Adjustment of the derivative and smoothing resulted in good predictions for NDF and DOMD, and DOMD also performed better with the detrend only scatter transformation option (Table 1).

Calibration developmentSamples from the preliminary calibration and validation sample sets were recombined and used to develop a calibration (n = 147) for each of the 4 nutritive value constituents using the optimum mathematical treatments (Table 1). Calibrations were then used to predict the four constituents from a validation sample set represented by 60 samples collected in the 2007-08 season. These samples were identified by the WinISI software based on their spectral diversity and covered the range in the calibration of each constituent. The statistics of the validation samples and regressions are also shown in Table 1. The coefficient of determination was high (r2

>0.85, Table 1) for each constituent, in particular N and ADF, indicating the suitability of the calibrations for many applications (Osborne et al. 2002). The calibration for DOMD was the poorest and should not be used to replace chemical analysis, however it is suitable for screening purposes.

Our calibrations were similar to those reported by others. For example, Smith et al. (1998)


Table 1. NIRS mathematical treatment, calibration and validation sample and regression statistics, and statistics for combined sample calibrations for nitrogen (N, %), dry organic dry mater digestibility (DOMD, %), acid detergent fibre (ADF, %) and neutral detergent fibre (NDF, %)SNV, standard normal variate; SD, standard deviation; SEC, standard error of calibration; r2, coefficient of determination between NIRS and chemical values; SEP, standard error of prediction; Slope, slope of the regression between chemical and NIRS values; Bias, mean difference between chemical and NIRS values; SEP(C), standard error of prediction corrected for bias.

Statistics N (%) DOMD (%) ADF (%) NDF (%)

Mathematical treatment and scatter transformation

2,6,4,1, SNV and detrend

3,6,1,1 and detrend 2,6,4,1, SNV and detrend

3,6,1,1, SNV and detrend

Calibration sample and regression statistics

n 147 147 147 147

Mean 2.3 56.09 30.67 63.73

Minimum 0.2 43.0 16.0 27

Maximum 4.6 71.0 45.0 84

SD 1.02 5.15 4.67 6.58

SEC 0.10 1.85 0.92 1.61

r2 0.99 0.87 0.96 0.94

Validation sample and regression statistics

n 60 60 60 60

Mean 2.4 56.5 29.7 62.8

Minimum 0.8 44.0 22.0 52.0

Maximum 3.4 63.0 45.0 78.0

r2 0.95 0.80 0.94 0.83

SEP 0.12 2.09 1.09 2.01

Slope 0.98 1.02 1.07 0.99

Bias -0.02 -0.24 0.10 -0.15

SEP(C) 0.12 2.09 1.09 2.02

Combined regression statistics

n 207 207 207 207

SD 0.91 5.00 4.61 6.16

SEC 0.09 1.66 0.92 1.44

r2 0.99 0.89 0.96 0.95

reported better prediction statistics for dry matter digestibility of annual ryegrass (Lolium rigidum) (r2 = 0.93, standard error of prediction (SEP) = 3.4) than for N (r2 = 0.88, SEP = 1.3).

Prediction of nutritive value constituents for all samples To predict the four nutritive value constituents for all of the samples in the experiment described above, all samples from both the calibration and validation sample sets were combined and new calibrations developed using the optimum

mathematical treatments (Table 1). These calibrations (n = 207) had smaller standard deviations and standard errors of calibration to those developed using only samples from the 2006-07 season (n = 147) and would be best used to predict these nutritive value constituents on any future samples representative of the range included in the calibration sample set. Such calibrations should be validated by selecting ~1 in every 10 samples for chemical analysis that cover (or extend) the range of each constituent in the calibration. Inclusion of these samples and


any outside the current range would improve its robustness. The calibrations described in this paper were for only two species and so should be considered ‘species-specific’. Calibrations based on a range of species from different environments (i.e. ‘broad-based’ calibrations) have been found to give values with a similar degree of accuracy as species-specific calibrations, but to be effective broad-based calibrations need to include samples representing all possible sources of variation (Brown et al. 1990).

NIRS is an effective method to predict nutritive value of forages, including tropical perennial grasses. However, error is associate with all methods and in NIRS measurement it may result from a range of sources (Hruschka 1987), principally sampling error (e.g. homogeneity of the sample), reference error (i.e. variation between duplicate samples used for chemical analysis) and NIR method error (e.g. spectral measure error and poor choice of mathematical treatment). The development of robust calibrations relies on the inclusion of appropriate samples for calibration, using the best mathematical procedures to obtain the most accurate calibration and including samples that are representative of all possible sources of variation (Hruschka 1987).

ConclusionsOptimum mathematical treatments were identified for calibration of an NIRS for four nutritive value constituents (N, DOMD, ADF and NDF) for two tropical perennial grasses and used to develop a calibration to predict each constituent. The coefficient of determination of calibrations developed for N and ADF were excellent, while the calibrations developed for DOMD and NDF were lower but suitable for most applications. These calibrations will be used to predict the nutritive value of leaf and stem samples collected over two growing seasons in the current experiment.

AcknowledgmentsThis study was jointly funded by Future Farm Industries Cooperative Research Centre (CRC) (formerly the CRC for Plant-based Management of Dryland Salinity) and the Department of Primary Industries (formerly Industry & Investment NSW). We gratefully acknowledge the assistance of Peter Sanson, Brian Roworth, Ivan Stace, Mark Brennan and Ben Frazer in collecting and processing the samples. We also thank Incitec Pivot for providing the Easy N and Clive and Renee Barton for the use of their land.

ReferencesAlomar D, Fuchslocher R, de Pablo M (2003) Effect of

preparation method on composition and NIR spectra of forage samples. Animal Feed Science and Technology 107, 191−200.

Anon. (2009) ‘AFIA – Laboratory Methods Manual Edition 5’. Publication no. 03/001. (Australian Fodder Industry Association Inc.: Melbourne, Vic.)

Brown WF, Moore JE, Kenkle WE, Chambliss CG, Portier KM (1990) Forage testing using near infrared reflectance spectroscopy. Journal of Animal Science 68, 1416−1427.

Hruschka WR (1987) Data analysis: wavelength selection methods. In ‘Near-Infrared technology in the Agricultural and Food Industries’. (Eds PC Williams, KH Norris). pp. 35−55. (American Association of Cereal Chemists, Inc.: St. Paul, Minnesota, USA)

Isbell RF (1996) ‘The Australian soil classification.’ (CSIRO Publishing: Collingwood, Vic.)

Norris KH, Barnes RF, Moore JE, Shenk JS (1976) Predicting forage quality by infrared reflectance spectroscopy. Journal of Animal Science 43, 889−897.

Osborne B, Wesley I, Anderssen R (2002) NIR calibration guidelines. Project BRI 82 report prepared for Grains Research & Development Corporation.

Shenk JS, Westerhaus MO (1994) The application of near infrared reflectance spectroscopy (NIRS) to forage analysis. In ‘Forage quality, evaluation and utilization’ (Ed GC Fahey Jr.) pp. 406−449. (American Society of Agronomy, Inc., Crop Science Society of America, Inc. and Soil Science Society of America, Inc.: Madison Wisconsin, USA)

Smith KF, Simpson RJ, Armstrong RD (1998) Using near infrared reflectance spectroscopy to estimate the nutritive value of senescing annual ryegrass (Lolium rigidum): a comparison of calibration methods. Australian Journal of Experimental Agriculture 38, 45−54.

Williams PC (1987) Commercial near-infrared reflectance analysers. In ‘Near-Infrared Technology in the Agricultural and Food Industries’. (Eds P Williams, K Norris). pp. 35−55. (American Association of Cereal Chemists, Inc.: St Paul, Minnesota, USA)


Herbicides evaluated for tropical perennial grassesL.H. McCormick, S.P. Boschma, A.S. Cook and B.M. McCorkell

Department of Primary Industries, 4 Marsden Park Road, Calala NSW 2340; [email protected]

Abstract: Successful establishment of sown pastures is often threatened by weed competition in the seedling stage. While a range of herbicides are registered for weed control in grass-only pastures, many of these have not been evaluated on sown tropical perennial grasses and the range of summer growing weeds that compete with them at establishment. This paper reports the evaluation of 20 post-emergent herbicides and mixtures at Loomberah near Tamworth, and incorporates the results from earlier work undertaken at Narrabri. The data contributed to the successful application, by the Grassland Society of NSW, for a pesticide permit to use a broader range of herbicides for weed control on tropical perennial grasses. Producers now have greater flexibility for herbicide options to control a broader weed spectrum at pasture establishment.

Key words: secondary root system, pre-emergent, post-emergent, phytotoxicity, herbicide, weed control.

Introduction Initial herbicide studies in New South Wales (NSW) for weed control in tropical perennial grasses were conducted near Narrabri and commenced in 1998 (McMillan and Cook 1989, McMillan et al. 1992). These studies involved two pre-emergent and two post-emergent herbicide experiments investigating the effects of a broad range of generic herbicides. Although the work focused mainly on grasses such as Bambatsi panic (Panicum coloratum), purple pigeon grass (Setaria incrassata) and Curly Mitchell grass (Astrebla spp.), it was expected that the research would be applicable to other grasses such as Rhodes (Chloris gayana) and digit (Digitaria eriantha).

It was concluded from the pre-emergent herbicide studies that these herbicides were generally too damaging (high phototoxicity) to pasture grass species and resulted in highly variable weed control. Of those evaluated, metsulfuron and triasulfuron, were considered to be the options least likely to cause unacceptable damage to tropical perennial grasses, however they were registered for pre-emergent control of many grass weed species and the level of weed control obtained in the study was insufficient to risk potential damage to the grass pastures.

In contrast, the post-emergent herbicides produced lower and more consistent

phytotoxicity ratings and had acceptable weed control. However herbicides such a MCPA, 2,4-D amine and metsulfuron-methyl had the potential to cause moderate damage if applied to pasture grasses at growth stages less than 2–3-leaf stage. As the sown plants mature their level of tolerance increases rapidly such that applications of herbicides to pasture grasses at the early tillering stage often cause only slight and transient damage.

With the continued establishment of tropical perennial grasses across the North-West Slopes and Plains and now south into the Central-West Slopes and Plains, and east onto the northern Tablelands, knowledge on the effectiveness of a greater range of herbicides is required and their use registered to provide producers with greater flexibility for weed control.

The need for pre-emergent weed control can be managed mostly in the planning stage. Annual summer grass weeds are the biggest weed threat to establishing tropical perennial grass pastures and can be successfully controlled by preventing seed set for up to two years prior to establishing the tropical perennial grasses (Lodge et al. 2010). However there is an increasing need for more knowledge on post-emergent broadleaf weed control and registration of those herbicides suitable for tropical perennial grasses. This paper describes a study that evaluated a range of herbicides and lists the nine herbicides and mixtures that have approved use in NSW as a result of this and previous studies.


MethodsAn experimental site was selected at Loomberah, NSW in a newly sown commercial tropical grass pasture containing a mixture of Premier digit and Katambora Rhodes grass with a plant population ranging from 8–15 plants/m2. The soil was a red Chromosol with soil pH 5.6.

Sixteen herbicides were chosen and with mixtures of these herbicides there were 20 herbicide treatments and a control (nil treatment, Table 1). The experiment was a randomised complete block design with three replicates. Herbicide treatments were applied on 24 January 2008 to plots 3 x 5 m when pasture grasses were between the three-leaf and mid-tillering stages. Each herbicide was applied with a hand-held boom with LD 110-01 nozzles and water volume of 100 L/ha. Weather conditions were fine with temperature during application ranging 29−32ºC, humidity 47% and a light breeze (0.2−0.3 km/hr).

Weed population varied from 20–35 plants/m2 and the main weed species were pigweed (Portulaca oleracea) and caltrop or yellow vine (Tribulus terrestris). Other species in low numbers included Patterson’s curse (Echium plantagineum), turnip weed (Raphanus raphanistrum), deadnettle (Lamium amplexicaule), nightshade (Solanum nigrum), camel melon (Cucumis myriocarpus), paddy melon (Citrillus lanatus), cut-leaf mignonette (Reseda lutea) and tarvine (Boerhavia dominii).

Visual assessment of the pasture biomass reduction (%), and herbicide efficacy (%) compared with the control were conducted 15, 26 and 40 days after treatment (DAT). Pasture biomass (kg DM/ha) cuts (4 quadrats per plot, each 0.5 x 0.5 m, cut to 10 mm above ground level and dried for 48 h at 80oC) were also taken 40 DAT.

Results and DiscussionMost herbicides caused some phytotoxicity and pasture biomass reduction, compared to the control treatment. At 15 DAT 2,4-D amine 625 g/L + triclopyr 600 g/L, metsulfuron-methyl

600 g/kg + MCPA LVE 500 g/L, bentazone 480 g/L, clopyralid 300 g/L, fluroxypyr 200 g/L and metosulam 100 g/L resulted in over 20% reduction in tropical perennial grass biomass which exceeded the industry acceptable standard (Table 1). By 26 DAT, the tropical grasses had outgrown the herbicide damage with all treatments having less than 16% reduction in pasture biomass, with the exception of chlorsulfuron 750 g/kg which caused a 23% reduction in biomass (Table 1).

Only chlorsulfuron 750 g/kg continued to significantly reduce sown pasture biomass 40 DAT. Pasture biomass cuts at this time indicated that only clopyralid 300 g/L + florasulam 50 g/L+ MCPA LVE 500 g/L, aminopyralid 10 g/L+ fluroxypyr 140 g/L and chlorsulfuron 750 g/kg had resulted in a significant reduction in plant biomass compared with the control (P < 0.05, Table 1).

Eleven herbicides provided greater than or equal to 80% weed control by 15 DAT. Similarly, by 26 and 40 DAT, 11 treatments provided greater than or equal to 80% weed control. In contrast, dicamba 500 g/L, metsulfuron-methyl 600 g/kg, chlorsulfuron 750 g/kg, triclopyr 600 g/L, triclopyr 300 g/L + picloram 100 g/L + aminopyralid 8 g/L, metosulam 100 g/L, flumioxazin 500 g/kg and clopyralid 300 g/L only controlled up to 77% of weeds present.

Using these data, the Grassland Society of NSW applied for a minor use permit from the Australian Pesticides and Veterinary Medicines Authority (APVMA) for nine herbicides and mixtures. Eight are denoted in Table 1 by bold font and the ninth herbicide was triclopyr 300 g/L + picloram 100 g/L with an application rate of 2 L/ha identified from separate studies (A Cook, unpublished data). This permit (number PER12362 in force 3 February 2011–30 November 2015) allows those establishing tropical perennial grass pastures a wider choice of post-emergent herbicides and mixtures to target the different weed species experienced with summer establishment of pastures and can be obtained from www.apvma.gov.au/permits/search.php.


Table 1. Weed control (%) and reduction in sown pasture biomass (%) compared to the control 15, 26 and 40 days after treatment (DAT). Herbicides that can be used on tropical perennial grasses in NSW have bold text (permit number PER12362).

Treatments Rate product/ ha

15 DAT 26 DAT 40 DAT

Weed control (%)

Pasture biomass

reduction (%)

Weed control (%)

Pasture biomass

reduction (%)

Weed control (%)

Pasture biomass (kg

DM/ha

2,4-D amine 625 g/L 1.7 L 92 20 99 10 86 3072fluroxypyr 200 g/L 1.0 L 85 40 96 15 95 4357metsulfuron-methyl 600 g/kg + MCPA LVE 500 g/L

5 g + 0.5 L 93 29 96 9 96 3612

2,4-D amine 625 g/L + triclopyr 600 g/L

1.7 L + 0.3 L 81 28 90 3 88 3852

2,4-D amine 720 g/L 1.5 L 88 5 90 5 92 4108metsulfuron-methyl 600 g/kg + aminopyralid 10 g/L+ fluroxpyr 140 g/L1,

5 g + 0.75 L 79 10 88 2 85 4547

metsulfuron-methyl 600 g/kg + 2,4-D amine 720 g/L

5 g + 1.5 L 86 15 87 0 84 4393

MCPA amine 500 g/L 2.0 L 86 7 86 9 84 3635

aminopyralid 10 g/L + fluroxypyr 140 g/L

0.75 L 83 19 81 4 93 2463

chlorsulfuron 750 g/kg 10 g 78 18 81 23 71 1927clopyralid 300 g/L + florasulam 50 g/L

0.75 L 83 16 67 3 62 2638

clopyralid 300 g/L + florasulam 50 g/L+ MCPA LVE 500 g/L

0.75 L + 0.5 L

89 7 93 15 88 2658

dicamba 500 g/L 2.0 L 69 20 67 2 77 3518metosulam 100 g/L2 7 g 33 42 67 14 25 3815metsulfuron-methyl 600 g/kg 5 g 36 2 67 1 73 3744bentazone 480 g/L 2.0 L 83 30 62 12 90 3965triclopyr 600 g/L 0.5 L 40 11 50 10 51 3026triclopyr 300 g/L + picloram 100 g/L + aminopyralid 8 g/L

0.3 L 52 7 47 5 42 2722

flumioxazin 500 g/kg 60 g 29 17 16 7 19 4032clopyralid 300 g/L 0.3 L 7 31 9 13 7 2951Nil (control) –3 0 0 0 0 0 3844lsd (P = 0.05) 24.2 21.4 22.7 15.8 32 16841 Chem wet added to tank mix 2 Uptake added to tank mix 3 No rate applicable.

AcknowledgmentsThe authors wish to thank the Grassland Society of NSW Inc for applying to APVMA for a permit to use these herbicides and mixtures on tropical perennial grasses in NSW, A. and R. Whelan “Montarey”, Loomberah for providing the experimental site and P Moylan, S Squires and C Bowman, Department of Primary Industries (formerly Industry & Investment NSW), Tamworth for collecting the data.

ReferencesLodge GM, Brennan MA, Harden S (2010) Field studies

of the effects of pre-sowing weed control and time of sowing on tropical perennial grass establishment, North-West Slopes, New South Wales. Crop & Pasture Science 61, 182–191.

McMillan MG, Cook AS (1989) 1987–89 Results – Pastures. Weed Research and Demonstration Unit. (Department of Agriculture NSW: Glen Innes)

McMillan MG, Cook AS, Coldham JL (1992) 1989–92 Results – Pastures. Weed Research and Demonstration Unit. (NSW Agriculture: Glen Innes)


The value of ‘alternative’ nitrogen fertiliser products on pasture. 1. Pasture production at three sites

C.E. MuirA,D, N. GriffithsB and P. BealeC

ASwan Hill Chemicals Pty Ltd, 20 Nyah Rd, Swan Hill Vic. 3585; [email protected]. BDepartment of Primary Industries, Tocal Agricultural Centre, Paterson NSW 2421;

[email protected]. CDepartment of Primary Industries, Taree District Office, Taree NSW 2430;

[email protected]. DFormerly Department of Primary Industries, Berry District Office, Berry NSW 2535

Abstract: A series of experiments at Tocal, Taree and Berry on the NSW coast from winter 2009 to summer 2011compared the production of pastures topdressed with a range of coated urea products, alternative fertilisers and growth stimulants. Dry matter harvests were taken at a 3 to 8 week intervals depending on the growth rates of the dominant pasture type (kikuyu pasture from December to March and ryegrass pasture from June to November). Only treatments receiving at least 23 kg nitrogen (N)/ha from urea based products, significantly (P <0.05) increased pasture production over the control at every harvest. The greatest production responses were from urea products applied at 46 kg N/ha after each harvest at Berry and Tocal and 100 kg N/ha applied at every second harvest at Taree.

Key words: pasture, topdress, dairy, alternative fertiliser, poultry litter, Urea, Green Urea, Entec Urea, Twin N, Urea Supreme, Nutrisoil, ProGibb, Liquid Blood & Bone, dry matter

IntroductionSince 2007 increasing fertiliser costs have heightened farmer interest in ‘alternative’ fertiliser products aimed at reducing nitrogen (N) costs in pasture grazing systems. These include a range of biological sprays, compost extracts, fish emulsions, vermiculture liquids, hormonal granules, and composted mineral blends that may play a role alongside, or instead of, more ‘conventional’ products such as urea amendments and growth promotants

Urea applied at 30−50 kg N/ha/grazing, (150−500 kg N/ha/yr), is the most common form of N application for coastal pastures. Urea is subject to losses from volatilisation, nitrate leaching and denitrification that increase pasture production costs and pose an environmental threat. The magnitude of losses is highly dependent on the rate and method of application, soil characteristics, soil moisture and weather conditions at the time of application (Trenkle 2010; Watson et al. 2009). Therefore losses are episodic, varying between seasons and years.

The currently available amendments to reduce N losses have three modes of action; urease inhibition, nitrification inhibition and slowed release of N via fertiliser coating. Highest benefits are recorded in annual crops where N application rates of 100−200 kg N/ha are applied as a single application at establishment (Trenkle 2010; Watson et al. 2009). Authors differ in their assessment of these amendments in pastures where lower rates (30−50 kg N/ha/grazing) are made over multiple applications that more closely approximate plant demand. For example, though some authors document positive yield responses to urease inhibitors (Watson et al. 2009), others report marginal, uneconomic responses (Stafford et al. 2008).

This paper presents results of a series of replicated plot trials conducted on the NSW coast and discusses the relative merit of the various alternative and conventional products tested as potential sources of N for pasture production.

MethodsA series of three randomised block plot trials, (four replications) were established during 2009. The sites were highly fertile commercially managed pastures, on the NSW coastal zone. The pastures, located at Berry, Tocal and Taree, were





primarily composed of kikuyu (Pennisetum clandestinum) in the warmer months and oversown ryegrass (Lolium spp.) in the cooler months. Each trial comprised of between twelve and nineteen fertiliser treatments (including single or multiple untreated controls). Three sites were harvested using quadrates or lawn mower every three to eight weeks depending on the species, season and grazing rotation of the farm. Fertiliser was reapplied within 24−96 hours after each harvest.

Common treatments across all trials included, hand broadcast urea, and urea amendments: Green Urea™ a urease inhibitor, Entec Urea™ a nitrification inhibitor, and Urea Supreme™ a polymer coated urea. Progibb™ a gibberellic acid, Twin N™ a non-symbiotic N fixation product were applied by boomspray application. Four liquid fertiliser products Nutrisoil™ and Liquid Blood and Bone™, at Berry, and TNN liquids (15:5:5) and organic (NK) at Tocal, were also applied by boomspray. Data collection was completed by autumn 2011.

Results and discussionBerryRegardless of coating, concentrated granular urea products had the most significant (P <0.05) effect on increasing dry matter production (Figure 1). Urea products applied at 100 kg/ha after each harvest grew 80–86% more dry matter than the control, while treatments incorporating 50 kg/ha of urea products grew 51–57% more. Poultry litter only produced significant (P <0.05) yield increases within three months of application. ProGibb applied alone did not have significant (P >0.05) effects on dry matter production for either total dry matter over the trial nor at any individual harvest. When Progibb was applied to plots treated with urea it did not increase yield over urea applied alone (Figure 1). ProGibb is marketed to be used in winter in cooler environments so the relatively mild coastal climate may have negated the benefits of gibberellic acid that have been observed elsewhere (Mathew et al. 2009). All treatments without urea produced no significant (P >0.05) dry matter production responses when compared with the control (Figure 1).

Figure 1. Effect of topdressed fertiliser treatment on cumulative dry matter production on a dairy pasture at Berry, NSW. Hatched areas in November 2009 and February 2010 indicate missed harvests. Vertical bars above treatment symbols represent the l.s.d. (P = 0.05).


Table 1. Effect of topdressing treatment on the growth of kikuyu pasture at Taree, NSW in summer 2009−10. Those treatments not stated as ‘before’ (treatment applied two days prior to harvest) or ‘after’ (treatment applied after harvest), were topdressed after harvest. Treatments were applied at every second harvest.

Treatment Product rate

(kg/ha)

Nitrogen rate

(kg N/ha)

Total dry matter (5 harvests)

(kg DM/ha)

1 Control-1 0 0 2916

2 Control-2 0 0 3003

3 Urea, High (Before) 217 100 6523

4 Urea (After) 217 100 7258

5 Green Urea (Before) 217 100 7230

6 Green Urea (After) 217 100 6909

7 Entec Urea 217 100 6812

8 TNN Urea Supreme 217 100 6972

9 Urea, Low 109 50 5530

10 Twin N + Urea, Low 109 50 5076

11 Twin N + Poultry Manure 1667 50 4129

12 Poultry Manure 1667 50 4185

l.s.d. (P = 0.05) 706

The Nil/Urea 50 (alternate months) treatment produced the largest dry matter yield response per kilogram of applied N, achieving an extra 39.8 kg DM/kg N, followed by the Twin N/Urea 50 (alternate months) treatment at 32.2 kg DM/kg N. Considering the costs of application, the Nil/Urea 50 (alternate months) treatment produced the largest dry matter yield response per dollar of applied product, with each extra kg of DM costing 6.2 cents, followed by the Urea 50 treatment at 9.5 cents. The Twin N/Urea 50 (alternate months) was considerably more expensive at 14.5 cents for each extra kg DM. None of the non-urea fertiliser treatments produced a significant (P <0.05) yield response and hence were uneconomical.

TocalThe dry matter production response to granular urea was similar at this site to that at Berry (data not presented). At each harvest during the ryegrass phase in 2009 there was a significant (P <0.05) response when at least 50 kg/ha of urea was applied. Responses to urea in the 2010

ryegrass phase were also significant (P <0.05), but patchy establishment lead to greater variation in the results. During the kikuyu phase over summer 2009−10 the response was less obvious, but still significant (P <0.05), with longer harvest intervals and increased N mineralisation attributed to the smaller treatment differences.

TareeApplying at least 50 kg N/ha, regardless of the form, significantly (P <0.05) increased dry matter production of kikuyu (Table 1). However, there was significantly (P <0.05) lower response to poultry manure pellets supplying 50 kg N/ha compared with treatments containing urea at an equivalent N rate. This may indicate either lower N content in this batch of product than the bulk test, or a slower release of N from some fractions in the pelletised manure. Urea Supreme and Twin N + urea did not increase dry matter over that produced by urea alone with equivalent rates of N. Urea coatings and timing of application either before or after grazing had no additional effect on dry matter production (Table 1).


Ryegrass dr y matter product ion was significantly increased (P <0.05) by all forms of urea application (Table 2) regardless of the amendment coating or application rate used. The lack of a response between the ‘high’ and ’low’ urea rate indicates the high rate was above optimum for this site. Therefore any reduction in

N loss due to the amendments (applied only at the high rate) were not realised in the dry matter response. Gibberellic acid (ProGibb) and Twin N had no significant (P >0.05) effects on pasture production, consistent with results presented earlier in this paper.

Table 2. Effect of topdressing treatment on dry matter production of ryegrass at Taree, NSW in 2010. Treatments were applied after each harvest.

Treatment Product rate (kg/ha)

Nitrogen rate (kg N/ha)

Total dry matter (6 harvests) (kg DM/ha)

1 Control 0 0 5970 2 Urea, Low 109 50 10635 3 Urea, High 163 75 11540 4 Green Urea 163 75 11331 5 Entec Urea 163 75 10988 6 TNN Urea Supreme 163 75 11303 7 Black Urea 163 75 11378 8 Progibb 20g - 0 6373 9 Progibb 20g + Urea, Low 109 50 1044810 Progibb 20g + Urea, High 163 75 1139811 Twin N - 0 633112 Twin N + Urea, Low 109 50 10701

l.s.d. (P = 0.05) 963

ConclusionsOur results indicated no production benefit from using any of the range of alternative fertiliser products, growth promotants and soil amendments that we used on intensively managed, high fertility, coastal pastures. In contrast, urea-based products provided a consistent N rate related response in all trials. This suggested the non urea-based products were unable to meet the plant demand for N or produce some other growth stimulation effect.

Amendments to reduce losses from urea showed no production benefit at application rates of 23−100 kg N/ha/cut. This suggested that in these pasture systems the probability of N losses is low when applied after each grazing, at normal commercial rates.

AcknowledgmentsThis project was supported by funding from Dairy NSW. The technical expertise of Scott Richards and Michael Davy is greatly appreciated along with the biometrical analyses

of Terry Launders. Contributions from the range of private companies involved is gratefully acknowledged.

ReferencesMathew C, Hofmann WA, Osborne MA (2009) Pasture

response to gibberelins: a review and recommendations. New Zealand Journal of Agricultural Research 52, 213−225.

Stafford A, Catto W, Morton J (2008) Ballance agri-nutrients approach to sustainable fertiliser use. In ‘Proceedings: Carbon and nutrient management in agriculture’. (Eds Currie LD, Yates LJ). pp. 197−205. Occasional Report 21. (Fertilizer and Lime Research Centre, Massey University, Palmerston North, NZ)

Trenkel ME (2010) Slow- and controlled-release and stabilised fertilisers: an option for enhancing nutrient use efficiency in agriculture. Second Ed (IFA Paris, France). Available at: www.fertilizer.org.

Watson CJ, Laughlin R J, McGeough KL (2009) Modification of nitrogen fertilisers using inhibitors: opportunities and potentials for improving nitrogen use efficiency, IFS Proceedings 658,1−40.


The value of ‘alternative’ nitrogen fertiliser products on pasture. 2. Pasture quality and carryover effects at Tocal

C.E. MuirA,D, N. GriffithsB and P. BealeC

ASwan Hill Chemicals Pty Ltd, 20 Nyah Rd, Swan Hill Vic. 3585; [email protected]. BDepartment of Primary Industries, Tocal Agricultural Centre, Paterson NSW 2421.

[email protected]; CDepartment of Primary Industries, Taree District Office, Taree NSW 2430;

[email protected]. DFormerly Department of Primary Industries, Berry District Office, Berry NSW 2535

Abstract: At Tocal significant differences among treatments occurred in crude protein (CP), nitrate and water soluble carbohydrate as nitrogen (N) rate increased. The major effects occurred when urea or poultry litter was applied at the highest N rate (200 kg urea/ha/cut). At this rate the urease inhibitor increased leaf nitrates, indicating greater N retention in one harvest. Differences in CP and nitrate concentration were minor when N was applied at normal commercial rates and unaffected by urea amendments. Most quality parameters were within desirable levels regardless of the treatment and there were no commercially significant feed quality effects.

A carryover effect study, where treatments were applied once at the beginning of each season during the experiment with mown harvests simulating rotational grazing, indicated that the effects of high Nn applications (including poultry litter) were exhausted after about three months of pasture growth and removal.

Key words: pasture, topdress, dairy, alternative fertiliser, poultry litter, Urea, Green Urea, Entec Urea, Twin N, Urea Supreme, Nutrisoil, ProGibb, Liquid Blood & Bone, dry matter

IntroductionSince 2007 increasing fertiliser costs have heightened farmer interest in’alternative’ fertiliser products. These products are often claimed to improve pasture quality and may have a role in reducing nitrogen (N) costs in pasture grazing systems. Alternatives include a range of biological sprays, compost extracts, fish emulsions, vermiculture liquids, hormonal granules, and composted mineral blends.

Urea treated with polymer coatings or nitrification inhibitors has potential to reduce the luxury uptake of N through a slower release of N, or mineralisation of applied N (Trenkle 2010; Watson et al. 2009). A lower N and nitrate concentration in the forage can lead to a lower N concentration in urine and so lower N losses through volatilisation and leaching in urine patches

This paper reports on measurements of forage pasture quality, N and nitrate content sampled

from trials described by Muir et al. (2011) In addition, yield data from a carryover study tested claims of slower or sustained release of N from these products.

MethodsRandomised block plots, (four replications) were established at Tocal in 2009 on a highly ferti le commercial ly managed pasture, primarily composed of kikuyu (Pennisetum clandestinum) in the warmer months and oversown ryegrass (Lolium spp.) in the cooler months. The experiments had between twelve and nineteen fertiliser treatments (including single or multiple untreated controls) and metabolisable energy, crude protein, water soluble carbohydrates and nitrates were measured for the first harvest of ryegrass in 2009 and the third harvest in both the ryegrass and kikuyu seasons in 2009 and 2010 for all replications and treatments (Figure 1). Fertiliser was reapplied within 24−96 hours after each harvest.

Carryover effects of fertiliser treatments were also assessed by applying fertiliser only once at the beginning of each of four seasons, then





repeating harvests in the same sequence as described by Muir et al. (2011).

Results and discussionPasture quality Results at the first harvest in the ryegrass phase (August 2009) indicated that there were very highly significant (P <0.001) treatment effects for metabolisable energy, crude protein, water soluble carbohydrates and nitrates with the greatest effects at the high rates of urea (Figure 1). Brix measurements at two harvests found no significant treatment effects.

Amendments to urea did not reduce crude protein or nitrates at normal commercial rates. Urease inhibitors increased nitrates at the highest rate of urea indicating greater nitrogen retention. Apart from an extreme outlier in nitrates tested for the Green Urea 200 treatment (a possible urine patch sampling error in one replicate), feed quality for all treatments fell within the desirable range meeting the nutritional requirements of grazing animals. No

treatment provided a commercially significant nutritional advantage.

Carryover effectsAt each application and subsequent harvests there were highly significant (P <0.01) treatment effects with N rate where urea products and poultry litter. Though the effects were significant, the response to fertiliser diminished somewhat over time and by the third harvest there was far less variation between treatments than at the first harvest (Figure 2). This suggested that most of the fertiliser value of the treatments was exhausted around three months after application given normal pasture growth and removal patterns.

Urea amendments, growth promotants, alternative fertilisers and biological products provided no significant treatment effects in either the first or subsequent harvests. A similar result was found when treatments were applied every second harvest to kikuyu at Taree (Muir et al. 2011) Under these conditions these

Figure 1. Effect of fertiliser on (a) metabolisable energy, (b) crude protein, (c) water soluble carbohydrates, and (d) nitrates of a ryegrass pasture harvested in late August 2009 at Tocal, NSW, three weeks after treatment. All values are the mean of four replicates, except for nitrates recorded for Green Urea 200 (n = 3) and means predicted by a linear model. Analysis of variance for crude protein and water soluble carbohydrates was carried out on the square-root transformed percentages. Treatment means with the same letter are not significantly different (P = 0.05).


products showed no indication of sustained N release or N input over what was applied as urea or poultry litter.

ConclusionsAlternative fertiliser growth promotants and biological products had no commercially significant effects on pasture quality, N, or nitrate content in the three harvests sampled. Urea amendments showed neither a consistent production benefit, nor a reduction in the concentration of nitrogen or nitrate in annual ryegrass at normal application rates.

The carryover effect of single applications of N from 25 to 100 kg N/ha applied as urea or poultry litter was exhausted after about three months of pasture growth and removal. Neither urea amendments, growth promotants, nor alternative fertiliser products showed evidence of sustained release of N compared with normal urea.

AcknowledgmentsThis project was supported by funding from Dairy NSW. The technical expertise of Scott Richards and Michael Davy is greatly appreciated along with the biometrical analyses carried out by Terry Launders. Contributions from the range of private companies involved is gratefully acknowledged.

ReferencesMuir CE, Griffiths N, Beale P (2011) The value of ‘alternative’

nitrogen fertiliser products on pasture. 1. Pasture production at three sites. In ‘Proceedings of the 26th annual conference of the Grassland Society of NSW’. (Eds G Lodge, J Scott, W Wheatley). pp. 142 (NSW Grassland Society Inc: Orange)

Trenkel ME (2010) Slow- and controlled-release and stabilised fertilisers: an option for enhancing nutrient use efficiency in agriculture. Second Ed (IFA Paris, France).. Available at: www.fertilizer.org.

Watson CJ, Laughlin R J, McGeough KL (2009) Modification of nitrogen fertilisers using inhibitors: opportunities and potentials for improving nitrogen use efficiency, IFS Proceedings 658, 1−40.

Figure 2. Carryover effects of fertiliser treatment on dry matter production of ryegrass in winter and spring 2009 at Tocal, NSW. Values are the mean of four replicates and vertical bars represent the l.s.d. (P = 0.05) among treatments at (i) harvest 1, (ii) harvest 2, and (iii) harvest 3.



The use of pig manure – a study at Wollun, NSWC. EdwardsA and M. DuncanB

ADepartment of Primary Industries, Armidale. BNorthern Agriculture, Armidale; [email protected]

Abstract: A study of pig manure as a soil ameliorant was carried out on a granite soil on the northern Tablelands of NSW. Pig manure was applied at two rates over a period of three years. The study continued for a further six years. Soil test results showed no substantial changes in pH. Application rates directly affected soil phosphorus levels. There was a notable increase in pasture herbage mass and small positive effect on pasture quality.

Key words: pig manure, acid soils, aluminium, phosphorus

IntroductionIncreasingly, animal manures are being considered as alternative fertiliser products to add nutrients to pastures and crops. As a fertiliser, these manures can offer both macro and trace nutrients. Producers also value the reported additional benefits of supplying organic matter and improving soil biology. In some cases, manures and organic materials can be cost effective compared with manufactured fertilisers.

A replicated experiment investigating pig manure was established at Wollun on the northern Tablelands of New South Wales (NSW) in February 2001. Originally, the aim was to determine if pig manure was act as a liming agent to correct soil acidity. Some manures can be alkaline or neutral in nature, and may have a role in improving acid soils. Acid soils are one of the main forms of soil degradation, contributing to crop and pasture production limitations on the northern Tablelands (Edwards et al. 2009). This study complemented a lime movement study conducted at this site (Edwards 2004).

This paper reports the effect of topdressed manure at three rates (0, 5 and 10 t/ha) applied in each of the first three years of the experiment on soil pH, soluble aluminium at depth and phosphorus (P) on a fine granite soil over nine years. The paper also reports the effect of the pig manure on pasture production and quality.

MethodsThe study was located at “Blaxland”, 25 km north-west of Walcha on the northern

Tablelands of NSW. The pasture was dominated by tall fescue (Lolium arundinaceum Schreb. syn Festuca arundinacea cv. Demeter) and yearlong green native perennial grases (Austrodanthonia spp. and Microlaena stipoides). Subterranean (Trifolium subterraneum) and white clover (Trifolium repens) were present when rainfall was favourable. The site consisted of a soil with a pH of 4.75–4.95 (Ca) at 0–10 cm depth and 4.85–5.05 at 10–20 cm. Initially, mean aluminium levels of 4.7% of Cation Exchange Capacity (CEC) were common in the 0–10 cm depth, and 3.2% at 10–20 cm. Cation Exchange Capacity ranged from an average 3.9 meq/100 g (0–10 cm) to 2.7 meq/100 g (10–20 cm). The experiment consisted of three manure treatments (nil, 5 t/ha and 10 t/ha dry weight) with two replications. Treatments were arranged in a randomised complete block design.Soil tests were taken prior to each application of manure. Manure was collected from piles that had been sitting for at least three months. A surface application of the manure was made in February 2001 and two subsequent applications were made in February 2002 and February 2003. Manure was applied at equivalent dry weight for each application and at the same time a sample was sent for analysis. Further soil samples were taken six months after application and repeated until August 2003. All soil samples were taken at two depths (0–10 cm and 10–20 cm). Further soil samples were taken in 2009. All soil samples were analysed for pH(Ca) and exchangeable cations. Phosphorus was measured at the 0–10 and 10–20 cm depth at six monthly intervals for the first three years.The experimental area was defoliated with a rotary mower when plant height reached


10–25 cm. Total herbage mass (kg dry matter (DM) ha) was assessed 12 times over the period 2001–09. After pasture measurements were taken the site was mown to an even height and pasture material removed from the plots. A grab sample was taken from each treatment and bulked across the two replications on four occasions (July 2001, February 2002, April 2002 and May 2002) to determine pasture digestibility and crude protein.

ResultsPig manure Following each application of pig manure a sub sample was sent for nutrient analysis (Table 1).

Table 1. Range of nutrients analysed for the applied pig manure.

Analysis RangeNitrogen (Kjeldahl) 1.6–2.1 %Total phosphorus 1.6–1.7%Sulfate sulfur 0.22–0.39%Calcium 1.2–1.6%Neutralising value 1.4–1.5%pH (1:5 aqueous) 6.2–6.7

Table 2. Effect on three rates of manure on mean pH and aluminium percentage over three years (2001–04). Values followed by the same letter within columns are not significantly different (P <0.05).

Treatment pH Aluminium % Nil 4.7 b 3.25 a5 t/ha 4.7 b 2.74 a10 t/ha 4.9 a 1.21 b

b)

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Figure 1. Effect of three rates; nil (), 5 t/ha (), 10 t/ha () of pig manure on pH from February 2001 to February 2009 at two depths a) 0-10 cm and b) 10-20 cm.

Soil pHThere was a significant manure treatment effect on pH and exchangeable aluminium at the 10 t/ha rate (Table 2). After the first three years, pH continued to be affected (Figure 1).

Soil nutrientsThere continued to be an effect of the manure on P six years after the last application (Figure 2).

Pasture quantity and quality There was an effect on the total amount of pasture grown in the two manure treatments compared with the nil treatment (Figure 3). The total amount of pasture in the manure plots was about 1.4–1.5 times that of the nil plots. Pasture quality samples were also taken at irregular intervals. A summary of pasture crude protein and digestibility values for 2001–03 is shown in Table 3.

DiscussionPig manure contains a range of nutrients which can supply essential nutrients to pastures. At this site, the use of pig manure was initially aimed at investigating the potential as an alternative to lime on an acid soil. An increase in pasture production, pH and soil P occurred even at the lower rate of 5 t/ha.

While there was a marginal, but significant increase in pH and a similarly small reduction in aluminium on the 10 t/ha treatment, economic and management difficulties may limit a larger


0

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Figure 3. Total herbage mass (kg DM/ha) for the three rates; nil (), 5 t/ha (), 10 t/ha () of pig manure over the period August 2001 to September 2009.

Table 3. Effect of manure (nil, 5 and 10 t/ha) on crude protein and digestibility (%) at Wollun NSW. Values are averaged for four samples taken between 2001–03.

TreatmentCrude protein (%

DM)Digestibility (%

DM)0 t/ha 10.2 63.15 t/ha 11.6 67.910 t/ha 11.9 67.3

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Figure 2. Effect of three rates; nil (), 5 t/ha (), 10 t/ha () of pig manure on P (Colwell) from February 2001 to February 2009 at two depths a) 0-10 cm and b) 10-20 cm.

scale application. Phosphorus levels also showed a significant increase due to the addition of pig manure. Given the ongoing positive effect after nine years, an interesting question remains as to how long this effect will last.

Since this was not a comprehensive study on the effects on pig manure on pastures and soils, the results must be read with some caution. Further studies on the economics of pig manure should be undertaken.

The potential for nutrient loss, the amount of manure required to give significant pasture growth response and necessary environmental

issues, such as Environmental Protection Act guidelines and animal health implications need to be examined. Certainly, further studies should be carried out to investigate the effects of manure on soil biology, soil carbon and potential use on different soil types and pasture mixtures.

AcknowledgmentsInitial funds to conduct this study were provided by the Acid Soil Action Program for the first three years. The assistance of the site owners Caroline and Jim Street, “Blaxland”, Wollun and the Bergen op Zoom and Ohio (BOZO) Landcare groups is gratefully acknowledged. Data analysis by Bruce McCorkell and technical advice by Carol Harris, Department of Primary Industries, Tamworth and Glen Innes, respectively is appreciated.

References Edwards C, Duncan M, Harris C, Burgess A (2009) A lime

movement experiment, Walcha NSW. In ‘Proceedings of the 24th Annual conference of the Grassland Society of NSW’. (Eds D Brouwer, N Griffiths, I Blackwood). pp. 79–81. (NSW Grassland Society Inc.: Orange)

Edwards C (2004) The B.O.Z.O lime movement study at Wollun on the Northern Tablelands. In ‘Proceedings of the 19th Annual conference of the Grassland Society of NSW’. (Eds S.Boschma, G Lodge). pp. 124–125. (NSW Grassland Society Inc.: Orange)


Poster papers


Investigating the impact of cover cropping on a native pasture system in southern Queensland

L. BaileyA,C, S. MurphyB,C and C. GuppyC AGriffiths Agriculture, PO Box 1044, Goondiwindi Q, 4390; [email protected].

BDepartment of Primary Industries, Tamworth, NSW, 2340. CUniversity of New England, Armidale, NSW, 2351.

Abstract: Initial data showed that cover cropping with barley increased (P <0.05) peak standing dry matter in a summer-active native perennial grass-based pasture, which had high ground cover, despite little rain and low soil moisture. Ground cover (%) increased (P <0.05) under cover cropping with the addition of nitrogen, particularly where initial ground cover values were low. Further measurements of stored soil water, total herbage mass and ground cover over the 2011 season will enhance our understanding of the potential for cover cropping in south-east Queensland cropping belt.

Key words: pasture cropping, ground cover, dry matter

IntroductionGrowing cereals in northern New South Wales and south-east Queensland generally involves annual winter cropping preceded by a period of fallow (Hayman and Alston 1999; Marley and Littler 1989). The soils cropped in these areas are clays with a relatively high water-holding capacity and are often associated with brigalow (Acacia harpophylla) vegetation (Freebairn et al. 2009). Soil fertility in the region has decreased due to a reduction in the levels of soil organic carbon and total nitrogen (N) as a direct result of soil erosion and continuous cropping (Marcellos and Felton 1992). Cover cropping (i.e. direct drilling a winter annual cereal crop into a living native perennial grass-based pasture exploiting the differential growth patterns of the crop and the pasture while minimising damage to the pasture itself), which has been gaining popularity and interest among farmers throughout eastern Australia (Waters et al. 2008), may be a way of confronting the shortfalls for annual cropping and fallows by producing more biomass and providing year-round ground cover, intercepting more light for photosynthesis and providing less opportunity for weed germination and soil erosion (Bruce and Seis 2005). To explore the potential of cover cropping in south-east Queensland we investigated the impact of cover cropping on total plant dry matter of a native pasture system.

MethodsAn experimental site was established on a summer-active native perennial grass-based pasture (dominated by Bothriochloa macra and Dicanthium sericeum) at “Biribindibil” (28° 24’42” S, 140° 50’1”E), Toobeah, about 50 km west of Goondiwindi, Queensland in 2009. The site consisted of two side-by-side paddocks, one with low ground cover (<40%) and the other with high ground cover (>70%). Four replicates of four treatments were randomly allocated to plots (4 x 20 m) in each paddock. Treatments (native pasture, tilled native pasture, native pasture cover cropped with barley (Hordeum vulgare cv. Grout) and native pasture cover cropped with barley plus N), commenced on 24 June 2009. Nitrogen (50 kg N/ha) was applied as urea by surface spreading at the time of planting, targeting both crop and pasture in the native pasture cover cropped with barley+N treatment. A custom-built tilco tyne planter with press wheels was used for sowing the barley using four tynes on a 25 cm row-spacing. The tilled native pasture treatment was applied by using two passes of the planter without press wheels. Peak standing dry matter (kg DM/ha) was assessed by harvesting total (native pasture+barley) plant dry matter from a single quadrat [1 x 1 m] per plot on 30 March 2010. Treatments were not grazed by livestock, but native animals were not excluded.

Results and discussionIn the first season of the study, rainfall was below average and stored soil moisture was low



(<200 mm) resulting in a poor stand of barley. However, total plant dry matter was significantly greater (P <0.05) for treatments in the high ground cover paddock compared with low ground cover paddock (Table 1). For treatments in the high cover paddock, sowing barley or sowing plus added N significantly increased (P <0.05) total plant dry matter by 56% compared with native pasture alone (Table 1). While the tilled native pasture had indications of more dry matter compared with the native pasture for both low and high ground cover situations, the differences were not statistically significant.

Cover cropping with barley plus the addition of N almost doubled ground cover (from 50 to 80%) when compared with the other treatments (Table 1). With low rainfall, soil moisture was limited and so the barley crops did not progress through to the harvestable grain stage. Where ground cover was already high (>70%), the benefit of additional herbage mass generated by cover cropping was minimal, particularly considering the expense associated with generating the higher herbage mass.

In winter, the summer-active native perennial grasses were frosted or dormant, reducing the amount of ground cover in both the high and low ground cover paddocks. Summer-active species respond to seasonal rains in spring and summer, increasing ground cover. The addition of N not only improved growth of the sown barley, but appeared to bolster growth of the native species. To determine the exact role

of barley in the ground cover response would require the inclusion of another treatment of native pasture with N applied.

Measurements of stored soil water, total herbage mass (using a higher sample number within each plot) and ground cover over the 2011 season will further our understanding of the potential for cover cropping in the south-east Queensland cropping belt.Acknowledgments This study was possible thanks to the collaboration of Mr Alex Sullivan, “Biribindibil”.ReferencesBruce S, Seis C (2005) Lift ground cover and reduce drainage

with pasture cropping. In ‘Farming Ahead.’ pp. 2.Freebairn DM, Wockner GH, Hamilton NA, Rowland P

(2009) Impact of soil conditions on hydrology and water quality for a brown clay in the north-eastern cereal zone of Australia. Australian Journal of Soil Research 47, 389−402.

Hayman PT, Alston CL (1999) A survey of farmer practices and attitudes to nitrogen management in the northern New South Wales grains belt. Australian Journal of Experimental Agriculture 39, 51−63.

Marcellos H, Felton WL (1992) Cropping systems of the temperate summer rainfall region. In ‘Proceedings of the 6th Australian Agronomy Conference’. (Eds KJ Hutchinson, PJ Vickery). pp. 48−53. (The Australian Society of Agronomy; Parkville)

Marley JM, Littler JW (1989) Winter cereal production on the Darling Downs − an 11 year study of fallowing practices. Australian Journal of Experimental Agriculture 29, 807−827.

Waters CM, Hacker R, Howling G, Hulme T (2008) Report to Western, Namoi and Border-Rivers, Gwydir Catchment Management Authorities.

Table 1. Total plant dry matter (kg DM/ha) on 30 March 2010 and ground cover (%) on 7 October 2010 at “Biribindibil”. Values followed by the same letter in each column are not significantly different (P >0.05).

Treatment Pasture Dry matter (kg DM/ha)

Ground cover (%)

Native pasture

Lower cover

1820c 50bc

Tilled native pasture 1890c 40c

Native pasture cover cropped with barley 1910c 40c

Native pasture cover cropped with barley+50 kg N/ha 2160c 80a

Native pasture

Higher cover

2340bc 60b

Tilled native pasture 3020ab 50bc

Native pasture cover cropped with barley 3550a 40bc

Native pasture cover cropped with barley+50 kg N/ha 3290a 80a


Managing tropical perennial grasses for livestock production – a case studyB.R. McGufficke

Department of Primary Industries, Inverell NSW 2360; [email protected]

Abstract: On Tom Bowmans property “Tarploy” near Barraba, 190 ha of tropical perennial grass pastures have been established over several years. Paddocks are divided into blocks of 10 to 15 ha using single wire electric fencing with watering points supplied to each paddock. When the tropical perennial grasses are actively growing (November−February) Tom tries to use a stocking density of about 250 animals/10 ha and moves stock to the next block every 3 to 5 days, allowing 15 days for the pasture to recover before the next grazing. Stock are generally moved when there is 1200 to 1500 kg DM/ha left in the paddock.

Key words: filling feed gaps, pasture quality, livestock growth rates

IntroductionThere has been a widespread interest in tropical perennial grasses over the past 10 years and a rapid increase in the area sown. Estimates from commercial seed sales in New South Wales (NSW) indicate that over 250,000 ha have been sown in the last three years. This has greatly improved the pasture feedbase in northern inland NSW, providing increased options for producers over the warmer months of the year.

Tropical perennial grasses are drought tolerant and can produce up to 20 t/ha of dry matter (DM) in a growing season (Harris et al. 2010). These grasses also have a role in providing persistent perennial species in the landscape and year round high levels of ground cover if well managed. Tropical perennial grasses have high water use efficiencies compared with native perennial grasses. In trials in the Tamworth region, Premier digit grass (Digitaria eriantha) produced almost 30 kg DM/ha for each millimetre of water used (Harris et al. 2010).

Good soil nutrition is essential for tropical perennial grasses to achieve optimum growth and quality for animal production. Given adequate moisture these grasses are responsive to increased nitrogen (N) and as a rule of thumb, can produce an additional 100 kg DM/ha in the growing season for every kg/ha of N applied (Harris et al. 2010).

Tropical perennial grasses grow quickly and one of the biggest challenges is to maintain high feed quality. This can be achieved with both good plant nutrition and appropriate grazing management strategies. Plant nutrition can be improved by applications of fertiliser to raise soil phosphorus, sulfur and N to a productive level for tropical perennial grasses, and replace these nutrients (particularly N) when required. Well managed legumes can supply much of the N required by these grasses.

Effective grazing management should be planned to maintain pasture in the vegetative growth stage prior to stem elongation as pasture quality declines rapidly when stem elongation is initiated. When there is good soil moisture and fertility, and warm summer conditions, tropical perennial grasses have high growth rates and require regular grazing at high stocking densities to maintain the high quality, leafy pastures required for maximum livestock production.

Case Study – Tom Bowman, “Tarpoly”, BarrabaProducers are recognising the important role tropical perennial grasses have in filling gaps in the feedbase to increase production and sustainability. Tom Bowman is an excellent example of a producer who is using tropical perennial pastures to increase cattle production on the family property.

Tom said they have established 190 ha over several years with a mixture of Premier digit grass, Katambora Rhodes grass (Chloris gayana),


Bambatsi panic (Panicum coloratum var. makarikariense) and Gatton panic (Megathyrsus maximus). The pasture has been sown after at least 2 years of growing oats for winter fodder and controlling weeds throughout the crop and fallow periods. Tropical grasses are direct drilled in early to mid November, following the final oat crop, with adequate seed to establish 10 plants/m².

Paddocks are divided into blocks of 10 to 15 ha using single wire electric fencing with watering points supplied to each paddock. Tom realised that for maximum livestock production he needed small paddocks and high stocking rates to maintain the tropical grasses at the leafy growth stage –Phase II (Prograze Manual 2006) in periods of peak growth. During the warmer months when the tropical perennial grasses are actively growing (November−February) Tom tries to use a stocking density of about 250 animals to 10 ha and moves stock to the next block every 3 to 5 days, allowing 15 days for the pasture to recover before the next grazing. Stock are generally moved when there is 1200 to 1500 kg DM/ha left in the paddock and ideally placed into the new paddock before stem elongation commences (late Phase II).

Soil nutrition is maintained at a moderate to high level on “Tarpoly” and additional N is applied to increase pasture growth, and maintain protein levels, when required. Dry lick supplements have been used to maintain livestock weight gains if pasture quality deteriorated due to seed head initiation when insufficient cattle were available to maintain grasses at the leafy growth stage.

Tropical grasses increase livestock production on “Tarpoly” by providing greatly increased quality fodder in the late spring/summer months. This increased fodder allows Tom to purchase trade steers in spring and fatten them during this period of rapid grass growth. He says it can be difficult to keep these grasses at the leafy growth stage as large stock numbers and strict rotational grazing are required. However, by maximising the energy and protein of his pasture, Tom has been able to achieve livestock growth rates of about 1.5 kg/hd/day. He gave an example of a mob of steers that increased from an average weight of 400 kg to 480 kg over 50 days of grazing perennial tropical grasses.

Another important addition these grasses provide to the feedbase on “Tarpoly” is filling the autumn feed gap for weaners. Tom stated that their native pastures only provide low quality fodder in autumn which is unsuitable for weaners. However, with well planned grazing, tropical grasses will provide suitable pastures through late summer/autumn, until oats are available for winter fodder.

AcknowledgmentsThe author thanks Tom Bowman for sharing the valuable information on tropical perennial grass management contained in this case study.

ReferencesHarris CA, McCormick LH, Boschma SP, Lodge GM (eds)

(2010) Tropical Perennial Grasses for Northern Inland NSW. (Bookbound Publishing Pty Ltd: Gumma)


Benefits and uses of plantain (Plantago lanceolata) cv. Ceres Tonic in livestock production systems in New South Wales

H.G Judson and A.J.E. Moorhead

Agricom, P.O Box 3761 Christchurch; [email protected]

Abstract: This paper highlights some key attributes of plaintain (Plantago lanceolata) as a forage species and outlines the generic benefits of plantain cv. Ceres Tonic, It explores four different ways of using Tonic plantain as a component of perennial pastures, as a companion with either summer-growing brassicas or lucerne and as a monoculture.

Key words: pasture mixes, medicinal herb, lactation feed

IntroductionNarrow-leaved plantain Plantago lanceolata has had a long history of use as a forage plant being sown in pasture mixes in the United Kingdom and Europe since the 1700s (Foster 1988). Plantago lanceolata is highly valued as a medicinal herb and is known to contain many biologically active-compounds.

As a grazing herb, the species was first introduced as proprietary cultivars into the Australasian seed industry via the AgResearch cv. Grassland Lancelot closely followed by the Agricom cv. Ceres Tonic in the mid to late 1990s. Since this time it has become an important addition to pasture mixes, and more recently has been used as a monoculture.

This paper highlights the generic benefits of Tonic plantain and explores four different ways plantain is being used commercially in livestock production systems.

Key attributesPlantain has some key attributes as a forage species. These are;1. Excellent dry matter production, particularly

winter activity (Moorhead and Piggot 2009). In many environments, plantain produces similar amounts of forage to perennial ryegrass. A feature of plantain’s productivity is its rapid response to moisture in autumn.

2. Rapid rumen degradation rates (Burke et al. 2000) for improved dry matter intake (Judson et al. 2009).

3. Increased performance of sheep compared with ryegrass during lactation (Judson et al. 2009) and post-weaning (Moorhead et al. 2002).

4. Increased supply of trace elements to grazing livestock, resulting in increased liver concentrations of particularly copper, cobalt, and selenium (Moorhead et al. 2002).

5. Reduced impact of internal parasites. Ewes grazing Tonic plantain had significantly lower faecal egg concentrations than their counterparts grazing ryegrass (Judson et al. 2009).

Ways of using plantain1. Tonic as a component of a perennial

pastureThe initial use of Tonic plantain in Australia was as a companion species in pastures mixes. Although pastures benefited from the inclusion of Tonic, the need to spray many perennial pastures for weeds such as capeweed and thistle species, limited the area of adoption because many of the herbicides used were equally effective on plantain. As a companion species, Tonic plantain improves summer quality, autumn recovery and winter activity of perennial pastures.

2. Tonic as a companion with a summer brassica

Tonic has been widely used as spring-sown component of a brassica crop. Jacobs et al. (2006) reported that plantain (along with chicory) sown with summer forage brassica crops in the spring can increase forage production in the following autumn, and reduce weed ingression into newly sown pastures in their first year. The presence of


plantain in a brassica crop can also mitigate, to some degree, animal health issues which can arise on brassica monocultures from time to time.

3. Tonic as a mono-cultureThe experience gained in summer brassica crop mixes led to the evaluation of Tonic plantain as a monoculture. Initially, this work focussed on summer liveweight gain of weaned lambs. In these studies, Tonic plantain supported greater liveweight gain and a higher stocking rate than those grazing perennial ryegrass and also elevated liver copper and selenium concentrations (Moorhead et al. 2002). Although the liveweight gain potential of Tonic in summer is greater than ryegrass, it is generally less that of summer legumes, summer brassica and chicory.

More recently Judson et al. (2009) evaluated Tonic plantain as a lactation feed for twin-bearing ewes lambing in August. The winter and early spring activity of Tonic provided sufficient feed to support twin-bearing lactating ewes in early spring. The ability to consume more plantain, probably as a result of its fast rumen degradation rates, improved the weaning weight of the lambs by between 10 and 34% over the four years of studies. Ewes were also heavier at weaning by up to 14 kg. In a farm system, where the sale of cull ewes or last-lambing ewes is a valuable income stream, using a lactation forage that puts weight on the ewe by weaning is a real asset.

4. Tonic as a companion with lucerneLucerne systems are characterised by excellent summer growth, particularly in hotter, drier environments. Although specific genotypes of lucerne have been bred for increases in winter activity, this may come at the cost of persistence. Where lucerne is used in sheep systems in drier environments, winter-active species need to be included in the farming system to fill feed gaps left by inactive lucerne in winter and early spring. Such species have included cereals and short rotation ryegrass. More recently, adding Tonic plantain to lucerne stands has provided valuable feed in early spring and late autumn, which complements the summer production of lucerne.

ReferencesBurke JL, Waghorn GC, Brookes IM, Attwood GT (2000)

Formulating total mixed rations from forage – defining digestive kinetics of contrasting species. Proceedings of the New Zealand Society of Animal Production 60, 9–14.

Foster L (1988) Herbs in pastures. Development and research in Britain, 1850-1984. Biological Agriculture and Horticulture. 5, 97–133.

Jacobs JL, Ward GN, Maskell P, McKenzie FR (2006) Contributions of a herb and clover mix to spring sown and autumn sown forage for dryland dairying. Proceedings of the New Zealand Grasslands Association 71, 201–205.

Judson HG, McAnulty R, Sedcole R (2009) Evaluation of ‘Ceres Tonic’ plantain (Plantago lanceolata) as a lactation feed for twin-bearing ewes. Proceedings of the New Zealand Grassland Association 71, 201–205.

Moorhead A J E, Judson HG, Stewart AV (2002) Liveweight gain of lambs grazing ‘Ceres Tonic’ plantain (Plantago lanceolata) or perennial ryegrass (Lolium perenne). Proceeding of the New Zealand Society of Animal Production 62, 171–173.


Australian breeding of persistent perennial ryegrass without endophyteA. Leddin

Valley Seeds Pty Ltd., 295 Maroondah Link Hwy, Yarck, Victoria 3719; [email protected]

Out of the four perennial grasses cocksfoot, perennial ryegrass, phalaris and tall fescue, perennial ryegrass would be highest selling species sold in Australia. Perennial ryegrass has been popular due to its ease of establishment, management and good forage quality. Perennial ryegrass is also a commonly used species in New Zealand and Europe for forage and north America for turf. A majority of the perennial ryegrasses used in Australia are bred in those countries and then marketed in Australia. There are over 6 million ha of perennial ryegrass based pastures in Australia (Reed 1996). The majority of the perennial ryegrass material used in overseas breeding programs is based on germplasm originally collected from northern European or southern Mediterranean germplasm regions. However there has been little work done with north African based material which has summer dormancy characteristics which may be of significant value in the hotter, drier climate of Australia. Currently available perennial ryegrass cultivars are generally suited to an annual rainfall of >650 mm. With climate change, the predictions are that annual rainfall will decrease and temperatures will increase. If this occurs, then unless a far greater effort is placed on breeding cultivars better suited to Australia’s environment we are likely to see a the current perennial ryegrass zone shrink as a result of poor ryegrass persistence.

Perennial ryegrass plants can contain endophyte. Endophyte is a fungus that often occurs in perennial ryegrass as well as some other perennial grasses. The natural form of endophyte often causes the syndrome known as ‘ryegrass staggers’. The affects on livestock and subsequent costs to producers are significant. New Zealand research has selected novel endophytes existing in nature and inserted these into ryegrass plants to retain positive effects of insect resistance and reduce negative animal effects. One of the

major claims about endophyte is that endophyte is required in a variety for it to be persistent. Some Australian trials have demonstrated that Australian bred perennial ryegrass is potentially better adapted to some regions than perennial ryegrass bred overseas. As a result of these trials the evidence is mounting that an important consideration when selecting a cultivar should first be how well adapted is it to the region and use that the farmer requires and then after that endophyte issues should be considered.

One advantages that perennial ryegrass has as a species is its diversity in heading dates or maturity. It begins to head from 6 October to the 27 November. This difference in the heading dates can be used to select the right variety for a specific location and may also help with persistence. Perennial ryegrass usually has a spring dry matter (DM) production peak of nearly 60% of its annual DM production close to its heading date. Allowing perennial ryegrass to head can help increase persistence. To take advantage of this peak it is important to match the right heading date in the right environment. Early heading perennial ryegrass varieties which are based on the Australian Kangaroo Valley germplasm such as Boomer, Roper and Fitzroy, have the DM production peak in late winter/early spring, so these varieties are best suited to early country rather than late country. These early varieties still need adequate rainfall to persist. The mid heading varieties are your ‘all rounder’ that can be used in most locations including dry and wet. Examples of these are Camel, Avalon and Victorian. Late heading varieties are best suited to high rainfall, late country that holds moisture into early summer. This is usually on flats or on the southern slide of slopes. All late heading varieties are bred overseas and include Platinum, Banquet II and Bealey.

Medea was one of the most persistent perennial ryegrass variety ever introduced into the


Australian market, Medea, had low endophyte (Table 1). Medea had the ability to go dormant in summer, giving it greater persistence than the non-summer dormant varieties. Currently there are no summer dormant perennial ryegrasses available in Australia. Anthony Leddin, Valley seeds plant breeder, through his award of the 2009 Young Scientist of the Year for Meat and Livestock by MLA is developing summer dormant perennial ryegrasses with low endophyte that will persist longer than any variety available in Australia. Leading advocate of Australian pasture research, Dr Kevin Reed, states in one of his papers that ‘Algerian derived lines of perennial ryegrass (with low endophyte) may become a valuable genetic resource for the development of safe, persistent cultivars’ (Reed et al. 1987).

In trials at various locations in Australia, it has been demonstrated that the key to persistence of a plant is breeding with germplasm suited to Australia in Australia. New Zealand breeding in perennial ryegrass has gone down the path of selecting for novel endophytes to try and increase persistence and have no side effects on animals. Most New Zealand perennial ryegrasses have begun with European germplasm material selected from central Europe followed by material selected from southern Europe. Australian breeding has gone down a different pathway. Many varieties developed in Australia have used Victorian or Kangaroo Valley perennial ryegrass as their base. These plants were adapted to the Australian environment from the original seed brought over from England over 100 years. It has been shown to be very persistent and hardy in Australian conditions and some varieties even persist without endophyte. Results from a trial at Balmoral in Western Victoria, with an annual rainfall of less than 600 mm, less than

what is recommended to maintain perennial ryegrass stands, show that the persistency of perennial ryegrass bred in Australia without endophyte was greater than those bred in New Zealand with endophyte (Table 1) and both had a similar heading date. This may have also been due to the varieties being able to go dormant in the summer. Persistency is important not only due to the extra cost that is involved in having to resow pastures but also when desirable plants die these are usually replaced with weeds. There is a time and economic cost in controlling weeds and the weeds also place more pressure on existing desirable plants within the pasture for moisture and nutrients.

A good example of the breeding with Australian germplasm for persistency is the program from Valley seeds in the development of Camel perennial ryegrass, a nil endophyte variety. It was selected from Victorian perennial ryegrass plants that were surviving at St Arnard, which has an annual rainfall of 550 mm and had also survived the 1982 drought. Hamilton is on the border of a marginal environment for perennial ryegrass to grow. This is the location where Valley Seeds carry out certified seed production of its Australian bred perennial ryegrass. These paddocks are selected for production of certified seed on the basis that there is less than 1 in 10m2 of another ryegrass. Certified seed paddocks of Camel ryegrass with nil endophyte in this region have persisted well beyond the three year period of certified seed production and even through the 2006 drought.

The results from the trial in Yarck, a site that has an early finish to the season (Table 2) suggest that Australian bred or background based material to have greater persistence than material bred in New Zealand, in a tough

Table 1. Persistency trial Balmoral Western Victoria, DPI Hamilton in 1991 and 1995.Species Cultivar/ecotype Plant density 1991

(no/m2)Plant density 1995

(no./m2)% density

Perennial ryegrass Medea material (LE) 801 73 9.1Perennial ryegrass Brumby (Vic x Medea)(LE) 753 31 4.1Perennial ryegrass Kangaroo Valley (SE) 486 16 3.3Perennial ryegrass Ellett (SE) 1111 40 3.6Note: LE = Low endophyte, SE = Standard endophyte. LSD for Plant density (no./m2) in 1995 (P = 0.05) = 16.6.


Australian environment. This may be due to a number of factors including:• Adaptationof theparentalmaterial to the

Australian environment of over 100 years• Theappropriateheadingdate,earlyandmid

heading would be more suitable to most Australian environments than late heading when it comes to persistence.

• Itispossiblefornilorlowendophytematerialto persistence in the absence of insect pests as long as it has strong genetics for persistence.

Entry Den070710 Endophyte Type BreedingCamel 96.25 Nil Australia (Valley Seeds)Victorian 94.5 High Wild Australian EcotypeFitzroy 94.25 High Wild AustraliaBoomer 93.75 Nil Australia (Valley Seeds)Prolong 92.75 Nil Australia (Valley Seeds)Avalon 92.5 High Wild AustraliaKangaroo Valley 92.25 High Wild Australian EcotypeMeridian AR1 90 High AR` New Zealand (Kangaroo Valley cross)Roper 88.5 Nil Australia (Valley Seeds)Arrow AR1 88 HIgh AR1 New ZealandBolton 87.75 High Wild AustraliaCommando 87.6 High AR1 New ZealandPlatinum 87 Low Wild New ZealandSamson 86 High Wild New ZealandKingston 85.75 High Wild New ZealandBealey 85.5 High NEA2 New ZealandBanquet II 85 High Endo5 New ZealandRevolution 85.5 High AR1 New ZealandAlto AR1 84.25 High AR1 New ZealandMatrix 84 HIgh Wild New ZealandPG one 50 83.5 High AR1 New ZealandExtreme AR1 83.25 High AR1 New ZealandNZ – LP9904 82.5 Nil New ZealandTrial Mean 88.5LSD (5%) 5.8% CV 4.6

Equ

ival

ent t

o ea

ch o

ther

Table 2. Plot density (%) on 7/7/10 at perennial ryegrass trial, Yarck central Victoria, Sown 18/4/08.

References Reed, KFM, Cunningham PJ, Barrie JT and Chin JF (1987)

Productivity and persistence of cultivars and Algerian introductions of perennial ryegrass (Lolium perenne L.) in Victoria. Australian Journal of Experimental Agriculture 27, 267–274.

Reed, KFM (1996) Improving the adaptation of perennial ryegrass, tall fescue, phalaris and cocksfoot for Australia. New Zealand Journal of Agricultural Research 39, 457–464.


Effect of ensiling on weed seed viabilityJ. Piltz, R. Stanton, C. Rodham and H.Wu

EH Graham Centre for Agricultural Innovation (an alliance between the Department of Primary Industries and Charles Sturt University), Wagga Wagga Agricultural Institute, NSW, 2650.

[email protected]

Abstract: Seeds from 10 weed species were ensiled, underwent 48 hour in sacco digestion or both. Seed germination and viability were compared with untreated seeds. Ensiling reduced weed seed viability. Placement in the rumen for 48 hours also reduced viability though the effect was more variable between species. The greatest reduction in viability occurred with the combination of treatments.

Key words: weed seed, silage, viability

IntroductionBased on anecdotal evidence it is generally assumed that ensiling renders most weed seeds non-viable but this has only been scientifically tested on a very limited basis (Blackshaw and Rode 1991; Mayer et al. 2000). A preliminary experiment was conducted at the Wagga Wagga to determine the effect of ensiling on the viability of seeds of 10 Australian weed species.

MethodsWeed seeds of different species were placed in Dacron bags (50 seeds per bag) of the type used for degradability studies and ensiled for three months in chopped cereal forage. Two bags of each weed species were placed in each of four plastic bag mini-silos (replicates). Upon opening one bag of each weed species from each silo plus a bag containing 50 untreated seeds were placed in the rumen of one of four mature Red Poll steers for 48 h. Bags from each mini-silo were placed in the rumen of the same animal. Weed seed germination and viability was tested against control seeds. After 18 days ungerminated seeds were tested for viability using the tetrazolium test.

Results and discussionThe viability of untreated seeds varied with species (Table 1). Viability of wireweed seed used in this experiment was very low while that of the grass weeds was generally high. Ensiling reduced the viability of seeds. Digestion also reduced the viability of most weed seeds though the effect is highly variable. The combination

of ensiling plus digestion rendered all seeds non-viable except for those of marshmallow. It was concluded that ensiling prior to feeding to ruminants is an effected strategy as part of an Integrated Weed Management package.

Table 1. Effect of treatment on weed seed viability.

Weed species

Con

trol

Sila

ge

Dig

estio

n

Sila

ge +

dig

estio

n

Barley grass 96 0 5 0Brome grass 69 0 5 0Silvergrass 98 0 12 0Wild oats 79 5 1 0Marshmallow 58 37 33 43Paterson’s curse 31 0 16 0Prairie ground cherry 90 0 87 0Silverleaf nightshade 91 1 92 0Wild radish 41 1 8 0Wireweed 3 0 2 0

ReferencesBlackshaw RE, Rode LM (1991) Effect of ensiling and rumen

digestion by cattle on weed seed viability. Weed Science 39(1), 104−108.

Mayer F, Albrecht H, Pfadenhauer J (2000) The influence of digestion and storage in silage and organic manure on the germinative ability of six weed species (Papaver argemone, P. dubium , Legousia speculum-veneris, Centaurea cyanus , Spergula arvensis , Trifolium arvense). Zeitschrift fur Pflanzenkrankheiten und Pflanzenschutz 17, 47−54.



Travel grant report


Report of travel to New Zealand to attend the 15th Australian Society of Agronomy Conference and visit two NZ Agresearch Institutes

M.R. Norton

Department of Primary Industries, c\- CSIRO Plant Industry, Canberra; [email protected]

Purpose of travelAs Secretary of the Australian Society of Agronomy (ASA) it was essential that I attend the ASA biennial conference (held in Christchurch) to ensure the smooth running of this event. In addition, I delivered a conference paper and also visited the NZ Agresearch Institutes at Lincoln and Palmerston North to deliver a seminar about pasture grass drought survival and liaise with grassland science colleagues with a view to possible future research collaboration.

ItineraryOverseas travel commenced on 14/11/2010 and finished on 24/11/2010. Between these dates I visited:• LincolnUniversitytoattendtheconference

of the ASA; • AgresearchLincolnforliaisonwithDrsPhil

Rolston and Keith Widdup; • Agresearch PalmerstonNorth for liaison

with Dr Zulfi Jahufer and other grassland scientists.

Benefits and outcomes of the travelAs the Secretary of the ASA my activities were focussed on ensuring the successful staging of the Society’s conference. Through this conference, (Theme – ‘Food security from sustainable agriculture’) the media profile and importance of agronomy to the Australian economy, society and environment were raised. This is important given the Productivity Commission Review of Australian Rural Industry R&D, ongoing concerns about World Food Security and Murray–Darling Basin water use negotiations. My visits to Agresearch Institutes at Lincoln and Palmerston North were helpful to ensure the ongoing seed production of the most drought tolerant perennial pasture grass in Australasia, Kasbah cocksfoot,

while establishing links with scientists who share my research interest in improving the drought resistance of pasture grasses.

Major activitiesActivity 1The 15th Australian Society of Agronomy Conference at Lincoln, New Zealand.

This conference was jointly staged by ASA, the NZ Grassland Association, the NZ Agronomy Society and the NZ Soil Science Society. This was the first time that the ASA Conference has been staged outside of Australia. Overall, there were 510 conference registrants from 14 different countries with 145 of these being Australian while 341 were from NZ. Of the other participants seven were from China, three each were from India and Tanzania, two each were from Brazil and Japan, while one each was from Chile, France, Indonesia, Ireland, South Korea, Russia and USA.

Professor Peter Cornish, a former scientist with NSW Agriculture, was awarded the most prestigious accolade of the ASA, the C.M. Donald Medal. Peter’s subsequent Donald Oration extolled the benefits of undertaking farmer participatory research and his humility and enthusiasm inspired his listeners.

Conference plenary presentations covered a diverse range of topics including: 1. Can we feed the world in 2050? (presented

by Dr Greg Edmeades, ex CIMMYT);2. Agricultural productivity in Australia and

New Zealand: trends, constraints and opportunities; (Dr Michael Robertson, CSIRO);

3. Promoting food security by supporting Agricultural R&D; (Prof. John Mullen, ex I&I NSW, now Charles Sturt University);


4. The Sustainable Use of Water Resources for Agriculture and Horticulture; (Prof. Brent Clothier, Plant & Food Research NZ);

5. Greenhouse gas fluxes in grazed pastures; (Dr Harry Clark, NZ Agricultural Greenhouse Gas Research Centre);

6. A postscript to “Peak P”– an agronomist’s response to diminishing P reserves (Prof. Peter Cornish, ex NSW Agriculture, University of Western Sydney).

Topic areas of the concurrent sessions included: Climate Change–Future Farming; Simulation and Decision Support; Crop Production–soil water and WUE; Crop Production–N and P use; Pasture production–physiology and breeding; Crop Production–precison agriculture; Crop Production–development and herbicide management; Crop Production–nutrient management; Crop Production–high rainfall zone; Crop Production–physiology & breeding; Crop Production–dual-purpose crops; Managing nutrient loss and water quality; International crop–pasture systems; Forage crop production; Intercrops/cover and companion crops; Pasture production–IPM; Pasture production–spatial management; Dairy pasture production and management.

I presented a paper entitled, ‘The effect of lime application to an acid soil on perennial grass establishment’ in one of the above concurrent sessions.

The complete Conference proceedings can be viewed at: http://www.agronomy.org.au/proceedings/index.htm

Activity 2On Friday 19 November, I visited the NZ Agresearch institute at Lincoln. While there I met with Drs Phil Rolston (pasture seed production researcher) and Keith Widdup (pasture grass breeder). I am collaborating with Dr Rolston to help in the improvement of seed production of the summer-dormant cocksfoot cultivar Kasbah. This is important for NSW because throughout the droughts of the 2000 decade Kasbah clearly had the best drought survival and production of any of the sown perennial grasses tested in NSW. Seed production of Kasbah is poor and to keep

the cultivar in commerce research is needed to improve its seed production. Dr Rolston is essentially the only pastures researcher in Australasia with a primary focus on seed production. I first met Dr Keith Widdup in 2009 at the Summer Dormancy Workshop in the USA. At Lincoln, we visited one of his tall fescue breeding nurseries and discussed the techniques used for the measurement of summer dormancy (an important drought survival trait) expression in grasses.

On Monday and Tuesday 22 and 23 November, I visited the Palmerston North Institute of NZ Agresearch. This shares a campus with Massey University and other research/industrial organisations including Fonterra. There my visit was hosted and coordinated by Dr Zulfi Jahufer, the former NSW Agriculture white clover breeder (1989−1994) at Glen Innes. While at Palmerston North I met Drs Syd Easton (Centre Director), Derek Woodfield (breeder), David Hume (agronomist-endophyte specialist), Jimmy Hatier (pasture physiologist), Bruce Veit (biochemist), Alicia Scott (biotechnologist) & Warren Williams (legume breeder).

On the first day of my visit I gave a seminar attended by approximately 30 scientists entitled, ‘Stories of summer survival and death – the case of cocksfoot’.

Although it is rare for summer droughts to actually kill pasture grasses in NZ there is a lot of interest in reducing productivity losses due to drought and this explains the high level of interest in my talk. I subsequently had good discussions with Jimmy Hatier and Warren Williams both of which could lead to some fruitful future collaborations. With Jimmy Hatier the potential collaboration could extend to a refinement of methods to measure summer dormancy in grasses, a field in which I have previously published. The discussions with Warren Williams focussed on his efforts to cross white clover with other more drought resistant Trifolium spp. with the objective of strengthening drought resistance in this species. Warren often uses annual Trifolium spp. as sources and he is confident that he understands the genetics of perenniality in this genus. I am

http://www.agronomy.org.au/proceedings/index.htm

http://www.agronomy.org.au/proceedings/index.htm


involved in the development of perennial wheat amphiploids but a key problem with these is their weak perenniality. It is possible that insights from Trifolium might help in strengthening perenniality in Triticum.

Activity 3During the weekend (between 19/11/10 and 20/11/10) I visited the dairy farm of Mr J. O’Connor, Kokatahi, via Hokitika (West Coast, South Island). This high-rainfall (+2000 mm) zone is one of the cheapest places in the world to produce milk because feed production is pasture-based (white clover/ryegrass) and as the climate is mild it is possible for the animals to remain outside on the pasture all year. A high proportion of the local milk is exported in various milk powder forms produced by the local cooperatively-owned factory. Jerseys are the major diary cattle breed used there because of their high milk fat and ease of care (e.g. calving). A high level of mechanisation is used so that on Mr O’Connor’s farm all day-to-day activities, including the milking of 200 cows (using a rotary dairy), were undertaken by one person.

General observationsBroadly speaking pastoral agriculture in NZ operates at a higher level of intensity than that occurring in most of Australia, probably because land prices are much higher. The mild temperate

maritime climate with abundant rainfall or cheap irrigation means that farmers can economically apply high levels of input to their pastures. This greater level of investment seems to occur across the board, including education. Perennial ryegrass/white clover is the preferred pasture mix with white clover providing high quality feed and the majority of nitrogen (N) to the pasture. The N fixed by white clover is crucial to the low costs of production of NZ pastoral agriculture and this is currently threatened by the clover root weevil which is decimating many NZ pastures. Biocontrol measures to control the weevil have been undertaken and are described in the paper of Dr P. Gerard.

The research group at Agresearch Palmerston North constitutes one of the larger pastoral research agglomerations in the southern hemisphere. This group is dynamic and outward-looking with scientists of international origin (e.g. France, USA) or having been trained overseas. Moreover, the scientists who constitute this group cover a wide range of disciplines from the molecular to the macro level and we should be developing closer ties with them or we risk being left behind.

AcknowledgmentsI thank the Grassland Society of NSW Inc. and the A.W. Howard Memorial Trust whose grants made this travel possible.

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