Plant Health

Native Grass Health Program

ABSTRACTHow 3 Australian Native Grasses cope when subjected to trial conditions.

Joshua Brown 031308053Diploma of Horticulture AHCPCM501A Plant Health

Table of ContentsIntroduction.......................................................................................................................................3

Body...................................................................................................................................................3

Conclusion.........................................................................................................................................4

Introduction to the grasses................................................................................................................5

Trial 1 and how it happened..................................................................................................................9

Trial 2 and how it happened................................................................................................................14

Graphs.............................................................................................................................................18

Weather...........................................................................................................................................19

References...........................................................................................................................................20

Websites..........................................................................................................................................20

Books...............................................................................................................................................20

Introduction

Western Australia has the dilemma with a massive influx of people coming into the state to live while water supplies are at record lows. Metropolitan Perth suburbs are filling fast and each house that is built puts more pressure on the dwindling water levels in dams. Farmland is sold and hundreds of houses are built in place. Suburban 2 acre blocks that once housed 2 families are snapped up and redeveloped into high density housing. Perth councils approve more building developments without having long term vision for the state. Over use of fertilisers leads to nutrients leaching into the rivers and waterways that often have algae bloom as a result. On any given Saturday the sound of the lawn mower can be heard on nearly every street corner. Perth is at a crisis point and something has to give.

Native grass trials have been established at South Metropolitan TAFE, Murdoch, Western Australia. The first trial is aimed at monitoring the plant health during the establishment of seedlings of native grass. The second trial is aimed at monitoring plant health while the weather conditions change and reacting accordingly. The trials hope to provide more data and further practical studies in developing native grasses for use as a turf ground cover alternative.

The first trial assesses three types of native grasses – Microlaena stipoides var. Burra, Rytidosperma caespitosum and Austrostipa scabra sown in plots. The second trial assesses the same varieties, except the variety Griffin instead of Burra has been used in the Microlaena stipoides plots. The second trial assesses already established plants with mowing heights at 100mm for 1/3 of the plants and 2/3 without height reduction.

Body

Previous trials with native grasses determined that native grasses were able to grow and flourish in Western Australian conditions. The 3-month trial aimed at replicating a weekly cutting height of 75mm. The results indicated that the majority of the plants had no adverse reactions to a constant reduction in height. The Microlaena stipoides var. Griffin, Rytidosperma caespitosum and Austrostipa scabra all responded to the reduction by sending more tillers out.

Weather The weather conditions will be monitored as part of analysing how the plants react to the season change. The trial plants have been in the ground for 6 months through autumn and winter. Recent literature from the Department of Primary Industries NSW suggests that the 3 species were not warm or cool season grasses, rather year-round green grasses. This may only apply to areas where sufficient rainfall and low temperatures are present unlike Western Australia. Metropolitan Perth can sometimes be described as transitional between warm and cool season.

Growing patterns, the native grasses tend to be clumping and are mainly used in pastures or grown to full height in revegetation. Microlaena stipoides produced rhizomes in the original trial, as a response to the reduction, effectively creating a wider plant. By researching the area that each plant is covering, a plant spacing recommendation can be made.

Seed for exotic species is readily available and seed viability or germination levels is high. In comparison, native grass seed is expensive and germination rates are average. To cover the area as a turf-grass it was recommended to seed the area at rates of 90 grams for 1kg per 100m2. Native grasses that are established by seed have competition from weeds due to slower growth rates. (Waters, 2001) Wallaby and Spear grass reproduce via seed dispersal and rely on germination to

significantly increase coverage. Weeping grass sent rhizomes out as well as reproduction via seed germination.

Environmentally friendly To achieve an aesthetically pleasing and healthy turf grass high levels of water, maintenance and fertilisers are required. By researching native grasses as turf applications and gathering data to compare against the exotic species, one hopes to reduce water, maintenance and fertiliser use. On the whole, exotic grass species out-perform native grasses species in aspects that appeal to the turf industry. As a result, native grasses have been excluded from most of the turf industry.

Native grasses display characteristics of turf grass that are desirable such as good year-round colour, shade and drought tolerance. Benefits of the native grasses are long term and investing in establishing a full cover takes patience. In comparison an exotic turf grass can be established with little difficulty. Exotic grasses can however, become problematic once established, such as constant maintenance and some species becoming particularly invasive.

Advantages for sowing a native lawn

Equal texture and durability Reticulation not necessarily required once established Shade and salinity high tolerance Require less maintenance, fertiliser and water compared with exotic lawns. Environmentally friendly

Disadvantages of sowing a native lawn

Weed control is a must for a good result Slow growing, slow to establish Germination very slow in winter Costly to establish as germination can be poor and it needs to be sown thickly.

Conclusion

The latest trial plots will give a thorough look at establishing a turf cover via seed as well as associated problems, challenges and insights. “Life can get so complicated, you forget what’s real, you forget what’s good. And they tell you your educated if you complicate the simple truth”. Native grasses thrived for many millennia before the introduced species and it may be time to go back to basics.

Introduction to the grassesThe species that have been selected for the trial can be described as yearlong grasses from the Family Poaceae. They are intermediate between warm season and cool season grasses; growing throughout the year if conditions are suitable and tending to flower in both spring and summer.

Rough Spear grass – Austrostipa scabra Native yearlong green perennial but mostly productive in spring and early summer. Spear Grass is a tufted perennial cool season grass. It grows in poor soils and copes with highly acidic soils. It can tolerate high temperatures and drought conditions. Spear grass remains green throughout hot summer months.

http://ausgrass2.myspecies.info/files/1auscas.jpg

Weeping Grass – Microlaena stipoides var. griffin and Microlaena stipoides var. burraWeeping grass is a slender perennial with scaly underground rhizomes and short leafy stems together with erect, longer stems bearing the seed-heads. Weeping grass naturally occurs in southern regions of Australia. It appears to prefer shady sites where the soil does not dry out in summer. Also described as a native yearlong green perennial Mircrolaena stipoides can be quite productive, can respond to increased fertility (especially nitrogen) and is tolerant of heavy grazing. These varieties are cool season grasses that have soft leaves and a weeping form. It grows in poor soils and copes with acidic soils. It can tolerate high temperatures and frost. Weeping grass can also grow in shade and drought conditions.

http://ausgrass2.myspecies.info/files/1MISTIS.JPG

Ringed Wallaby Grass – Rytidosperma caespitoseCan produce a green leaf year round if there is enough moisture. Persists and seeds prolifically unless very heavily grazed; will tend to decline if not grazed for a long time. Wallaby Grass is a cool season grass that has erect tufted fine leaves. Wallaby grasses remain green year round. Wallaby grass has been used on golf courses and in areas effected by saline, water issues as well as erosion control. Wallaby grass can also tolerate high temperatures, acidic and drought conditions.

http://ausgrass2.myspecies.info/files/1aucae.gif

Pest and Diseases

Helminthosporium gigantea Zonate Leaf Spot A disease which can kill the leaves that can be caused from bacteria. This bacterial infection can enter the plant from wounds from insect attack, hail or pruning. The bacteria can spread quickly through the cells in prolonged wet weather. The diseases reproduce on plant matter in the soil and only incedently attack the plant during prolonged cold and wet seasons. Increase fertiliser rate and plant health to assist in blights. Spray with actidione ferrate.

Black aphids HempiteraAphids are a chewing insect that produce honeydew, can transmit virus and diseases and can stunt growth in plants. Aphids are quickly becoming resistant to chemicals and so spot treatment is recommended rather than blanket spraying. Aphicides can reduce the impact on the non-target and often beneficial organisms that may be the aphid’s predator. Lacewings and parasitic wasps are natural predators that are commercially available. Aphids don’t like hot dry weather conditions.

Mediterranean snail Cochlicella acuta

Snails are likely to increase if it rains, if heavy dew or irrigation is available. They generally prefer

cooler climates and limey soils increase the fertility of snails. Snails can be treated with cultural methods such as using trickle irrigation where possible to reduce moisture. Watering early in the day to minimise moist areas. Have good sanitation by picking up anything lying around where snails can live and breed. Reduce snail populations by hand removal or baiting (some baits are more effective than others).

Nutrient deficiency

Nitrogen - Yellowing of the leaves and stems, burning of lower leaves will lead to stunted growth of overall plant. Ureaform nitrogen is a slow release product that can provide a long term solution to turf in a slow release application. Immediate improvements can be achieved with a Nitrogen based fertiliser.

Phosphorus – Mature leaves can be a bronze colour and leaf margins will be yellow. Phosphorus deficiency will also stunt growth and slow. Can be added via a superphosphate fertiliser or alternatively in an all-round complete fertiliser.

Evening Primrose Oenothera stricta

Originating in Chile and Argentina, this weed has all but naturalised in Australia. The seed germination is medium to high and this weed is persistent. Weeds take up nutrients and water destined for other plants. Manual removal is the preferred control method as the Evening primrose is relatively tolerant of herbicides once established. Glyphosate will kill the younger plants only – use chlorsulfuron to spot spray it out.

Trial 1 and how it happenedThe trial to monitor the health of native grass seedlings in plots didn’t begin until 6 th October 2016. Seed was ordered from the Victoria and was held up in Western Australian Quarantine. While waiting for the seeds to arrive the second trial continued and the plots were prepped. Preparation of the plots included removing the Buffalo grass and any other weeds, levelling and organise reticulation. The plan was to reduce costs by only broadcast seeding a 4m2 area rather than the entire 36m2. After the germination, the seedlings were monitored for growth and colour. Plots were monitored for weeds and reticulation readings noted.

1.) Microlaena stipoides var. Burra2.) Rytidosperma caespitosum3.) Austrostipa scabra

Trial 2 will commence on 6th October 2016 and involve seeding 3x3m areas of each species. The Weeping grass has changed from var. Griffin to var. Burra, however the Spear and Wallaby grass remain the same.

This trial includes three types of native grasses – Microlaena stipoides var. Griffin, Rytidosperma caespitosum and Austrostipa scabra. Growing a lawn out of Weeping, Wallaby or Spear grasses is a process that has had some successes in many parts of Australia.

Week 1 6/10/2016 Seeds broad acre cast and then raked in. The plots were monitored for weed control and reticulation was scheduled for 5 minutes, 3 times a day.

Week 2 12/10/2016 Weeping grass seed floated to surface after strong rainfall over the weekend. Control measure to use TORO to wheel roll in the seed to below the surface. Irrigation reading Wallaby 8662.7L Weeping 12425.6L Spear 12041.0L

Week 3 19/10/2016No seedlings emerging as of yet.Irrigation reading Wallaby 9123.2L Weeping 12918.0L Spear 12506.9L

Week 4 26/10/2016Weeping grass at the 2-leaf stage. The leaf is much thicker compared to the Wallaby and Spear grasses.Wallaby grass emerging slowly. The germinated seedling is thin and short in appearance and sparse. Spear grass seedlings are the tallest and fastest growing of the three varieties. There is much competition from annual weeds. The Spear grass plot had the least amount of preparation.Irrigation reading Wallaby 9542.5L Weeping 13355.6L Spear 12892.8L

Week 5 2/11/2016 Irrigation reading Wallaby 9988.7L Weeping 13833.7L Spear 13334.7L

Week 6 9/11/2016Irrigation reading Wallaby 10434.8L Weeping 14319.7L Spear 13781.9L

Week 7 16/11/2016Weeping grass seedlings are at 5-leaf stage. Overall colour loss and the yellowing is in the 2 lowest leaves, suggesting a nitrogen deficiency. Wallaby grass seedlings are very sparse and slow growing. Little noticeable change over the week.Spear grass seedlings height noted in most plants of between 3-5cm. Some areas of the trial have established thicker and faster than other areas. Product applied at a rate of 400kg/ha equivalent to 1.44kg per plot.Irrigation reading Wallaby 10888.4L Weeping 14807.5L Spear 14207.8L

Week 8 23/11/2016 Weeping grass has not responded much to the fertiiser. Lower leaves still showing a yellowing suggesting a nitrogen deficiencyWallaby grass is very thin and sparse. Wallaby smallest/worst cover, this may be to poor germinationSpear grass displaying the best growth patterns, so far and Possibly due to temperature. 8-12 tillers per plant and is 4-5cm in height. There are some patches where the grass is growing better –

possibly due to different reasons. Some possible readable results may be that the germination of the seed in that particular area was better or that more seed was raked into that section of the trial.Irrigation reading Wallaby 11214.0L Weeping 15155.5L Spear 14500.0L

Microlaena stipoides var. Burra seeds

risen to the surface after heavy rainfall

Control measure

Using the TORO to roll in the seeds beneath

the surface again

Spear grass emerging

Wallaby grass emerging

Weeping grass emerging

Spear grass 16th November

Wallaby grass 16th November

Weeping grass 16th November

Trial 2 and how it happenedThe trial to monitor the health of native grasses began June 9 th 2016. The plants to be monitored had been established in the plot area since March 2016. The height and width of 15 plants from each species were recorded and the plants were photographed. Apart from one plant that had died in the previous trial, the same plants were selected for measurement recordings.

1.) Microlaena stipoides var. Griffin – Weeping grass2.) Rytidosperma caespitosum – Ringed Wallaby grass3.) Austrostipa scabra - Spear grass

The 3 species were germinated in the later part of 2015 and then planted out in separate plots in late February 2016. Each 2m2 plot had 25 of each species planted at 400mm spacing’s. The plants have been in the ground for over 7 months. The original trial focused on how the species responded to a reduced height, irrigation and no nutrient improvement.

The next stage of the trial will focus on keeping the established species in the plots, however reducing the number of plants subjected to a weekly height reduction. Plot B of the trial will be kept at 100mm and Plots A and C will be grown without reduction. After the original trial 1/75 Spear grass was in poor health, 2/75 Wallaby were dead and 2/75 were unhealthy and 2/75 Weeping grass had almost died but were making a comeback. The plots had large amounts of weed infestation and this was manually controlled during the trial. Some black aphids were noted on one of the wallaby grass plants in June.

Week 1 9th June 2016

Spear grass healthy with a dark green/emerald colour. The spear grass early stage of producing seed.

Wallaby Grass has several specimens in poor health as noted be lack of tillers and dead tillers. The wallaby grass is also yellowing on the edges of the leaf.

Weeping grass healthy with a dark green appearance, also now in the stages off seeding. Continued rhizomatous activity without weekly height reduction.

9/9/2016 Fertiliser application in reaction to the weather increasing in temperature.

36 grams of Nitrogen in the form of Urea 18 grams of Potassium in the form of potassium sulphate

54 grams of Magnesium in the form of magnesium sulphate for the plots.

Week 2 12th October 2016Spear Grass responded to the rainfall with 100mm growth on average and greener tiller colour. It was noted the Mediterranean Snail was in some of the plants from plots A and C causing minor damage to immature seed stalks.Wallaby Grass responded to the rain with a definite darker leaf and some new soft leafed tiller growth. Weeping grass also had Mediterranean Snail living in some of the plants. Some of the tillers showed signs of effect to the weather.

The decision was made to reduce the height of the middle plots of each species to 100mm each week. The first height reduction occurred 5th October 2016. It was noted that more than average rainfall was recorded - approximately 40mm over 3 days in the week. Temperatures had increased in the past fortnight to 20 degrees Celsius, a few more degrees than August to September averages.

Week 3 19th October 2016Spear Grass Plot B responded to the height reduction with definitely noticeable greener tiller colour than the plots A and C. It was noted the Mediterranean Snail activity had increased.Wallaby Grass lost colour and in particular the margins of the leaf are yellowing. Weeping grass has started to produce seed in the majority of plants.

Week 4 26th October 2016Spear Grass plants showing seed stalks stripped bare. Spear grass in full seed production and all plants were back in seed within a week of height reduction. Seed is light in colour, possibly ready to set. Mediterranean Snail activity is significant in Plots A and C.Wallaby Grass is yellowing along the margin of the leaf. Plot B has a darker lime colour after the reduction. Wallaby grass is starting to produce some seed.Weeping grass is in seed production and some plants are already dropping seed. Some plants have lightened in colour, a possible response to the weather pattern and energy required from seed production. Some older tillers have died off, giving the overall plant a lighter appearance. Width measurements have been recorded against the seed and also the crown.

Week 5 2nd November 2016Spear Grass has a healthier appearance in Plot B and is a deep green colour. Plants from plot B return to seed production within a week. Plot C plants are in seed production.Wallaby Grass has a significant stressed appearance after the hot weather.

Weeping grass has a similar appearance to the previous week.

EPAN reading reaching 7mm according to Bureau of Metrology website. An official response to this was to start irrigation 2/11/2016 with 10mm applied over 10 minutes.

Irrigation readings 11197.1L 9/11/2016 and then 11376.0L 9/11/2016 after 10 minutes11444.3L 16/11/2016 11461.0L 23/11/2016

Week 6 9th November 2016 Spear grass - Plot 3 light colour of the seeds suggesting that they are ready to drop.Wallaby grass – Some plants producing seedWeeping grass – Dropping some seed. Some plants have lightened in colour, a possible response to the weather pattern.

Week 7 16th November 2016Spear grass - Plots A and C seed heads have lightened in colour. Plants in the immediate vicinity of the reticulation had a greener appearance. Spear grass colour has deepened in the stems rather than leafs. Mediterranean snail not visible on the Spear grass.Wallaby grass – had darkened in colour, however some plants still showing discolouration along the margins of the leaf. Mediterranean snail has moved to some of the Wallaby grass plants.Weeping grass – has improved in health as a reaction to the water application. The plant colour has changed from a lighter green to a darker green within a week. The grasses from plots A and C were blocking the reticulation and so 450mm and 600mm risers were installed to compensate. An application of fertiliser was applied at a rate of 400kg/ha equivalent to 1.44kg per plot.

Week 8 23rd November 2016 (Final Check)Spear grass – Some plants have evidence of snail attack as stems are snapped. Seed heads are golden. No plants have died since first measurements were observedWallaby grass has slightly improved in colour which can be described as lime green. The seed heads have become fluffy and about a dozen have snapped off in whole. Margin yellowing is only slight and hardly noticeable. The 2nd plot looks the healthiest overall and has a darker green colour then Plot 1. Plot 3 has been the worst performing plot of the Wallaby grass and nearly ½ the plants in that plot are either dead or poor height, width and colour. This is compared to 2 plants dead in Plot 1 and 2 plants showing poor height width and colour. Plot 2 produced 2 plants that had poor height, width and colour and the other 23 plants growing well.Weeping grass has shown little reaction to the nutrients applied the week before. The plants growing in plots A and C are now well into seed production. As a result, the plants from these 2 plots have a large proportion of dead tillers, degrading the appearance. Plot B has significantly improved performance compared to the plants that were left to seed. A darker colour and a smaller amount of dead tillers amongst the green tillers.

Graphs

The graphs show the average measurements of the height and widths of each of the 3 species of native grasses from the 8-week Trial 2. Plot A and C include the averages of 10 plants while Plot B included the averages of 5 plants.Spear Grass

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References

WebsitesCSIRO 1998, Mediterranean snails, CSIRO, viewed 1 November 2016, http://www.ento.csiro.au/biocontrol/snails.html

BooksPaterson J.G 1992, Grasses in South Western Australia, pp 45, 65 and 96-97, Department of Agriculture, Western Australia.

Powells J and Pope L 2013, Grasses of the NSW tablelands, pp 77, 120 and 138, Department of Primary Industries, State of New South Wales.

Kerruish R.M and Unger P.W 2010, Plant Protection Pests, Diseases and Weeds, 4th Edn, pp 293-306 , 395 Rootrot Press, ACT

Quinn, J. (2000). Adaptive plasticity in reproduction and reproductive systems of grasses. In Jacobs, S., & Everett, J. (Eds.), Grasses: Systematics and Evolution (pp 281-286). New Brunswick, NJ USA: Department of Ecology, Evolution and Natural Resources, Rutgers University.

Clarke I 2015, Name those grasses Identifying Grasses, Sedges and Rushes, pp 204-217, Royal botanical gardens, Victoria.

Kenneth Horst R, 1979, Westcott’s Plant Disease Handbook, 4th Edn, pp 126, 220, 284, Litton Educational Publishing, Inc, USA

Paul Colman (2009). All U Need. On History [CD]. Australia: In Pop Records

http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_display_type=dataDGraph&p_stn_num=009172&p_nccObsCode=122&p_month=11&p_startYear=2016