A D D I N G VA L U E T O T H E B U S I N E S S O F C R O P P I N G

Foundation for Arable Research PO Box 23133

Hornby Christchurch 8441

Phone: 64 3 345 5783

Fax: 64 3 341 7061 Visit: www.far.org.nz

From the Ground Up ISSN 2324-1411 (Print)

ISSN 2324-142X (Online)

A D D I N G V A L U E T O T H E B U S I N E S S O F C R O P P I N G

From the Ground UpISSUE 99 I SPRING 2019

™

In this issue:• Which nitrogen

test?

• Soil quality

• Herbicide resistance

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We’re here to helpFarmers, industry groups and rural advocates have had a busy few months getting their heads around a range of issues relating to potential changes in land, water and climate regulation.

In September, the Action for Healthy Waterways discussion document set off a round of very well attended meetings, while October’s announcement that agriculture is unlikely to join the Emissions Trading Scheme, but instead work with the Government to reduce emissions, has ignited further debate.

So, what does it all mean? While the details remain sketchy, the big picture is very clear. All land-users, be they arable, pastoral or horticultural, are being asked to manage their systems in such a way that impacts on soil, water and climate are as low as possible. Again, I hear you ask, “so, what does that mean and how do I do it?”.

It’s about identifying and adopting, as well as demonstrating and recording good management practices (GMP). A lot of this comes down to measuring and monitoring, and this means record keeping. Think ProductionWise® here. It’s also about being efficient with all inputs; in the USA they talk about the 4Rs. • Right product• Right quantity• Right time• Right place

A GMP approach to nutrient management involves soil testing, understanding how much nitrogen the crop will require to reach yield potential, and then applying the correct amount. Because nitrogen is the biggest contributor to greenhouse gas emissions from arable farms, getting this right will earn you three big ticks…one for cost savings, one for reducing the crop’s N leaching potential and one for reducing its greenhouse gas emissions. Similar GMP approaches to efficient irrigation and agrichemical use will also provide compliance dividends.

FAR understands that the constant influx of rules and regulations is frustrating and confusing, but we are also confident that the arable industry has the skills, knowledge and flexibility to adapt. We are currently working on a new knowledge exchange plan that will pull together the results of many different research projects and tailor them to match the compliance requirements of growers in different zones, regions or catchments.

Demands around compliance, especially environmental compliance, are not going away, they’re not all easy to meet, but they are not all impossible either. Any step towards input efficiency is a good one. We’re here to help, so please, keep in touch.

Anna Heslop

ContentsThis Issue

3 We’re here to help

4 Back to the future with crops and stock

5 A word from the Chairman

6 Cereals research update

8 Cocksfoot seed production research

9 Mini visual soil assessment (miniVSA)

10 Is Precision Agriculture for you?

11 FAR notices

12 Alternaria on cereal seed imports - why all the fuss?

14 Nitrogen 101

16 Arable monitor farm nutrientuseefficiency

17 ProductionWise®

18 Herbicide resistance research update

19 Hola y adiós Argentina

20 Coming to terms with glyphosate risk

23 Expanding across the high yielding zones

24 ARIA 2019

25 NCRSfieldday2019

26 Good management practices for setback strips on cropping farms

27 FAR Board

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Back to the future with crops and stock

climate, so ‘new’ systems would have to be more diverse and optimise the benefits of both livestock and crops. At the farm level, this could mean specialised business units with no organisational integration, a single business unit with separate activities, spatially intergrated rotational activities, or even more sophisticated synchronised activities that are integrated both spatially and temporally on the farm. Each grower could choose what works best for them.

We know that mixed cropping and livestock systems can improve nutrient cycling, reduce soil erosion, improve water conservation, increase biodiversity and soil quality and thus, the resilience to cope with climate change induced hazards. We also know that, if managed well, such systems can deliver productivity benefits, for example high stocking rates via the provision of quality animal feed at critical times of the season, cost savings associated with the use of animal fertiliser to enhance soil and crop quality, the use of crop residues for animal bedding etc.

The increased complexity of such systems is likely to require additional labour, infrastructure and technical and business skills, but will also provide growers with diverse income sources and a level of long-term resilience and sustainability that is currently lacking. And while the individual performance of each component of a mixed farm enterprise may not be as good as it would be in a specialised system, at the whole farm level, economic performance can be as good as a specialised farm.

Arable growers already successfully manage diverse cropping systems and many already operate some form of mixed farming system. Our top performing growers are highly profitable because they have learnt how to integrate different types of farm activities in a way that not only makes good financial sense, but also provides a resilient and sustainable farm business. They are exemplars of what the government wants from the New Zealand farming sector, namely profitable businesses producing quality food products in an environmentally sustainable way. We should be promoting them as leaders in New Zealand’s transition to a more diversified and resilient agro-economy.

It is time for leading growers to take the lead – watch this space.

Alison Stewart, CEO

We are being inundated with media commentary around the negative impacts of livestock farming on everything from water quality and greenhouse gas emissions to human health. We are also being told that the future is all about plants…for milk, for protein, for better health and a better environment.

This sounds great but let’s not get carried away. The plant picture is likely not as rosy as many people make out. Land suitability constraints, commodity prices, taste and nutrition are all potential issues, and New Zealand’s perverse land prices and associated farmer debt levels would also compromise a wholesale transition from animal to plant based agri-systems.

For me, the big question around all of this is, why would we want to go down this track? Why does it have to be an either / or situation? Why can’t New Zealand embrace both plant and animal production, and get the best of both worlds?

Intensive monoculture systems create efficiencies of scale and drive productivity and ultimately profitability; but they also have negative effects, particularly on the environment, and rectifying these environmental effects comes at a substantial financial cost. Monocultures are also vulnerable to risks such as the loss of significant markets (think wool) and biosecurity incursions (think Psa or M. bovis). Such risks should not be countenanced in a country such as New Zealand that is so reliant on its primary sector. In my view, it really doesn’t make sense for New Zealand to transition out of intensive dairying to intensive horticulture or intensive cropping, or any other form of intensive agricultural activity.

Common sense tells us that New Zealand has to diversify its farming systems, either within farms, between farm systems or across a landscape. For arable growers, this could be as simple as adding new crops into the existing rotation or looking at multiple cropping or intercropping systems. Successful overseas examples of these latter options, include lucerne and canola in Canada and the classic three sisters system (maize, bean and cucurbits) in the United States; both of which provide benefits such as increased overall productivity, improved nutrient balances, weed suppression and space savings.

Perhaps New Zealand should move forward by reverting back to a mixed farming system. The mixed systems of the 70s and 80s wouldn’t be profitable enough in today’s economic

A word from the Chairman

The Fresh Water Reform proposal is trickier. I hope that, despite the limited time available, many of you made submissions on the effects as you see them. FAR has helped with information for the Federated Farmers submission, and has made a separate arable industry submission.

Growers would all agree that meeting the load limits of our catchments is an appropriate target. It’s the how and how fast that is critical. We need tools to accurately assess catchment load limit, rather than across the board numbers. Similarly, the capacity of Overseer to accurately assess actual farm output is critical to make appropriate management decisions and understand how actions convert to individual contribution to DIN limits. Again, FAR is committed to helping identify appropriate tools and farm practices to meet these challenges. It is also noteworthy that as part of this proposed policy there is a change to priority of water use. Commercial water will now rank 3 behind human and environmental use, even though community is meant to make those priority decisions but if the decision-making framework changes then so do the decisions. Lastly, the time frame and industry capability to deliver these changes would be impossible.

All speed to a successful spring plant and I am not aware of any more unwelcome fronts on the way. The board and I are committed to providing the solutions needed to meet these challenges.

Hugh Ritchie

With the spring planting in full swing, interruptions are unwelcome. Climate ones at least provide some moisture if needed, but others, such as carbon neutral or freshwater management create more uncertainty and stress in an already stressful time.

The announcement of the government / industry He Waka Eke Noa (the Primary Sector Climate Change Commitment) was welcomed by the sector. This enables all sectors to create practical, effective and cost-effective responses to the goal of keeping temperature rises to under 1.5 degrees. This has seen a major change of approach from the government as a result of industry engagement. It also needed some hard negotiating within the sectors to reach a workable solution. Thanks to Alison and the other CEOs who worked to develop this outcome.

Two points to make: first, by working across sector we can with a unified voice influence legislation that will affect our industries; and second, to maintain the confidence of government we need to hold up our part of the agreement. FAR will need to consider solutions for problems around how to measure and what offsets can be used for the main emitters (fertiliser and chemicals). This work has already started and will intensify as we move forward, but at the end of the day, all growers are going to need to implement these solutions so we deliver on our commitment. The work for us all has just begun.

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BYDV management The MPI Sustainable Farming Fund (SFF) project, Improving BYDV Management, was granted a one

year extension to validate field results from 2018 trials. Shade house work

in the first two years indicated there was a potential yield loss in wheat crops from BYDV infection up to the end of stem extension. This year’s trials are repeating this proof of concept to the field in two autumn sown wheat crops. The trial is using full tramlines for the four treatments, which include protecting the crop to the start and end of stem extension, an integrated pest management and seed treatment. The weigh wagon will be used to measure grain weight of each treatment at harvest.

RamulariaAnother SFF project, Improving Ramularia management in barley crops, is also underway. Early

results from testing Ramularia isolates collected from barley crops in

Canterbury, Manawatu and Southland in 2017-18 indicate that there has been a further shift in insensitivity to SDHI fungicides, with more than 96% of isolates collected insensitive. This laboratory testing aligns with observation in the field that SDHI and triazole fungicides are now less effective at controlling Ramularia. Other parts of the project investigate the role of seed borne Ramularia, effective fungicide programmes and barley cultivar resistance ratings. FAR trials have shown the new multisite fungicide Phoenix® has shown good control of Ramularia when used in a mix with Proline®, although this combination is weak on leaf rust. Currently, Phoenix has a registration for control of Ramularia up to GS39. FAR trials in 2019 will investigate the value of Phoenix and what role, if any, SDHI fungicides now have in autumn and spring sown barley disease management programmes.

Septoria Research from the United Kingdom has indicated a sensitivity shift to SDHI fungicides, however laboratory

testing by Plant & Food Research shows that Septoria is still sensitive to

SDHI fungicides in New Zealand. Wheat disease management research further explores whether fungicide programmes can be reduced with higher cultivar disease resistance. Results from cultivar x fungicide programme trials in 2018 found less yield loss for the moderately resistant cultivar Reflection compared with the cultivars Graham (moderately resistant) and Conqueror

Cereals research update

(moderately susceptible). As well as lowering input costs, this approach would contribute to resistance management by, for example, only using one SDHI fungicide in a crop. FAR is reviewing its cereal disease management strategies to focus on optimising the number of fungicide applications and dosage that leads to effective disease control and maximising returns whilst prolonging the effective life of the fungicide.

20 tonnes by 2020The 20 by 2020 high wheat yield programme is in its final season of field trials. The research is

screening germplasm provided by seed companies which is adapted to

an early sow date. The work includes four selected cultivars from last year’s trials with advantages over the cultivar Wakanui. These cultivars, together with Wakanui, are being tested in a sow date trial with March and April sow dates. These trials are being run at Leeston and Wakanui.

Nitrogen in milling wheatFAR conducted a series of milling wheat N response trials in the 2000s to help provide N

application guidelines to famers. The cultivars used, Amarok and

Conquest have become less commercially popular since then. In 2019 a trial has been established at Chertsey investigating optimal nitrogen management in two current commercial milling wheat cultivars, Griffin and Discovery, under irrigated and dryland conditions. Griffin is a premium grade milling wheat and Discovery is a medium grade cultivar.

Grain storage pestsThe recently completed SFF project Understanding and Managing Pests of Stored Grain

developed two bioassay methods for testing efficacy of pirimiphos-

methyl (the main grain protectant insecticide registered in New Zealand). The mini silo and micro plate bioassays on sawtoothed grain beetles collected in Canterbury identified populations with different responses to pirimiphos-methyl. The testing is relatively quick; results can be obtained in 48 hours for a mini silo and 24 hours for a micro plate bioassay. The limiting factor is having sufficient insects to treat.

The cereal research season is well and truly underway, with a strong focus on weed, pest and disease management. Cereal researcher Jo Drummond outlines some of the current projects.

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Cocksfoot seed production research

Unlike ryegrass, cocksfoot seed heads are formed on tillers that are formed in autumn, so autumn management, especially N inputs, can be important. The required rate of spring N has been the focus of a series of on-farm trials, and results to-date suggest that cocksfoot seed crops require only a modest amount of spring N: a combined soil mineral N + applied N of 160-170 kg N/ha. In 2019/20 N-rate trials are continuing at two locations, Wakanui and Methven.

Results to-date suggest that cocksfoot seed crops require only a modest amount of spring N: a combined soil mineral N + applied N of 160-170 kg N/ha.

With many cocksfoot cultivars now in production, another important question is whether those cultivars all have the same herbicide tolerances. An 11-cultivar trial was sown at Chertsey in autumn 2018 to assess 19 herbicides at establishment and was used this year to measure for tolerance to residual and wild oat herbicides. Water use and irrigation requirements of cocksfoot seed crops are also being assessed at Chertsey with seven watering regimes to create different levels of water stress.

Phil Rolston

Cocksfoot is now the second largest grass seed crop after ryegrass grown in New Zealand.

With the formation of the Seed Industry Research Centre (SIRC) in 2017, a priority research area was to increase the research effort around cocksfoot seed production. Oregon, USA has been the traditional major international producer of cocksfoot seed, but choke disease caused by Epichloë typhina has had a major impact on production area and crop yields, resulting in an increase in New Zealand production.

As part of collaboration between Oregon and FAR, a study of cocksfoot seed crop responses to plant growth regulators (PGR) and nitrogen (N) rates was initiated. This work built on previous studies by SIRC members PGG Wrightson Seeds (Murray Kelly) and FAR on PGR responses.

As New Zealand growers adopted recommendations to apply a mixture of two active PGR ingredients, dryland farmers around Methven reported concerns about severe leaf burn which they thought was causing yield reductions. Part of the current cocksfoot research programme at FAR’s Chertsey site is attempting to re-create PGR leaf-burn and determine its impact on seed yield. Last year’s spring was wet and cool so there was minimal leaf burn, however, a large PGR seed yield response was associated with reduced lodging and stem shortening.

Mini visual soil assessment (miniVSA) New Zealand’s primary sector economy is dependent on productive and resilient soils. The last two decades have seen significant changes to the management of arable crop production systems in New Zealand. Some changes are likely to have led to an improvement in soil quality, while others may have had adverse effects. Intensive and non-restorative practices (i.e. limited amounts of organic matter are returned to the soil) are likely to reduce soil quality and increase the risk that soil conditions will limit crop productivity and cause adverse environmental impacts. Increasing a soil’s organic matter (SOM), which is on average made up of around 58% carbon, will benefit soil structure and improve aeration, root development, water infiltration and storage. SOM is also important for earthworms and other soil fauna.

Although no two cropping rotations are the same, mixed arable farms tend to return more organic matter to the soil due to the restorative pasture phase. This is more apparent in Southland, where the mixed arable rotations typically include longer duration grass leys than other regions e.g. Canterbury (Figure 1).

Figure 1. Total soil organic carbon % (0-15 cm) for Canterbury and Southland sites. The box represents the middle 50% of stabilities, while whiskers represent the 10th and 90th quantiles. The line inside each box is the median value. The shaded green area represents recommended ranges. (Establishing a Soil Quality Benchmark for the Arable Sector, Plant & Food Research 2019).

Understanding the risk posed to soils by arable systems is important, as is the ability to assess and quantify changes in arable soil quality and resilience. With this in mind, FAR has developed a simple soil quality ‘mini’ visual soil assessment for cropping farmers. This miniVSA has been adapted from Plant & Food Research’s Soil Quality Management Assessment (SQMS), the UK Soil Management Initiative’s Visual Soil Assessment and Manaaki Whenua - Landcare Research’s visual soil assessment field guide. It involves three quick tests on: 1. Structure and porosity2. Turbidity3. Earthworm numbers

Good soil structure provides greater resistance to compaction and maintains the soil porosity necessary for roots to access air, water and nutrients. The structure and porosity and turbidity scores assess the structure and stability of soil aggregates, while earthworms are an important biological indicator. Through their feeding and burrowing activities, earthworm can enhance nutrient availability, increase the movement of air and water, and improve the structural condition and stability of soils.

Regular soil quality assessments can assist with:• Understanding the full impact of prior management decisions.• Identifying constraints to production.• Selecting and implementing future management strategies

that will improve soil quality and are feasible for your operation.• Measuring progress and adjusting management appropriately.• Providing evidence of good soil management practices to

support FEP audits.

Abie Horrocks

Information on how to carry out a miniVSA, including a scoring sheet and demonstration video, is available in the Resources section of the FAR website - search soil. Scores for each of the three tests are recorded on a score sheet; they are likely to fluctuate as the rotation transitions through depletive and restorative phases and allow overall trends to be tracked over time.

Carbon % (0-15 cm) 1 2 3 4 5 6

Carbon % (0-15 cm) 1 2 3 4 5 6

CanterburyContinuous arable

Mixed arable

SouthlandContinuous arable

Mixed arable

Poor condition Good condition

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Where possible remedy any underlying site issues before undertaking other site-specific crop management tools. Remedies could include reducing surface water ponding by drainage, deep ripping compacted areas or managing soil pH variation by variable rate lime application.

Site-specificcropmanagementSite-specific crop management involves matching crop inputs to the yield potential of the site. For example, Paddock A has an average wheat grain yield of 14t/ha, with some areas yielding 18t/ha, and others only 10t/ha, but the whole of Paddock A receives the same inputs. Identifying the high and low yielding zones is the first step in managing the variability of the site, and ultimately undertaking site specific crop management through techniques such as variable rate seeding, nutrient application or irrigation to match the expected yield potential for each of the zones.

Site-specific crop management can also be thought of as a series of layers of information for each paddock. Each time a measurement is made (soil tests, scouting reports, yield data, etc), another layer of information is added. Over time, multiple layers of information are added and become part of the database that can guide future crop management decisions. By geo-referencing each data point, the relationship between layers for any point in the field can be investigated. For example, the relationship between nitrogen rate applied and yield obtained might be determined, and then its variability mapped as an additional “calculated” layer of information.

NoticesFAR Annual General Meeting The FAR AGM will be held: 6.30 pm , Wednesday 4 December 2019 Hotel Ashburton, Racecourse Road, Ashburton.If you have items of general business related to the AGM, pleasenotifytheFARofficebeforethemeeting.Anyarablecrop grower who has paid an arable crop payment or filledoutaFARAnnualReturnFormiswelcometoattend.Please RSVP your attendance by Friday 29 November to melanie.bond@far.org.nz

Arable Crops LevyPursuant to section 4 of the Commodity Levies (Arable Crops) Order 2018 (“Order”), a levy has been imposed on, and shall be payable by, the producers of any arable commodity grown in New Zealand.In accordance with section 14 of the Order, the Foundation for Arable Research Incorporated has determined the levy rates for 1 January 2020 to 31 December 2020 will remain unchanged at:Herbage and amenity seed – 0.9% of sale value.All other grain and seed crops (cereals, pulses etc) – 0.9% of sale value.Open pollinated vegetable seed crops – 0.9% of sale value.Hybrid vegetable seed crops – 0.6% of sale value.Dated this 13th day of September 2019.A. STEWART, Chief Executive Foundation for Arable Research Incorporated. Contact Details: PO Box 23133, Hornby, Christchurch 8441.

Maize LevyPursuant to section 4 of the Commodity Levies (Maize) Order 2018, a levy has been imposed on, and shall be payable by, the growers of any maize seed sold for sowing.In accordance with section 11 of the order, the Foundation for Arable Research Incorporated has determined the rate of the levy for July 2019 to June 2020 to be:Maize – $1.00 per 10,000 seeds.Dated this 15th day of March 2019.A. STEWART, Chief Executive Foundation for Arable Research Incorporated. Contact Details: PO Box 23133, Hornby, Christchurch 8441.

Cereal Silage LevyPursuant to section 4 of the Commodity Levies (Cereal Silage) Order 2018 (“Order”), a levy has been imposed on, and shall be payable by, the producers of any cereal silage commodity grown in New Zealand.In accordance with section 13 of the Order, the Foundation for Arable Research Incorporated has determined the levy rates for 1 January 2020 to 31 December 2020 will remain unchanged at $10.00 per hectare harvested.Dated this 13th day of September 2019.A. STEWART, Chief Executive Foundation for Arable Research Incorporated. Contact Details: PO Box 23133, Hornby 8441.

Is Precision Agriculture for you?

or software packages you use, ii) avoid getting bogged down in detail – if you have a 12 m fertiliser spreader the smallest area you can change application rates for is 12 m wide, and iii) ground-truth (validate) any data recorded to ensure it accurately reflects reality.

Mapping variability Management zones are areas within a paddock which have similar characteristics, and can be managed in a similar way. There are high and low-tech ways to measure and map these zones. High-tech methods quantify the growing environment by collecting soil data using grid sampling or on-the-go sensors, while a low-tech approach is a simple farm outline map where any areas of paddocks that are consistently high or low yielding, high yielding in wet or dry years, etc, are drawn in, shaded and labelled. Either way, the result is a map with production information and an easy-to-view colour classification. Geospatial data from yield monitors or sensors can be included on a hand drawn zone map and research has found that management zone (MZ) maps hand drawn by experienced farmers closely correlate with high-tech MZ maps generated from multi-year yield, soil and other data.

Whatever method you use to assess the variability in your paddock, it is essential to ground truth it by walking the paddock and digging holes to confirm differences in the soil. Once you have identified the zones and ground-truthed them, identify any relationships between the growing environment and yield maps. If you have low yielding areas, identify and correct the limiting factor or reduce yield target and inputs. If you have high yielding areas, assess the potential for increasing yield by increasing inputs.

Precision Agriculture (PA) is a blanket term covering many different technologies which can help identify and manage land and crop variability. Some PA technologies have been around for decades, while others are new and unproven. Well implemented PA can reduce the risk associated with farming and maximise gross margin, while poorly implemented PA may incur significant costs for little, if any reward.

Most New Zealand arable growers use at least one PA tool or technology, for example machinery autosteer, or section control on a planter or sprayer, at some stage of the cropping cycle. Other common uses include variable rate application of seed, nutrients and water; sensors to monitor soil and crop conditions or the collection of high-quality yield data at harvest.

The range of PA technologies can seem overwhelming. Marketing efforts focus on providing tempting offers to make your operation easier and more profitable, but, disappointingly, PA technologies have a track record of over promising and under delivering.

So how much, if any, effort and investment should you put into Precision Agriculture for your farm?

How far you choose to go with PA is up to you, but it makes sense to use some fundamental technologies to their full potential before investigating new ones and to make your PA system as simple as possible. Four fundamental technologies are i) autosteer, ii) section control, iii) yield monitoring and iv) gross margin mapping; while the following rules will help keep things simple…make sure you i) minimise the number of apps

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Untreated seeds contaminated with Alternaria above and infected seeds treated with Kinto Duo below. Alternaria are the dark colonies (courtesy Mark Braithwaite, Plant Diagnostics).

Fungicides to reduce Alternaria on imported seedA number of seed treatments were also tested on seed lines known to contain Alternaria species and other potentially important pathogenic species such as Drechslera, Stemphylium, Gerlachia and Fusarium. Two treatments, Systiva® (SDHI fluxapyroxad) and Kinto® Duo (a mix of the triazoles triticonazole and prochloraz), were effective at controlling Alternaria and snow mould (Gerlachia) infections, suggesting that these fungicides could be successfully used as a treatment option for imported seed-lines to control undescribed Alternaria spp. including those in Section Infectoriae.

De-regulation In early August, based on the supporting evidence provided by the collaborative initiative outlined above, MPI’s Chief Technical Officer announced the de-regulation of undescribed species of Alternaria in the A. arborescens and A. infectoria species complexes on the oat, wheat, barley and Lolium seed for sowing pathways. As a result of this decision, we anticipated less disruption on this import pathway. This has proven to be the case to an extent, but interceptions have continued as MPI seek to ensure other undescribed species of Alternaria do not enter the country. How we resolve this situation is unclear, but it is in our interests to try to ensure healthy seed is crossing our border.

AcknowlegmentsFAR would like to acknowledge Mark Braithwaite and colleagues at Plant Diagnostics Limited, Ian Harvey at Plantwise Limited & Simon Bulman & Soonie Chng at Plant & Food Research for conducting the research and the Seed Industry Research Centre for funding.

For further information please contact Andy Pitman at andrew.pitman@far.org.nz or call on 027 252 5722

Alternaria on cereal seed imports - why all the fuss?

We’re still unsure if the increased detections are due to increased numbers of seed consignments with black point-like symptoms, or if there has been a change in how visual inspections are conducted by MPI. But given that the seed-for-sowing pathway is a relatively high-risk one for invasive organisms (eg infected kiwifruit pollen), it is safe to assume MPI has become increasingly cautious.

What we do know is that MPI border screening of seeds with black point-like symptoms has identified a range of fungi present on the seed, including Alternaria alternata and numerous other undescribed species of Alternaria. Although Alternaria alternata is not on MPI’s hit list, undescribed species of Alternaria have until recently been regulated, meaning that any contaminated seeds must be given a ‘return or destroy notification’ or control measures put in place for their release.

Alternaria spp. are recognised as plant pathogens across a wide range of plant hosts and have caused significant impacts on New Zealand sectors in the past, so they are a genuine threat. But on the flip side of the coin, many Alternaria species are considered non-pathogenic to plants, the cause of black point disease has long been highly contested, and there is a strong likelihood that undescribed species of Alternaria have been present on cereals in New Zealand since at least the 1980s.

What’s new with Alternaria in New Zealand? In an attempt to reduce border interceptions, a collaborative initiative between industry and MPI was set up to clarify the presence of undescribed species of Alternaria on cereals in New Zealand and remove their regulated status. Cereal seeds from three New Zealand sources were tested for the presence of Alternaria spp. Two of these were of grain from recent harvests (2016 – 2018; 55 lines) while one was of grain harvested between 1988 and 1997 (12 lines). Sixty six percent of the grain lines from the recently harvested cereal seed lines yielded Alternaria spp. and they were also detected in the pre-1998 seed lines. Of the 91 Alternaria cultures tested further, 19% were identified as Alternaria alternata and 65% were deemed to belong to the Alternaria clade – Section Infectoriae. In short, this group of fungi has been on cereals in New Zealand for some time.

Over the last 18 months, many New Zealand cereal seed importers have had consignments held up at the border due to the increased Ministry for Primary Industries (MPI) detection of black point-like symptoms or other fungal infections. This has had importers somewhat perplexed, as black point has been present in New Zealand for some time and is considered a low-grade and managed risk to production of cereals in the field. So, what is causing the increased incidence of black point-like symptoms and why has it cast a spotlight on cereal seed imports?

Symptoms on cereal seeds intercepted at the border (courtesy of Ian Harvey, PLANTwise).

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Organic nitrogen: The majority (97-99%) of nitrogen in the soil is present as organic nitrogen and most of this is locked up in the soil organic matter and unavailable for plant uptake.

Mineral nitrogen: Soluble (or immediately plant available) nitrogen comprises only 1-3% of the total soil nitrogen and exists as ammonium or nitrate ions (ammonium-N (NH4+) or nitrate-N(NO3-)). Nitrate is very mobile and is constantly being ‘taken up’ by plants and converted to protein, or is lost by leaching. Ammonium is rapidly converted by soil microbes to nitrate (when soil temperatures allow).

Mineralisable nitrogen: Organic nitrogen is converted to mineral forms through the decomposition of soil organic matter by soil microbes in a process referred to as ‘mineralisation’. Mineralisable nitrogen is the fraction of the organic N that is mineralised over the growing season and can become available to plants.

Nitrogen 101Effectiveuseofnitrogen(N)isattheheartofgoodcropmanagement. In the last few months many farmers have taken soil tests in order to estimate how much nitrogen fertiliser should be applied to supplement soil N and maximise returns.

Why use nitrogen fertilisers? Plants produce saleable yield through capturing solar radiation and converting it into dry matter (yield) through the process of photosynthesis. Yield is related to the total amount of solar radiation captured and utilised during the life of a crop. To capture solar radiation, crops produce leaves in the form of a canopy. Nitrogen is critical in determining leaf expansion rate and final leaf size, thus influencing time to row closure. Nitrogen, along with other factors, notably water availability, is also critical in determining how long a canopy stays green at the end of the season (critical for producing grain and capturing large amounts of solar radiation).

Unless legumes are included in the crop rotation or large amounts of organic matter can be mineralised, soils often cannot supply enough spring or summer nitrogen because plant uptake and environmental losses exceed mineralisation rates. Good farming practice requires tailored nitrogen fertiliser programmes that match nitrogen supply to the crop demand. Such programmes provide both economic and environmental benefits to the farm by optimising crop production whilst saving money on inputs and conserving energy through the application of the right amount of fertiliser, in the right place at the right time.

The impacts of N deficiency can often be all too obvious

Figure 1. Typical soil nitrogen ratios.

However, with numerous soil nitrogen tests available and many commercial providers using different terminology or reporting templates, knowing what to test for, and how to interpret the test results, can be confusing. Our research team thought that a Nitrogen 101 might be useful as a refresher.

What forms of nitrogen are in the soil? New Zealand top soils typically show that up to 5000 kg of N per hectare is present.

1-3%Mineral N

97-99%Organic N

A soil mineral N test provides the N that is immediately plant available as ammonium and nitrate. The results obtained from the soil mineral N test are usually given in mg/kg (interchangeable with µg/g or ppm).

A number of commercial providers provide AMN or Mineral N tests.

Alternatively, you could try the ‘Quick N’ test for a speedy and economic turn-around of mineral N results. The quick test is a method that rapidly measures the nitrate concentration in a soil. It costs about $2.00 a test, but there is an up-front cost to get kitted out. Quick N test kits can be ordered on line from www.labsupply.co.nz and an information book outlining how to use them is available from the Resources section of the FAR website www.far.org.nz. All of these tests have value, but Mineral N values are predominantly used to estimate immediate crop N fertiliser needs.

How can I use my soil nitrogen results to estimate fertiliser needs?The results of soil N testing can be used to manually calculate the amount of fertiliser to apply. They can also be input into decision support tools to help calculate fertiliser application. For instance, we have recently released a new version of AmaizeN that can help maize growers with their decisions on fertiliser applications. This too, can be found in the Resources section of the FAR website. The instructions with AmaizeN give you all the information you need, but it is important to remember that this software requires the input of mineral N test results, not AMN results.

The AmaizeN tool calculates the soil supply of N from your soil test results and the potential crop yield. It then predicts how much fertiliser N you will need to add to reach the crop’s potential yield or most economic yield. Potential and economic yields are different and you will need to decide on the one that best suits the way you manage your farm system.

How and when should I prepare a sample? Detailed protocols on soil sample preparation are included in the AmaizeN instructions on the FAR website. Some key points to remember are:1. Collect your soil sample as close to the time you will be

making fertiliser decisions as possible to know what N is immediately available.

2. Sample down to at least 30 cm, if not more, so as to establish how much N will be available in the root zone.

3. Chill your soil sample to reduce mineralisation during transport. Our research team freeze samples if they cannot be extracted immediately (this provides comparable results from long term data). You will see the test report states the temperature of the sample on arrival, so it is clearly important.

4. It is unlikely that N levels will stay the same from one season to another since seasonal climatic differences, farming practices and crop removal will affect residual soil N levels and the ability of the soil to provide plant available N.

Andrew Pitman

Why do a soil nitrogen test? A so called ‘N mass balance budget’ is an efficient way to determine how much nitrogen fertiliser should be applied to the crop to achieve a crop’s potential yield. The development of this budget requires estimates of how much nitrogen the crop will need and how much nitrogen will be supplied by the soil or by fertiliser. Estimating the soil nitrogen supply depends on soil testing.

To meet current Farm Environment Plan auditing standards, fertiliser applications need to be paired with decision support tools such as appropriate soil testing.

What soil nitrogen should I test for? The common test to measure mineralisable nitrogen is to incubate the soil sample at a warm temperature to accelerate the rate of conversion of organic matter N to ammonium-N as described above. The test is either called anaerobically mineralisable N (AMN), potentially available N or available N (and will be reported inclusive of mineral N - see below).

Soil analysis results

Sample Name 7 0-30014 Aug 2019

8 300-600 14 Aug 2019

Lab number 2224421.1 2224421.2

Sample type SOIL arable SOIL general, sub soil

Sample type code S56 S147

Volume weight g/mL 1.03 -

Potentially available nitrogen kg/ha (15 cm depth) 119 -

Anaerobically mineralisable N* µg/g 77 -

Ammonium-N* mg/kg 1 <1

Nitrate-N* mg/kg <1 <1

Mineral-N (sum)* mg/kg <2 <2

Dry matter*% 79.7 82.2

Moisture*% 20.3 17.8

Sample temperature on arrival* oC 13 13

Soil sample depth* mm 0-300 300-600

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is helping farmers, here’s how

FAR’s vision for ProductionWise:

“Provide the ProductionWise system as an auditable crop management tool to record accurate financial information for farm systems, to increase farm profitability, provide assistance with environmental stewardship, along with benchmarking reporting, for cropping farmers”.

So we started with the newly developed Training Programme in Canterbury and Southland during August and September. The purpose of these programmes was to upskill farmer’s awareness and knowledge of how the ProductionWise system can be a key tool for environmental compliance and to assist farm profitability. Farmer training days were in the form of ‘round the kitchen table’ type sessions and ‘all day drop-in’ style trainings. These sessions were designed to assist new farmers to get onto the system or to show existing farmers the latest time saving features.

Here’s an example of how the courses were runThe first area was the Fairlie Basin with a ‘round the kitchen table’ training morning at a farmer’s farm. This area is just starting with consents for irrigation so we covered how ProductionWise helps with FEP maps and records and farm planning records, all of which are required for auditing purposes.

In Ashburton we ran an ‘all day drop-in’ style training where we had farmers with different ProductionWise skills making use of the FAR staff on hand to learn either how to start with

ProductionWise or learn how they can get more out of it for farm profitability. We learnt from the farmers how farm budgeting for bank lending, is now on the farmer’s shoulders not bank managers; so we covered how easy it is with just normal day to day crop recording, to create crop gross margin figures to assist with compiling a cash flow budget for a farm cropping year. The cool farmer benchmarking tool in ProductionWise compares all crop gross margins for personal scrutiny.

In Mayfield, we had another great session with farmers. We taught farmers who were new to the system in small groups and one to one training and the more experienced users learnt together around a large computer screen, being more friendly than a power point presentation. One farmer’s experience with the use of the ProductionWise satellite imagery to create variable rate prescription maps and save $’s on nitrogen usage, was shared with the whole group.

Another area of discussion from the Darfield morning, was ‘could the system keep a running calculation of the units of N applied, so that at the end of the season the farmer would know exactly his total N units applied and could he then relate this to his Overseer report’.

The take home message from the training days was that farmers were very positive about having ProductionWise to help them get through audit requirements.

We would like to thank all the farmers for attending our South Island Training Programme and for the assistance some of them gave to others in the sessions and for valuable feedback for future FAR levy investment…… One of the future developments is the possibility of ProductionWise linking to Overseer, which is currently in the early stages.

The next training courses are being planned for the North Island during 2019/2020 and again another round for the South Island during 2020. Please email Melanie Bates, melanie.bates@far.org.nz, if you would like to register for these training sessions in your area or you would like to run one on your farm.

We will be at FAR’s ARIA 2019 event in the South Island on 4 December 2019. We will have a ‘morning tea time’ training session between 9am and 10.30am.

For further information please contact melanie.bates@far.org.nz

www.productionwise.co.nz

ProductionWise is developed by the Foundation for Arable Research. FAR provides ProductionWise crop record keeping and support tools to farmers and their advisers, to help promote efficiency, sustainability and

profitability in modern farming enterprises.

Arable monitor farm nutrient use efficiencyThe Forages for Reduced Nitrogen Leaching research programme, which started in 2013 and was completed earlier this year, targeted differentaspectsoftheNcycleinordertoreduce the risk of nitrate leaching. Monitor farmers, including three Canterbury farms, were an important part of the project, hosting trials and demonstrations of various mitigation optionsidentifiedthroughresearch.

Throughout the life of the programme, a model* was used to quantify nitrate nitrogen (N) leaching in each paddock of the monitor farms. Model estimates indicated that, on average, whole-farm N leaching from the arable farms had decreased by 20 kg N/ha in the last four seasons of the study. Six N leaching risk factors were identified on these farms: 1. Soil N - residual from previous crop and mineralised N.2. Excess fertiliser N - high amounts resulting in substantial

residual soil N.3. Drainage events from high rainfall.4. Timing of fertiliser N application.5. Fallow periods.6. Soil type.

Leaching was mainly influenced by rainfall and soil type, but management practices determined the amount of soil N at risk of loss. Soil N at risk of leaching was mostly associated with excessive nitrogen fertiliser application, mineralisation of N-rich crop residues and extended fallow periods. Similarly, mineralised N from residues retained in paddocks was available for leaching if there was no vegetation to take up water/N and reduce drainage/leaching.

Industry-agreed good management practice is to understand how much nitrogen a crop requires to reach its yield potential, and to ensure that applied fertiliser combined with N from the soil is not greater than that amount. To do this with confidence, farmers require reliable tools. So, as part of the monitor farm study, researchers compared crop performance and N use efficiency following two different nutrient prediction techniques: ‘general practice’ N application rates and APSIM forecasted N fertiliser rates based on deep mineral N sampling and estimated crop yield (provided by the farmer). The crops evaluated were barley and oats. Nutrient use efficiency (grain DM produced

Soil nitrogen (N) testing can make fertiliser N application rates more accurate. Without information on soil N status, too much or too little fertiliser may be applied. This reduces profitandthereisanincreasedriskofnitrateleachingtogroundwater when N supply exceeds crop demand.

per kg of N applied) was improved by 50% in the areas where soil sampling and modelling were used to determine N fertiliser rates compared with ‘general practice’ fertiliser N rates. This knowledge is good news, as greater efficiency in N fertiliser application has three important benefits: reduced costs, reduced nitrate leaching risks and reduced nitrous oxide emissions.

For growers who find the time and costs of carrying out soil tests off-putting, new methods are on the horizon. Quick-N test kits are now available, and a hot water extractable N test, which assesses what N will become available over the growing season, is currently being validated. Together, these tools have the potential to greatly improve N fertiliser rate predictions.

Overall, nutrient use efficiency expressed as a N surplus was very good at the arable monitor farms.

Abie Horrocks

*The model used was the Simple Crop Resource Uptake Model operating within the Agricultural Production Systems sIMulator (SCRUM-APSIM).

When APSIM forecasted N fertiliser rates were used compared to ‘general practice’ N application rates

Nutrient use efficiencyimproved by

50%

NEW ZEALANDSONLINE CROP MANAGEMENT

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1716

Herbicide resistance research update

“The work we are doing now, still using the original plants, which we are able to replicate through tiller division, is aimed at identifying the resistance mechanism in these plants. In Australia, there have been many incidences of resistance where glyphosate will kill plants when it is applied on cool days, but not kill them when temperatures are high. What we are doing now is re-treating the original plants under a range of temperature and dose rates. We hope to have more certainty around what is going on by autumn next year.”

About 20% of the arable farms in Selwyn District were surveyed for herbicide resistance in 2018/19. As well as glyphosate tolerance, the survey also identified Group A and Group B resistance in perennial and annual/Italian ryegrass on a number of the 48 survey properties. The Group A herbicides in question were Twinax (pinoxaden) on six farms and Ignite (haloxyfop-P) on four farms. Group B resistance was identified with Rexade on three farms and Hussar on two farms.

As in Selwyn, the South Canterbury survey will involve the collection of grass weeds from around 30 percent of arable farms in the region with the aim of identifying the presence, or not, of herbicide tolerant weed populations.

Meanwhile, the plants which were identified as tolerant to glyphosate earlier this year remain the focus of weed experts, who are working to understand the levels and mechanisms of tolerance at play. Testing was carried out by AgResearch at Ruakura, and weed team leader Dr Trevor James says that understanding some of the results is challenging.

“In the initial tests, a number of ryegrass plants, from a number of farms, were not killed by glyphosate, while all susceptible plants in the trial control group did die. This confirmed that the plants had a level of tolerance. However, a second round of testing, which involved treating the same plants with several rates of glyphosate in order to identify just how tolerant they were, resulted in all the plants dying. We believe these contradictory results may be due to differences in temperature at the time of application”.

H1 H2

Target

H1

H2

Target

H1 H2

TargetA B C

What are ‘resistance mechanisms’?A weed population is defined as resistant when an herbicide that once controlled the population is no longer effective. This resistance is due to genetic changes (mutations) in the resistant plant. You will often hear reference to ‘target site’ and ‘non-target site’ mutations.

Target site mutations arise due to single mutations in the underlying DNA that change the protein encoded by the DNA (Figure 1). This affects the ability of the herbicide to bind to the plant’s target site. Target site mutations are especially common in weeds with resistance to Group A and Group B herbicides. With target site resistance it is common to get cross-resistance to other herbicides of the same herbicide mode of action.

Non-target site resistance mechanisms allow plants to survive application of the herbicide by not allowing sufficient herbicide to reach the target site. The weed may be initially affected by the herbicide application, but will survive and set seed. The most common example of non-target site resistance is due to increased herbicide detoxification (sometimes called metabolic resistance). With this resistance mechanism, there is more rapid breakdown of the herbicide inside the plant and less of the active herbicide reaches the target site to kill the plant.

Keeping track of herbicide familiesA key tool to reducing the risk of herbicide resistance is to rotate the use of chemical families. Chemical diaries are one way of keeping track of herbicide use, and are a requirement for many grain and seed contracts. However, diaries are crop focused, while herbicide resistance develops in weed populations in specific paddocks.

ProductionWise® is an excellent tool for tracking and reporting on herbicide use in paddocks and can produce a very clear visual report of which chemical families have been used by paddock, and by year, at the touch of a button.

Phil Rolston

Figure 1. Target A has no mutation to the target site so both herbicide 1 and herbicide 2 are able to bind to the target. Target B has a mutation to one side of the target site which prevents herbicide 1 from binding to the target site but does not affect herbicide 2 from binding. Target C has a mutation to the target site which prevents both herbicide 1 and herbicide 2 from binding to the target site. (Adapted from grdc.com.au).

Afarmsurveywhichidentifiedherbicideresistanceinanumberofgrass weeds in the Selwyn District last summer, will be run in South Canterbury in the coming months.

South Canterbury no-till advocate Mike Porter had a quick hello-goodbye trip to Argentina in August to attend the Aapresid Annual Congress and the National Agtech Congress.

The trip was supported by FAR and the Argentine government in recognition of FAR’s ongoing collaboration with Aapresid, the Argentine No-till Association. Mike says he accepted the offer as he was very keen to find out more about the Argentine experience of no-till.

“I really wanted to see what they did and how they did it. Around 10 percent of New Zealand arable farmers are no-till, while in Argentina, that number is closer to 94 percent. What’s driving that and why does it work so well for them?”

It seems the answer lies in some pretty degraded soils. “At home when I put pressure on a handful of soil I often get a mud pie, whereas in Argentina, the soil is so fragile, that the same pressure would often produce a handful of dust. Lucky for them their soil is deep, and with on-going no-till there is the potential for it to improve.”

Cover crops are being used a lot to protect the soil quality.

“They’ll sneak a cover crop in whenever they can. We saw ryegrass cover crops in corn that had been sown with a fertiliser boom spreader. This approach gave them very high, up to two metres of clearance, so the ryegrass could be broadcast just before harvest.”

Several new technologies caught his eye at the Agtech Congress. These included a silo bag sensor that recorded and messaged out measurements such as grain moisture, humidity and CO2 levels from within silage bags, a web-based grain market, which he describes as TradeMe for grain, and artificial intelligence software that can test grain quality using high resolution imagery.

“A lot of the technology I saw was about supporting decision making, making it easier to make decision about everything from crop nutrition to grain sales.”

During his 10-day trip Mike met with Luis Urriza, Argentina’s Under Secretary for Agriculture, visited a soybean crushing plant that can process 320,000 tonnes of soya each day, and spent time at the Rosario Stock Market, which only trades grain. He also spent time with Eddie Nolan, from Aapresid, who spoke at FAR’s 2017 Conference.

Hola y adiós Argentina

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Coming to terms with glyphosate risk

Ian Shaw, Professor of Toxicology, University of Canterbury.

Pesticide risk assessmentWhen a new pesticide is approved for marketing it goes through a risk assessment process which involves extensive toxicology (environmental and ‘human’) and efficacy studies. The toxic effects (risk) of the compound are weighed against its efficacy (benefit); in short, if benefit wins the compound will likely be approved for marketing, if risk wins it will not. The approval to market stays in place until the government reviews the compound in light of new information, or decides to revoke the approval for other reasons. The review of pesticides is a constant process as new information is constantly being produced by scientists. In New Zealand, the Environmental Protection Authority (NZEPA) usually decides what to review and lays down the review process.

Figure 1. The shikimate pathway leading to the biosynthesis of aromatic amino acids which are essential for plants. Glyphosate (inset top right in red) inhibits the enzyme EPSP synthase because of its structural similarity to its natural substrate, phosphoenolpyruvate.

Environmental impact of glyphosate Unfortunately, the overzealous use of glyphosate is leading to weed resistance and so reducing its efficacy. In addition, toxicological issues are beginning to show up which were not tested for during its development in the 1970s. It is well known that glyphosate is efficiently broken down by soil bacteria; however, it is becoming clear that while soil bacteria degrade a good proportion of glyphosate, some is adsorbed by soil particles and thus persists for longer than originally thought.

The most perplexing of the recently identified properties of glyphosate is its behaviour as an estrogen mimic. There is increasing concern about chemicals that mimic the female hormone estradiol because of the effects they can have on humans and creatures in the environment. The World Health Organisation (WHO) reviewed endocrine disrupting chemicals in 2013 and concluded that they are likely to be responsible for numerous ‘strange’ effects emerging in humans and other animals (e.g., reduced sperm count in humans, effects on fish breeding).

My research group is trying to work out how glyphosate mimics estradiol; using a computer molecular modelling approach, we have very recently shown that it can bind to estrogen receptors, even though its molecule does not appear to have the right attributes to bind (Figure 2). In short; glyphosate is estrogenic.

There are many estrogenic chemicals in the environment and their effects are additive. So, glyphosate is adding to the environment’s feminising load. Since so much glyphosate is used, this could have significant environmental impact.

Figure 2. Schematic representation of estradiol (black) bound to the ligand binding cleft of the estrogen receptor, showing the molecular requirements for binding and activation of the receptor (adapted from Shaw (2018), Food Safety – The Science of Keeping Food Safe, Wiley-Blackwell). Glyphosate (red) appears to have none of the molecular requirements to bind to and activate estrogen receptors.

The birth of RoundupIn the 1970s, there was great interest in developing pesticides to increase the efficiency of farming. The ideal pesticides would be effective, target specific, have a short environmental residence time and not lead to food residues.

During this period, John Franz working for Monsanto in Missouri, USA, came across N-(phosphonomethyl)glycine, which soon became known as glyphosate. Glyphosate inhibits a key enzyme that makes aromatic amino acids (the shikimate pathway; Figure 1). Plants cannot survive without aromatic amino acids and so glyphosate kills them…dead!

HNP

OO

OO

O

HOOH

Phenolic hydroxyl group binding site

Aliphatic hydroxyl group binding site

Hydrophobic binding region

O O

OP

O

OO

OH

OH

+O

OO

O

O O

OP

O

OO

OH

OO

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PO32-

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AROMATIC AMINO ACIDS

EPSP Synthase

Shikimate-3-phosphate Phosphoenolpyruvate

5-Enol-pyruvateshikimate-3-phosphate

HN

P

O

O

O

O

O

Glyphosate

RISK = HAZARD x EXPOSURERisk is determined by the level and duration of exposure to a hazard. Hazard is the intrinsic toxicological properties of the test chemical - it is usually measured by the no observable adverse effect level (NOAEL) which is the highest dose at which there is no effect in animal tests.

Since the shikimate pathway is plant specific it was thought unlikely (if not impossible) that glyphosate would impact animal (including human) biochemistry. Additionally, glyphosate was found to be quickly degraded to harmless breakdown products by soil bacteria.

Glyphosate was approved for use in the USA as the active principle of Roundup in 1974, and is now the most used herbicide worldwide. It has revolutionised farming practice, particularly since the development of Roundup Ready crops which are genetically modified to be resistant to the effects of glyphosate, allowing Roundup to be used to kill weeds growing among the crops without harming the crop itself.

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The environmental (and human) impact of glyphosate is now far greater than could have been appreciated when it was first assessed in the 1970s because of the enormous change in its use and usefulness. Originally glyphosate was used as a simple herbicide, now it is used as an integral part of agricultural practice. For example, in New Zealand, glyphosate is extensively used to terminate pastures before crop establishment or pasture renewal, mitigating the need to till and thus reducing soil erosion. But, as a result of this evolution of use, the risk of residues in milk increases if dairy cattle graze glyphosate-treated pasture (Figure 3). In the USA, the potential residue issues are far greater since the introduction of Roundup Ready crops which are treated directly with glyphosate.

Where next for glyphosate use in New Zealand?The NZEPA recently published its Priority Chemicals List – this is the 40 priority chemicals for review. Glyphosate, surprisingly, is not on the list; but is considered high priority for review by other countries and jurisdictions. One of the reasons the NZEPA gave for not listing glyphosate is the 2016 review mentioned earlier. However, this review did not consider glyphosate’s environmental toxicity, which is clearly a very important for an environmental estrogen mimic.

This article might read like a case to ban glyphosate. It is not. But it is a plea to reconsider the way we use it (an NZEPA review would help this process considerably). Its overzealous use is leading to potentially very undesirable outcomes, including resistance, environmental impacts and human health effects. These are unacceptable and will lead to the demise of this most important of herbicides.

Risk is directly related to exposure, and so to reduce risk we must reduce exposure. And to reduce exposure we must reduce use. I believe it is time to round up Roundup and use it only when absolutely necessary, not just when it is convenient. This includes agricultural and amenities use – is it really necessary for Councils to use glyphosate to kill roadside herbage in Canterbury?

This article is based on a plenary lecture given at the FAR’s Research Leading Change Conference on 28 June, 2019.

Figure 3. A pasture killed with glyphosate (left), and the same pasture a week later grazed by cattle (right). Clearly, glyphosate remaining in the herbage is being consumed by the cattle. The animals in this photograph are not dairy cattle.

Glyphosate is a probably a human carcinogen except in New ZealandAnother blow to glyphosate’s apparently clean slate was the International Agency for Research on Cancer’s (IARC – a sub-group of the WHO) classification of it as Carcinogen 2A (probably carcinogenic to humans) in 2014. This was based on animal cancer studies and glyphosate being associated with specific cancers (e.g. non-Hodgkin lymphoma) in exposed farmworkers. A 2016 New Zealand government commissioned review of the IARC classification concluded that glyphosate is unlikely to be a human carcinogen and is unlikely to be genotoxic. I disagree with the first statement, but agree with the latter. The review did not consider non-genotoxic mechanisms of carcinogenesis, and, in my opinion, glyphosate is more likely to act by a non-gene-based mechanism (i.e. via its estrogen receptor effects).

In my view, glyphosate has significant work place health and safety implications. Indeed, this year a USA court awarded a man US$80 million (NZ$121 million) compensation for what they judged was cancer caused by his exposure to glyphosate.

Changing use of glyphosate signals changes in environmental and human impactsThe argument that residues in food are unlikely to present an unacceptable risk to consumers was based on anticipated use of glyphosate in the 1970s. Moreover, it was not based on ‘actual’ residue measurements, but rather on maximum residue limits (MRLs). This approach is not a bad idea because it works on the premise that since it is illegal to market food that has residues which exceed MRLs, the worst case residue in a particular food will be the MRL. For example, wheat consumption (from dietary surveys) is 0.178 kg/person/day and the MRL for glyphosate in wheat is 10 mg/kg; therefore, the worst case glyphosate intake from wheat is 1.78 mg/person/day. This can be done for all of the foods with MRLs set and added together to give a total daily glyphosate intake. This was all well and good at the time, but as glyphosate use patterns have changed residues levels are likely to have changed too. This is exemplified by glyphosate residues found in ice cream in the USA in 2017.

AUSTRALIAAUSTRALIA

Expanding across the high yielding zones

Stubble retention guideA stubble retention guide has been developed out of the 2013-2018 GRDC funded research collaboration between FAR Australia and the Riverine Plains Farming Group. The GRDC Stubble project looked at the management of stubble and its influence on crop establishment and subsequent agronomy and was led by FAR Australia Research Manager Michael Straight and Riverine Plains Research Co-Ordinator Dr Cassandra Schefe. Stubble Retention in cropping systems of the Riverine Plains summarises the results of the project and will available by the end of this year.

FAR Australia is continuing to move towards its goal of establishing a national network of research platforms in the country’s high yielding productivity zones. Research hubs are running, or being set up in Bannockburn, southern Victoria; Mulwala, southern NSW; and Esperance, Western Australia.

These hubs are intended to cover the principal high rainfall zones (HRZ) of southern Australia along with the main irrigated region of the country. Their development has been underpinned by the initiation of two GRDC funded projects.

The project in Western Australia, Optimising high rainfall zone cropping for profit in the Western and Southern Regions, involves a collaboration with the state department of Agriculture (DPIRD) and the Commonwealth Scientific Industrial Research Organisation (CSIRO). This work was mentioned in our last newsletter. Research on the second project, Development and validation of soil amelioration and agronomic practices to realise the genetic potential of grain crops grown under a high yield potential, irrigated environment, is being carried out in the irrigated regions of the eastern states, primarily southern New South Wales and northern Victoria.

This GRDC irrigation investment will develop and validate crop specific agronomic practices to maximise system profitability. Around 65 trials will be managed by FAR Australia and the Irrigated Cropping Council at a series of Irrigated Research Centres each year. They will focus on: • Optimising return on nitrogen through improved efficiency. • Improving the understanding of N form, timing and rate in the

context of irrigation timing and inter-related agronomic decisions. • Understanding how to consistently optimise yield (in the context of

water price, input costs and commodity price) for the crops where yield gaps are most apparent (canola, faba beans, chickpeas, durum, grain maize and barley).

With a devastating drought in the eastern states and water priced at over $600 a megalitre, it has not been an easy task trying to get the project initiated!

For further information please contact nick.poole@faraustralia.com.au

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2019Arable Research In Action

ARIAFAR Arable Research Site, State Highway 1, Chertsey

Wednesday 4 December 2019, 10.45am – 4.00pm

Planning is well underway for FAR’s Arable Research in Action (ARIA) field day at Chertsey on Wednesday 4 December.

The event, which is held every second year, puts the spotlight on FAR’s crop research, with an emphasis on field trials. There will be 10 presentations from FAR and invited guests, including Carol Mallory-Smith, from Oregon State University.

Each presentation will be held twice, in the morning and again after lunch.

Other speakers will provide updates on the latest grain and seed agronomy research, while industry-wide issues such as the environment, soil quality and disease management will also be covered.

ARIA starts at around 10.45am with a welcome and finishes up at 4.00pm with refreshments and a barbecue.

We look forward to seeing you there.

For more information visit www.far.org.nz or phone 03 345 5783.

Topics and Speakers

1. Influence of cultivar on cereal diseases Jo Drummond, FAR

2. Ramularia update Soonie Chng, Plant & Food Research

3. Cover crops for weed management Matilda Gunnarsson and Phil Rolston, FAR

4. Herbicide resistance – a US perspective Carol Mallory-Smith, Oregon State University

5. Stem rust – can we predict it? Richard Chynoweth, FAR

6. Options for improving glyphosate efficacy Phil Rolston, FAR

7. Soil quality – a visual analysis Abie Horrocks, FAR

8. The how and why of Quick N testing Diana Mathers, FAR

9. Red clover case bearer update Scott Hardwick, AgResearch

10. Drone flies and pollination Brad Howlett, Plant & Food Research

FAR Northern Crop Research Site, Oaklea Lane, TamahereThursday 12 December, 2019, 11.00am – 4.00pm

NCRS field day 2019

The programme for FAR’s annual Northern Crop Research Site (NCRS) field day will focus on two issues that are high on the list of farmer concerns at present: weed management and farming within the rules.

FAR’s Allister Holmes says the morning will focus on weed management, with particular emphasis on sustainable weed management.

“We’re lucky to have Emeritus Professor Carol Mallory-Smith from Oregon State University and Charles ‘Merf’ Merfield, formerly from the Lincoln University Biological Husbandry Unit on the programme. Carol is an expert on herbicide resistance and will discuss

issues around how to prevent the onset of what can be a very costly crop management issue. Merf will explain the benefits of an integrated weed management system; his talk will include a demonstration of a camera controlled inter-row cultivator. These talks fit

neatly with the following topic of biosecurity, which will focus on protecting your farm border.”

The afternoon will be given over to discussing how to farm within increasingly complex regulatory environment. FAR’s Diana Mathers will summarise recent freshwater and climate change discussions and provide information on how to

get started with environmental compliance recording and reporting.

For more information contact anna.heslop@far.org.nz.

Topics and Speakers

Weed management

11.00 Welcome

11.15 Understanding herbicide resistance Carol Mallory-Smith, Oregon State University

11.45 Integrated management of weeds Charles Merfield

12.45 Biosecurity Abie Horrocks, FAR

1.00 Velvetleaf Trevor James, AgResearch and Heidi Pene, Waikato Regional Council

1.15 LUNCH

Farming within the rules

2.00 Environmental compliance: how to get some points on the board

Diana Mathers and Allister Holmes, FAR; John Austin and Colin Jackson, growers.

3.15 Mini visual soil assessment Abie Horrocks and Sam McDougall, FAR

3.45 Closing

4.00 Refreshments

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Good management practices for setback strips on cropping farmsSediment from farm run-off is an economic loss to the farm and an environmental risk to water quality. To minimise this risk, setback zones can be created between crop margins and waterways to filter sediment out of run-off before it leaves the paddock. But very little is known about what is the most effective width for such setbacks on differing soil types and slopes.

This is where the Good Management Practices for Setback Strips on Cropping Farms project comes in. Led by FAR’s Abie Horrocks, and supported by the Sustainable Farming Fund, the project is looking at clarifying the width at which sediment is kept out of waterways, but productive area is least compromised.

As part of the project, setback monitoring sites have been established on three very different farms in Leeston (Central Canterbury), Makikihi (South Canterbury) and Otane (Hawkes Bay). On each of the properties a purpose built, automated setup captures run-off on a control plot with no setback, a plot with a 1 m setback and another plot with a 5 m setback strip (planted in Timothy). At this stage the timothy has not grown enough to be effective in filtering run-off. However, the data we do have can be compared to run-off events once the setback has been established to see any filtering effect.

What has been surprising is how little rain is required to cause a run-off event, even on near flat ground. The Leeston site has

a 2 degree slope and after 14 mm of rain with the soil 29% saturated before the rain there was 1.2 mm of run off (Figure 1). Even though this is a small amount, it will still be carrying sediment off the paddock.

The trial is set to run for another two years, and at the end of this time we hope to have sufficient data to create a good management practice guide for setback strips on cropping farms.

Will Mitchell

Figure 1. Run-off, rainfall and soil water content (SWC) from 1 m setback strip in Leeston, 7 -16 August 2019.

Soil w

ater

con

tent

(L/L

)

Rain

fall (

mm

/h) &

tota

l run

off (m

m)

Rainfall SWC Runoff

0.40

0.35

0.30

0.25

0.20

0.15

0.10

0.05

0

2.5

2.0

1.5

1.0

0.5

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