Medic trials

Why do the trial? 
Barley grass possesses several biological traits that make it difficult for growers to manage it in the low rainfall zone, so it is not surprising that it is becoming more prevalent in field crops in SA and WA. A survey by Llewellyn et al. (2015) showed that barley grass has now made its way into the top 1 O weeds of Australian cropping in terms of area infested, crop yield loss and revenue loss. 
The biological traits that make barley grass difficult for growers to manage in low rainfall zones include: 

- early onset of seed production, which reduces effectiveness of crop-topping or spray-topping in pastures,
shedding seeds well before crop harvest, reducing harvest weed seed control effectiveness compared to weeds such as ryegrass which has a much higher seed retention,•    increased seed dormancy, reducing weed control from knockdown herbicides due to delayed emergence, and
•    increasing herbicide resistance, especially to Group A herbicides, used to control grass weeds in pasture phase and legume crops. 

Barley grass management is likely to be more challenging in the low rainfall zone because the growing seasons tend to be more variable in terms of rainfall, which can affect the performance of the pre-emergence herbicides. Furthermore, many growers in these areas tend to have lower budgets for management tactics, and break crops are generally perceived as more risky than cereals. Therefore, wheat and barley tend to be the dominant crops in the low rainfall zone. This project is undertaking coordinated research with farming systems groups across the Southern and Western cropping regions to demonstrate tactics that can be reliably used to improve the management of barley grass. 

Part 1: Medic cultivars were grown in soil with high boron levels in a glasshouse, leaf damage symptoms recorded and cultivars allocated to different tolerance groups (Howie 2012). 

Part 2: The above identified that all spineless burr medic cultivars are susceptible to high boron levels. Screening wild accessions (supplied by the Australian Pasture Genebank) identified a burr medic accession with boron tolerance and vigorous growth. The boron tolerant accession was crossed with current spineless burr medic cultivars Scimitar and Cavalier. F2 plants with high early vigour were selected and a molecular marker used to identify homozygous boron tolerant plants. A single seed descent breeding method using speed breeding was used to obtain uniform lines. Lines were seed increased at Waite in 2018 and lines with the highest agronomic performance selected for 2019 field evaluation trials. A cohort of 16 boron tolerant lines along with their  parents and barrel medic cultivars that differ in boron tolerance, were sown at Roseworthy and Minnipa. The trials were managed as best practice first year annual medics to maximise dry matter and seed production. Best practice consists of a high sowing rate (10 kg/ha), controlling broadleaf and grass weeds, monitoring and controlling insects and no grazing. Dry matter production was  assessed and pods collected. Seed yield will be determined by April 2020.

There are reports of low grain protein levels in wheat following medic pastures and many observations of poor medic nodulation. Previous work has shown that rhizobial inoculation can improve the nodulation of medics in the SA and Victorian Mallee, and that more generally about 50% of the populations of medic rhizobia in soils are suboptimal in their nitrogen (N) fixation
capacity. This trial aimed to:
• Determine if inoculation can improve medic nodulation at Minnipa,
• Quantify the amount of N fixed by different legumes, and
• Assess impacts on the following wheat crop.

Legume pastures have been pivotal to sustainable agricultural development in southern Australia. They provide highly nutritious feed for livestock, act as a disease break for many cereal root pathogens, improve fertility through nitrogen (N) fixation and mixed farming reduces economic risk. Despite these benefits, pasture renovation rates remain low and there is opportunity to improve the quality of the pasture base on many low to medium rainfall mixed farms across southern Australia. A diverse range of pasture legume cultivars are currently available to growers and new material is being developed. Some of these legumes, such as the annual medics, are well adapted to alkaline soils and have high levels of hard seed, which allow them to self-regenerate from
soil seed reserves after cropping (ley farming system). Other legume cultivars and species are available and being developed that
offer improved seed harvestability, are claimed to be better suited to establishment when dry sown and/or provide better nutrition for
livestock. Regional evaluation is being undertaken to determine if they are productive and able to persist in drier areas (<400 mm
annual rainfall) and on Mallee soil types common to the mixed farming zone of southern Australia.

Barley grass continues to be a major grass weed in cereal cropping regions on upper Eyre Peninsula (EP). The use of unmanned aerial vehicle (UAV) technology to identify and assess barley grass populations in paddocks and monitor potential resistant populations may be a useful tool for farmers. This approach was tested in three paddocks on upper EP Minnipa Agricultural Centre (MAC), Minnipa Hill and Yaninee using a UAV during the 2017, 2018 and 2019 growing seasons at three different timings, with paddock transects conducted to verify grass weed density in paddocks. In 2019 grass weed escape paddocks were targeted at MAC and Condada in the final flights.

The aim of the research was to determine if the UAV imagery could monitor the grass weed populations across seasons in crops and pastures, if resistant weed patches were continually in the same area of the paddock and if the information could be useful for farmers to adopt this method to better target grass weed control.

The expected outcome of the project is that by 2021, growers in the MRZ of the South East and their advisors will have access to new relevant information on diverse crop rotations and integrated farming systems, particularity the incorporation of a pasture phase. 

To identify plant varieties or mixtures that can increase dry matter production of the pasture break phase on the highly alkaline soils of upper Eyre Peninsula. Current cropping and grazing systems are mostly based on monocultures and the potential feed base of the break phase could be broadened to be more productive for grazing and available for a longer time period in the season. Current oat varieties, mixed break crops and newer pasture species were trialled at Piednippie in 2018 to investigate whether a more productive and prolonged feed base is possible.

The GRDC project ‘Maintaining profitable farming systems with retained stubble - upper Eyre Peninsula’ aims to produce sustainable management guidelines to control pests, weeds and diseases while retaining stubble to maintain or improve soil health, and reduce exposure to wind erosion. The major outcome to be achieved is increased knowledge and skills allowing farmers and advisers to improve farm profitability while retaining stubble in farming systems on upper Eyre Peninsula (EP).

One issue Mount Cooper farmers identified as an issue was the establishment of self-regenerating medic pastures into heavy stubble residues. The trial reported here was designed to compare medic establishment and production, with different management strategies imposed on the previous crop stubble residues.

The GRDC project ‘Maintaining profitable farming systems with retained stubble - upper Eyre Peninsula’ aims to produce sustainable management guidelines to control pests, weeds and diseases while retaining stubble to maintain or improve soil health, and reduce exposure to wind erosion. The major outcome to be achieved is increased knowledge and skills allowing farmers and advisers to improve farm profitability while retaining stubble in farming systems on upper Eyre Peninsula (EP).

The Minnipa Agricultural Centre S3S pasture trial was established in 2013 to assess the impact of a two year medic pasture break on barley grass. The trial had different grass weed management and tillage treatments imposed in 2013 and 2014. The trials were sown with wheat in 2015 and 2016, and allowed to regenerate with medic pasture in 2017.

The broad aim of this 3 year SAGIT funded project was to investigate if current management tools for medic based pastures, such as herbicides, fertilisers and rhizobial inoculants, are affecting N fixation by medic pastures under field conditions typical of the upper Eyre Peninsula.

The expected outcome of the project is that by 2021, growers in the MRZ of the South East and their advisors will have access to new relevant information on diverse crop rotations and integrated farming systems, particularity the incorporation of a pasture phase. This will allow for better crop sequencing decision making, with the aim of increasing farm sustainability, diversity and ultimately profitability, through the adoption of improved rotations and break crop management options.

To assess the impact of soil nutrition, current herbicides, adjuvants and rhizobial inoculants on N fixation by medics under field conditions typical of the upper Eyre Peninsula. 

To investigate the impact of grazing, soil nutrition and rhizobial inoculants on dry matter production, nodulation and N₂-fixation of a regenerating medic pasture under field conditions.

• To investigate legume pasture options for controlling group A (ACCase inhibitors) resistant barley grass (GRDC project UA00149).
• The trial also looked at the impact of these pasture treatments on a subsequent wheat crop and compared one vs. two consecutive years of legume pasture on barley grass management in the absence of group A herbicides.

Interviews were conducted on each farm to determine for each paddock the species that were sown

To evaluate Ecopar for controlling flowering and podding wild raddish in pasture.

The GRDC project ‘Maintaining profitable farming systems with retained stubble - upper Eyre Peninsula’ aims to produce sustainable management guidelines to control pests, weeds and diseases while retaining stubble to maintain or improve soil health, and reduce exposure to wind erosion. The major outcome to be achieved is increased knowledge and skills allowing farmers and advisers to improve farm profitability while retaining stubble in farming systems on upper Eyre Peninsula (EP).

One issue upper EP farmers identified as a problem was sowing into retained pasture residue with pasture vines causing issues with blockages at sowing and uneven germination. Also establishing legume pastures into heavy stubble residues has also an issue in this region. The trial at Mount Cooper was designed to compare plant establishment and production, and weed and pest control effectiveness in the presence and absence of previous crop or legume pasture residues.

A long-term study was established at the Minnipa Agricultural Centre from 2008 to 2015 (EPFS Summaries 2008 to 2014) to assess the impact of grazing on crop and pasture production and soil health and also to evaluate this from a systems perspective.

The eight year demonstration with a wheat, wheat, pasture (volunteer and sown annual medic), wheat, pasture (self-regenerating annual medic), wheat and wheat rotation was also established to determine whether productivity could be improved under a higher input system compared to a lower input and more traditional system and what affect this had on soil fertility.

To assess the impact of soil nutrition, current herbicides, adjuvants and rhizobial inoculants on nitrogen (N) fixation by medics under field conditions typical of the upper Eyre Peninsula. 

To look at current techniques used by farmers, or recommended by consultants, to improve medic pastures and determine the most effective method to optimise N₂-fixation. Biomass, nodulation and N₂-fixation differences between management practices, including inoculation treatments on both sown and regenerating medic stands were measured. The trial also investigated if grazing medic pastures in the break phase of the rotation benefits or impedes nodulation and subsequent N₂-fixation.

Onion weed (Asphodelus fistulosusis) is a significant pest of crops and pastures on many soil types on upper EP. Onion weed that germinates in the pasture phase often results in thick stands of large plants that require repeated herbicide application and/or cultivation to control prior to a crop phase. Cultivation prior to sowing is a widespread practice to control the weed and reduce the residues to manageable levels. However, cultivation can expose the soil to erosion.

Onion weed in pastures regularly sets seed prior to the end of the growing season, ensuring the seed bank is replenished and the weed persists in every phase of the rotation. A key strategy to reduce the impact of onion weed, and the need for cultivation, is to reduce growth and seed set in the pasture phase of the rotation. Non-selective herbicides can control actively growing onion weed plants, but pasture growth is also affected.

Previous trials by the UNFS group, MDB NRM, and PIRSA have shown the following herbicides can provide adequate control of onion weed in non-selective situations:

                    Paraquat and double knocks of paraquat

                    Glyphosate plus metsulfuron methyl mixtures (+/- paraquat second knock)

                    Glyphosate plus LVE ester 2,4- D plus metsulfuron methyl,( +/- paraquat second knock)

                    Chlorsulfuron

                    Spray Seed

                    Alliance

This trial was established to investigate herbicide control of autumn/winter germinating onion weed in the pasture phase, while maintaining the productivity of the medic pasture. This trial evaluated the herbicide control of young actively growing onion weed in a vigorous medic pasture. The herbicides, with the exception of paraquat, were chosen to minimise the impact on the medic biomass production.

Sheep are an integral part of low-medium rainfall mixed farming systems across southern Australia and they account for 23% of Australia’s total livestock emissions. Apart from the contribution to anthropogenic greenhouse gas emissions, the energy lost as methane represents a significant inefficiency in sheep production systems. Therefore, maintaining or improving the balance between forage and animal productivity, and methane emissions is likely to be a challenge under a warmer and drier climate. The aim of this trial is to evaluate pasture/forage options to fill in the late-spring, autumn and early winter feed gaps; and to measure comparative animal production, feed quality and methane emissions in response to current and improved sheep feeding strategies.

To demonstrate establishment, management and viability of legume phase options in cropping rotations with appropriate agronomic management packages.

This research identified the plant traits most likely to determine differences in external critical phosphorus (P) requirements (i.e. the soil extractable-P concentration required to achieve 90% of maximum yield) of pasture legume species. Understanding trait differences that affect critical P requirements of pasture legumes is important in providing confidence around field differences in external critical P requirement.

To quantify the agronomic benefits that break crops can provide in Mallee cropping rotations so that farmers can be confident of the long term benefits of more diverse crop sequences.

The aim of this project was to test if including one or two-year break phases in low rainfall crop sequences could successfully address agronomic constraints to increase the productivity of subsequent cereal crops and improve the profitability of the long term crop sequence when compared to maintaining continuous cereal

To investigate the dry matter (DM) productivity and nutritive value (NV) of a range of pasture species sown independently or in conjunction with Fathom barley at Hart in winter and summer.

To evaluate emerging and newly released medic, vetch and forage peas varieties for their ability to produce dry matter and nutritive value for stock in the Mallee and Wimmera environments.

To look at the impact of 2012 break crops on Rhizoctonia inoculum in 2013 and of crop management on disease expression in the 2013 cereal crop. 

To assess and evaluated a range of different pasture varieties at three different sites.

To assess and evaluated a range of different pasture varieties at three different sites.

The GRDC Low Rainfall Crop Sequencing project is identifying the effects that different break crops and rotations have on Mallee farming systems. Farmers have increasingly adopted continuous cereal cropping strategies as non-cereal crops are perceived as riskier than cereals due to greater yield and price fluctuations. Therefore, it is important to quantify the agronomic benefits that break crops can provide in Mallee cropping rotations so that farmers can be confident of the long term benefits of more diverse crop sequences.

To measure and quantify N2O emissions from wheat grown in rotation with canola, pulses and legume pastures at two sites in low and medium/high rainfall farming systems of the Eyre Peninsula, while assessing best management practices that local farmers can adopt to reduce the risk of N2O losses and ultimately improve the paddock’s crop productivity and gross margin.

Agricultural soils are the main source of emission of the greenhouse gas (GHG) nitrous oxide (N2O) to the atmosphere. N2O is a potent GHG which lasts in the atmosphere for 114 years and has a global warming potential of approximately 300 times greater than that of carbon dioxide over a 100 year timescale. Agriculture accounts for 16% of Australia’s greenhouse gas emissions but produces 80% of Australia’s N2O emissions. This project seeks to measure and quantify N2O emissions from wheat grown in rotation with canola, pulses and legume pastures at two sites in low and medium/high rainfall farming systems of the Eyre Peninsula, while assessing best management practices that local farmers can adopt to reduce the risk of N2O losses and ultimately improve the paddock’s crop productivity and gross margin.

Investigate the dry matter accumulation and timing of a range of pastrure species and mixes and comparing them to the dry matter production by crops that are grown to be grazed before being shut up for grain production or cut for hay or silage.

Investigate the dry matter accumulation and timing of a range of pastrure species and mixes and comparing them to the dry matter production by crops that are grown to be grazed before being shut up for grain production or cut for hay or silage.

To determine if disease suppression against rhizoctonia is achievable in an upper EP environment on a grey highly calcareous soil. It also assessed whether soil microbial populations can be influenced by rotation and fertiliser inputs in this environment.

To investigate whether the VRT approach will markedly shift yields and profitability from the levels achieved using blanket inputs across the whole paddock in the Minnipa region.

To recommend options to improve;
• soil nutrients and groundcover, and 
• reduce disease levels and chemical use.

To assess the potential of a range of multi-trait breeders’ lines for commercial development.

• The Minnipa Agricultural Centre (MAC) has been funded by Grains Research and Development Corporation (GRDC) to run a research and extension program (Eyre Peninsula Farming Systems 3 – Responsive Farming Systems) to improve water use efficiency on farms by 10% on upper Eyre Peninsula (EP). This is seen as one of the main ways to improve profit and manage risk for farm businesses.

To determine if disease suppression against Rhizoctonia is achievable in an upper EP environment on a grey
highly calcareous soil using different rotations and cropping inputs.

To assess the long-term impact of a range of P fertiliser rates on crop yield and economic returns

To investiage management of risk through tailoring inputs to the different production zones
potential by using variable rate technology.

Investigation into the best economic solutions to pasture establishment, persistence and management to ensure long term productive grazing systems.

To test whether soil fertility and health could be improved under a higher input system compared with a lower input and more traditional system.

The purpose of the trial was to compare growth rates and dry matter production of alternative pastures with traditional medic pastures

To compare the production of different winter pastures and their recovery from grazing.

To assess the performance of annual medics in a pasture – wheat rotation over the 2009 and 2010 seasons.

To collect more data on dry matter and production figures for forage varieties.