Australian Government's Rural Research and Development for Profit trials

In southern Australian mixed farming systems, there are many opportunities for pasture improvement. The Dryland Legume Pasture Systems (DLPS) project aims to boost profit and reduce risk in medium and low rainfall areas by developing pasture legumes that benefit animal and crop production systems. A component of the DLPS project aims to quantify the impacts of different pasture
legume species on livestock production and health. Included are widely grown legumes (strand medics and vetch) and legumes
with reasonable prospects of commercialisation (trigonella).
A five-year grazing system trial was established at the Minnipa Agricultural Centre (MAC) in 2018. It is the main livestock field site
for the DLPS program in southern Australia.

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, and improve soil fertility through nitrogen (N) fixation. Despite these benefits, pasture renovation rates remain low and there are opportunities to improve the pasture base on many low to medium rainfall mixed farms across southern Australia. There are also reports of poor protein levels in wheat following medic pastures and many reports of poor medic nodulation. Previous work has shown that substantial responses to inoculation are possible in the Victorian Mallee, which is possibly linked to the poor N fixation capacity of some populations of soil rhizobia. The extent to which inoculation can still improve medic nodulation on Eyre Peninsula requires clarification.

The Dryland Legume Pasture Systems (DLPS) project aims to develop recently discovered pasture legumes together with innovative management techniques that benefit animal and crop production and promote their adoption on mixed farms in the low and medium rainfall areas of WA, SA, Vic and southern NSW.  One objective within this work program is to increase the amount of fixed N provided by the pasture.

This is a component of a new five year Rural Research and Development for Profit funded project supported by GRDC, MLA and AWI; and involving Murdoch University, CSIRO, SARDI, Department of Primary Industries and Regional Development; Charles Sturt University and grower groups.

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, and improve fertility through nitrogen (N) fixation. 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 needed 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.

The Dryland Legume Pasture Systems project will both develop and evaluate a range of pasture legumes together with innovative establishment techniques, measure their downstream benefits to animal and crop production and promote their adoption on mixed farms.

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, and improve fertility through nitrogen (N) fixation. 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 needed 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.

The Dryland Legume Pasture Systems project will both develop and evaluate a range of pasture legumes together with innovative establishment techniques, measure their downstream benefits to animal and crop production and promote their adoption on mixed farms.

This trial was established in 2018 to assess a diverse range of annual pasture legumes in order to determine whether there are more productive and persistent options for the drier areas (< 400 mm) of the mixed farming zone of southern Australia. In 2019 the trial was allowed to regenerate to determine which legumes regenerated and how their performance differed from the establishment year.

The Dryland Legume Pasture Systems project will both develop and evaluate a range of pasture legumes together with innovative establishment techniques, measure their downstream benefits to animal and crop production and promote their adoption on mixed farms.

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.

Over the past three decades there has been a shift from integrated crop-livestock production to intensive cropping in dry areas, which has significantly reduced the resilience of farms in low to medium rainfall areas. Intensive cropping is prone to herbicide resistant weeds, large nitrogen fertiliser requirements, and major financial shocks due to frost, drought or low grain prices. 
A pilot project with MLA and AWi in WA and southern NSW has demonstrated how novel pasture legumes such as serradella, biserrula and bladder clover can improve livestock production while reducing nitrogen requirements, weeds and diseases for following crops. The extent to which these new legumes establish, grow and persist on South Australia's alkaline sandy soils requires clarification. 
The demonstration sites are primarily an extension tool, unlike research trials requiring detailed data collection. The purpose of these sites is to gather information on regional legume performance, including benefits to the crops that follow. 

In southern Australian mixed farming systems, there are many opportunities for pasture improvement, providing positive impacts to both cropping and livestock systems. Dryland legume pastures are necessary in low to medium rainfall zones to support productive and healthy livestock, along with optimal production in crops following these pastures. The majority of pasture species used in these mixed farming systems are short-lived annuals that complete their lifecycle from winter to early summer, with dry seasonal conditions resulting in a shorter growth window between germination and senescence. This is a major issue for livestock producers in these regions due to unreliable rainfall patterns leading to fluctuating legume growth, and the subsequent impact on feed supply and quality for grazing animals.

Innovative and improved legume species and pasture systems have the potential to fill existing nutrient gaps, thus reducing supplementary feed required for optimum ruminant performance, and maintain or improve livestock productivity through growth rates, fertility or product quality.

The Dryland Legume Pasture Systems (DLPS) project aims to boost profit and reduce risk in medium and low rainfall areas by developing recently discovered pasture legumes together with innovative management techniques that benefit animal and crop production and farm logistics. A theme of the DLPS project involves ‘Quantifying the benefits of novel legume pastures to livestock production systems’ and aims to maximise the advantages that pastures provide to livestock through increased animal growth and reproduction by extending the period of quality feed and reduced supplementary feeding. The animal systems research within the project will also assess areas of understanding anti-nutritional factors and ‘duty of care’ for new pasture species, providing opportunities for improved weed management and evaluate the main benefits of novel self-regenerating pasture legumes in crop rotations on animal production, health and welfare.

This theme is a component of a five year Rural R&D for Profit funded project supported by GRDC, MLA and AWI; and involving Murdoch University, CSIRO, SARDI, Department of Primary Industries and Regional Development; Charles Sturt University and grower groups.

A five-year grazing system trial was established at the Minnipa Agricultural Centre (MAC) in 2018 to examine this theme and is the main livestock field site for the DLPS trial in the southern region of Australia.

The project has two components: an agronomy component that will assess the impact of varying surface irrigation management strategies (scheduling and frequency) on nitrogen use efficiency, water use efficiency and overall system profitability; and a hydrology component that will develop irrigation design criteria that will allow precise application of water in basin irrigation layouts, such as bankless channel systems, allowing flexible management to match recommendations from the project’s agronomy component.
 

This research aimed to identify the impact of irrigation opportunity time and fertiliser N rates on fertiliser N response, lint yield and fertiliser N recovery in a sub-surface drip irrigation system.