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HALO project shines light on Broomehill nitrogen needs

Serradella (left) and woolly pod vetch and are joining a suite of pasture legumes being evaluated for their ability to provide residual nitrogen in cropping systems at Broomehill.
Photo: DPIRD and Sue Knights

Broomehill growers stand to benefit from another trial to be established as part of the Harvestable Annual Legume Options (HALO) project supported by GRDC and the WA Agricultural Research Collaboration.

Situated 300 kilometres south of Perth on the road to Albany, within an annual rainfall zone of 475 millimetres, profitable cropping has intensified in this region but there has been low adoption of viable harvestable pasture legumes.

HALO project lead Dr Ron Yates says advisers and growers have been reluctant to include pasture legumes in their systems due to a lack of perceived benefits, and the narrow choice of cultivar options. However, an informal meeting between Broomehill growers and the GRDC’s National Grower Network management saw an opportunity to address this through a customised regionally designed trial.

The HALO project, with collaborative research between Murdoch University, the Department of Primary Industries and Regional Development (DPIRD) and CSIRO, is focusing on delivering new harvestable annual pasture legumes for different soil types in low, medium and high-rainfall farming zones of WA.

“The uncertainty of nitrogen fertiliser prices, carbon emission implications and growers focusing on risk mitigation have identified the need for a pasture legume as adaptable as lupins that can provide a reliable nitrogen source in mixed-farming operations, particularly to increase grain protein levels in cereals,” Dr Yates says.

“Next year we will establish a rotational trial in the region, which will run for two years. It will not only increase knowledge of the legacy of pasture legume nitrogen residue from different pasture legumes in rotation, but also increase the presence of pasture legume agronomists in the area to raise the profile of these legumes. Particular attention will be paid to optimising nitrogen fixation, with all pasture legumes inoculated with the most-recent specific commercial rhizobia strains.”

The trial will examine the differences in nitrogen transformations between traditional and harvestable annual pasture legumes, lupins and cereals across a typical duplex soil common in the area. It is fully randomised and replicated with soil temperature loggers at the site.

We are taking a close look at the performance of hard and soft-seeded serradella, hard-seeded clover, subclover and woolly pod vetch as part of the trial to increase the pasture legume options available for growers

"The trial will assist in in developing agronomy packages for the break crop legumes – including herbicide options and legume herbage incorporation – to maximise the benefits of harvestable annual pasture legumes to both grain and forage production, and to the environment.

“In 2024, measurements will include plant establishment counts, herbage production, nitrogen natural abundance and seed yield and grain quality. These measurements will help us understand the associated production benefits of different pasture legumes to a typical farming system of the area.

“In 2025, wheat will be sown across all plots, with plots separated into three application rates of urea to assess residual pasture legume nitrogen responses. Grain yield and quality including protein will be measured. In both years we are planning field walks at the trial site with close collaboration with the Broomehill grower group.”

More information: Dr Ron Yates,

Read also: Grains projects get off the ground for research collaboration.

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