Increasing wheat proteins sustainably by rotation with forage legumes

Authors

Robert J. Harrison, Department of Primary Industries and Regional Development, Western AustraliaFollow
John Gregory Howieson, Murdoch UniversityFollow
Tom Edwards, Department of Primary Industries and Regional DevelopmentFollow
Emma J. Steel, Murdoch University
Chris M. Poole, Murdoch University
Ronald J. Yates, Department of Primary Industries and Regional Development, Western AustraliaFollow

Document Type

Article

Publication Date

8-16-2023

Journal Title

Agronomy for Sustainable Development

ISSN

1774-0746 eISSN: 1773-0155

Keywords

Biological nitrogen fixation, Forage legumes, GHG emissions, Wheat gluten

Disciplines

Agronomy and Crop Sciences

Abstract

Wheat proteins provide around 20% of all human dietary protein, but their end-use qualities are determined by the form and quantity of nitrogen in the endosperm. In the developed world, there is a heavy reliance in grain production on nitrogen supplied from synthetic fertilisers, and this fertiliser can contribute up to 50% of the on-farm emissions of greenhouse gasses in agriculture. However, despite increasing rates of application of synthetic nitrogen to cereals, wheat grain protein levels, in developed nations, have been frequently failing to reach the premium grade required by the bread-making market. Here, for the first time, we report that biological nitrogen fixation from a new generation of hardseeded annual forage legumes, when grown in rotation with cereal crops, can replace fertiliser N without compromising grain protein. The forage legumes were grown in rotation with Triticum aestivum, and compared with rotations that included a fallow, or a cereal crop at three rainfed sites in Western Australia with differing soil types for 2–4 years. The wheat received low, medium and high rates of urea to indicate if forage legumes can provide sufficient nitrogen for sustainable wheat production. At all sites and years studied, we discovered that cereal grains produced following a year of forage legumes had significantly higher protein levels than when grown as part of a continuous cereal rotation. These results were achieved in combination with a reduction in on-farm emissions (by over 200 kg/ha of CO2) without compromising yield as indicated by emissions accounting. Including appropriate forage legumes in farming systems allows production of low emission intensity grain proteins in dryland farming.

Recommended Citation

Harrison, R.J., Howieson, J.G., Edwards, T.J. et al. Increasing wheat proteins sustainably by rotation with forage legumes. Agron. Sustain. Dev. 43, 56 (2023). https://doi.org/10.1007/s13593-023-00913-9