Can we breed pulses that fix more nitrogen—and leave more value for the next crop? Australian research is exploring how improved nitrogen fixation in chickpeas, lentils, faba beans, lupins, field peas and mungbeans could benefit farming systems.
In this episode of In The Paddock — Field Notes, farmer and agronomist Martin Murray examines the breeding work, explains the biology and asks what it could mean for growers’ rotations and fertiliser budgets.
First, though, a reality check: pulses don’t automatically leave a huge nitrogen surplus. They use nitrogen to grow and produce grain, and harvesting that grain removes much of it. Nitrogen fixed by a pulse crop is not the same as nitrogen available to the following wheat or canola crop.
IN THIS EPISODE
• How rhizobia and root nodules help pulses access atmospheric nitrogen.
• Why crop growth and soil nitrate affect nitrogen fixation.
• The Australian research programme targeting six pulse crops.
• How breeders could combine useful genetic traits through “haplotype stacking”.
• Why a target of at least 10% improved fixation does not mean a 10% fertiliser saving.
• Grain nitrogen removal, residual benefits and the importance of the whole rotation.
• What needs proving before improved genetics reach commercial paddocks.
Better nitrogen fixation could be valuable—but it must work alongside competitive grain yield, disease resistance and suitable maturity. We explore the questions farmers should ask before assigning a dollar value to the potential benefits.
HAVE YOUR SAY
If two pulse varieties yielded the same, would stronger nitrogen fixation influence your choice? What evidence of a benefit to the following crop would convince you?
MORE FROM IN THE PADDOCK
Practical agronomy, Australian farming and emerging agricultural research:
Follow In The Paddock for more Field Notes episodes, and share this episode with a grower or agronomist interested in pulse crops, soil fertility and nitrogen management.
SOURCES & FURTHER READING
GRDC GroundCover — Stacking the genetics of nitrogen fixation in pulses:
Australian National University — Pulse nitrogen fixation research:
NSW DPIRD — Nitrogen benefits of chickpea and faba bean:
Evans and colleagues (2001) — Grain-legume nitrogen balances and contributions to wheat nitrogen uptake:
https://digital.library.adelaide.edu.au/items/6baad1e6-1f3f-495e-884f-7091a2b0d617/full
Pulse Australia — Environmental benefits and nitrogen removal in grain:
https://www.pulseaus.com.au/using-pulses/environment
Research checked 26 October 2026. Improvement targets are research goals, not guaranteed outcomes or paddock-specific fertiliser recommendations. Historical trial findings illustrate variability; the worked nitrogen budget is hypothetical. Project completion dates are not confirmed commercial variety release dates.
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