Tips and tactics: legumes and nitrogen fixation – Southern and Western regions (Factsheet)
This Grains Research and Development Corporation (GRDC) factsheet (first published 2017, updated 2025) explains how nitrogen fixation works in pulse and pasture legumes and provides practical guidance for growers and advisers to maximise nitrogen benefits in farming systems.For legumes to supply nitrogen (N) to the current crop and build soil N for future rotations, they must be well nodulated by root nodule bacteria (rhizobia). Effective nodulation is essential for lupin, lentil, field pea, faba bean, vetch and chickpea crops, as well as legume pastures such as medic. Roots need adequate numbers of active nodules to maximise nitrogen fixation. Nodules may develop from background soil rhizobia or from applied inoculant. Regardless of whether seed was inoculated, growers should assess nodulation in both grain and pasture legumes. This factsheet explains how to do an easy four-step ‘nod check’ using buckets, a shovel and water. It discusses the benefits of inoculation and includes troubleshooting questions to explore possible reasons for poor nodulation [PDF 6.4 MB, 8 pages].#
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