Enhancing legume N2 fixation through plant and soil management

Abstract

Atmospheric N2 fixed symbiotically by associations between Rhizobium spp. and legumes represents a renewable source of N for agriculture. Contribution of legume N2 fixation to the N-economy of any ecosystem is mediated by: (i) legume reliance upon N2 fixation for growth, and (ii) the total amount of legume-N accumulated. Strategies that change the numbers of effective rhizobia present in soil, reduce the inhibitory effects of soil nitrate, or influence legume biomass all have potential to alter net inputs of fixed N. A range of management options can be applied to legumes growing in farming systems to manipulate N2 fixation and improve the N benefits to agriculture and agroforestry.