ABSTRACT
Grain legumes (GLs) are not only important food and feed sources; they also play a major role in the sustainability and productivity of cropping systems (Siddique et al., 2008, 2012). GLs contribute to cropping system diversity when grown with crops of other plant families (e.g. Gramineae), disrupting the pest and disease cycles that develop with continuous cropping of the same species. If effectively nodulated, they can significantly enhance the nitrogen (N) dynamics of the cropping system, firstly by fixing atmospheric N to meet their own needs, and thus not relying on inorganic N fertilizer or depleting soil N, and by leaving residual N for following crops (Kumar Rao et al., 1998). Decaying legume residue, above and below ground, can enhance soil organic matter (Barrios et al., 1996), but the extent of net gain or loss in available soil N for a following crop depends on the degree of N sequestration by that residue (Kumar and Goh, 2000). Further, some GLs can release sparingly available soil phosphorus (P) to increase the available P pool of the entire cropping system (Nuruzzaman et al., 2005).
