Induction of mungbean [Vigna radiata (L.) wilczek] as a grain legume in the annual rice-wheat double cropping system

A traditional approach to deal with the declining yields of rice-wheat system has been introduction of pre-rice legumes as manuring crops. however,despite the long-term beneficial effects on soil fertility and productivity of the rice-wheat system,farmers are reluctant in practicing green manuring technology. major constraints in the adoption of green manuring technology are the additional cost of green manure production and the lack of short-term benefits. an alternate approach i.e.,induction of a short-duration grain legume in the rice-wheat system appears to be more attractive as it offers short-term additional benefits to farmers and is equally beneficial in sustaining the productivity of rice-wheat system over time. present study was carried out to evaluate the induction of short-duration (maturity period,55-70 days) mungbean [vigna radiata (l.) wilczek] as a grain legume in the pre-rice niche of the rice-wheat annual double cropping system. the mungbean crop (grown without mineral n fertilizer) produced 1166 kg ha-1 of grain in addition to 4461 kg ha-1 of the manure biomass (containing 52 kg n ha-1) that was ploughed under before planting rice with urea-n applied in the range of 0-160 kg n ha-1. averaged across urea-n treatments,manuring significantly increased the number of tillers plant-1 (11% increase),rice grain yield (6% increase),grain n content (4% increase) and grain n uptake (9% increase). significant residual effects of manuring were observed on the subsequent wheat crop showing higher grain yield (21% increase),grain n uptake (29% increase) and straw yield (15% increase). the results suggested the feasibility of including mungbean in the pre-rice niche to improve the productivity of the annual rice-wheat double cropping system.