On-farm trials of the effect of introducing a summer green manure of mungbean on the productivity of a rice-wheat cropping system

Fourteen field trials were conducted on farmers' fields in five villages of the Union Territory of Delhi, India during 1995-96 and 1996-97 to study th e effect of introducing a crop of summer mungbean on the productivity of a rice-wheat cropping system. Timely sown summer mungbean yielded 0.4-1.3 t/h a protein-rich grain and, on average, increased rice yields by 0.5-0.9 t/ha and the yields of the succeeding wheat by 0.4-0.7 t/ha. The yield response of rice to the summer mungbean crop was greater when less urea-N fertilize r was applied, and N applied to the rice did not decrease the residual effe ct of the summer mungbean on the succeeding wheat. The increase in total pr oductivity of rice-wheat cropping system due to summer mungbean ranged from 0.3 to 2.6 t/ha with an average of 1.6 t/ha.