The effect of incorporation of mungbean residue on the productivity of rice

Field experiments were conducted at Jessore and Dinajpur representing two diverse agro-climatic conditions of Bangladesh to evaluate effect of incorporating mungbean residue on the following rice crop in cereal-cereal-legume cropping system. In the system, mungbean was planted after the harvest of wheat. Mungbean pods were harvested by hand pickings and stubbles were plowed down and mixed with the soil before starting the next rice crop. Mungbean biomass was mixed with the soil. Aman rice seedlings (cv. BR 11 in Jessore and BRRIdhan 39 in Dinajpur) were transplanted after the harvest of mungbean. The amount of mungbean stubbles plowed down varied between 2.24 and 2.36 t ha(-1) in Jessore and 2.70 and 2.86 t ha(-1) in Dinajpur. In both Dinajpur and Jessore, rice crop received 0, 25, 50, 75 and 100% of the recommended fertilizer level with and without addition of mungbean residue. Benefit of incorporating mungbean stubbles on the growth and productivity of the succeeding rice crop varied greatly between the locations. In Jessore, growing mungbean in rice-wheat system generally tended to increase yield of rice compared to that of rice-wheat system although the difference was not statistically significant. In Dinajpur, application of 75% of recommended N plus mungbean biomass produced the highest yield of rice (4.58 t ha(-1)). However,integrating mungbean biomass without N fertilizer application resulted in the lowest yield (3.42 t ha(-1)) of rice. Therefore, both organic and inorganic sources of N are essential in sustaining the yield of modern rice in a multicrop system especially in soils with low fertility.