PRODUCTIVITY OF MUNG BEAN AND SESAME GROWN ON RESIDUAL FERTILITY IN MULTIPLE CROPPING SYSTEMS

Field experiments were conducted on an Entisol from 1984 to 1987 at Bi dhan Chandra Agricultural University, West Bengal, India, to study the residual effects of N, P, and K on productivity of mung bean (Vigna r adiatus Roxb.) and sesame (Sesamum indicum L.) in irrigated multiple c ropping with rice-potato-mung bean and rice-potato-sesame cropping sys tems. The crops were grown with or without application of farmyard man ure or incorporation of crop residues. Different quantities of inorgan ic fertilizers based on locally recommended practices for fertilizatio n were applied to rice and potato and their residual effects on succee ding mung bean or sesame crops were assessed. Application of fertilize rs at a higher rate than the recommended amounts to rice and potato in the system showed no significant residual effect on yields of succeed ing mung bean or sesame compared to the yields obtained with the appli cation of N, P, and K at 100% of the recommended rate or 75% of the re commended rate with manure or residues. Any reduction in the applicati on of recommended amounts of fertilizers to rice or potato without com pensating amounts coming from other organic sources resulted in lower productivity of succeeding mung bean and sesame.