SUSTAINABLE NITROGEN MANAGEMENT IN RICE BASED CROPPING SYSTEM

Field experiments were conducted in the wetland for two consecutive years 2002 – 2003 and 2003 – 2004 to investigate the performance of greengram, clusterbean, fieldbean and cowpea as preceding crops to rice and effectiveness of their crop residues incorporation, farm yard manure and fertilizer on performance of rice and on succeeding groundnut crop. Among the four short duration leguminous crops tried preceding to rice, fieldbean produced the highest the quantity of biomass and crop residues. Incorporation of fieldbean crop residues was found to be superior to any other crop residue incorporation with regard to growth and yield of rice as well as nutrient uptake. Post-harvest soil fertility status with regard to organic carbon, available nitrogen and potassium was superior with incorporation of fieldbean crop residues. Supply of 100 per cent N through fertilizer to rice was found to be superior to any other nitrogen management practices, with regard to growth and yield as well as nitrogen uptake of rice. Incorporation of fieldbean crop residues to preceding rice has recorded the highest yield attributes and pod yield of groundnut. Growth, yield attributes and pod yield of groundnut were the highest with the supply of 100 per cent of nitrogen thorough FYM to preceding rice.