Effect of organic nutrient sources on yield, nutrient uptake and soil biological properties of rice (Oryza sativa)-based cropping sequence

A field experiment was carried out at Varanasi for two years (20052007) to study the effect of organic nutrient sources on yield, nutrient uptake and soil properties of rice (Oryza sativa L.) based cropping sequence. Seven ricebased cropping sequences viz. ricepotato (Solanum tuberosum L.)onion (Allium cepa L.); ricegreen pea (Pisum sativum var. hortense)onion; ricepotatocowpea (Vigna unguiculata subsp. sesquipedalis); ricegreen peacowpea; ricerajmash (Phaseolus vulgaris L.)onion; ricerajmashcowpea and ricemaize (Zea mays L.) cowpea were assigned to main plots and three treatments of nitrogen application viz. control; organic manure; or- ganic manure + biofertilizer were allotted to sub plots. Highest rice equivalent yield (35.57 t/ha), monetary net re- turns ( 268.7103/ha), production efficiency (96.81 and 98.11 kg/ha/day) and irrigation efficiency (504.8 and 511.6 kg/ha-cm) were found under ricepotatoonion cropping sequence. Among the organic treatments, the highest rice equivalent yield (35.3 t/ha), production efficiency (95.7 and 97.8 kg/ha/day), irrigation efficiency (515.7 and 527.4 kg/ha-cm) and soil biological indictors like dehydrogenase activities, urease activities, soil microbial biomass carbon and soil microbial biomass nitrogen were obtained under organic nutrient management combined with biofertilizers.