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

Abstract

A field experiment was carried out at Varanasi for two years (2005-2007) to study the effect of organic nutrient sources on yield, nutrient uptake and soil properties of rice (Oryza sativa L.) based cropping sequence. Seven rice-based cropping sequences viz. rice-potato (Solanum tuberosum L.)-onion (Allium cepa L); rice-green pea (Pisum sativum var. hortense)-onion; rice-potato-cowpea (Vigna unguiculata subsp. sesquipedalis); rice-green pea-cowpea; rice-rajmash (Phaseolus vulgaris L.)-onion; rice-rajmash-cowpea and rice-maize (Zea mays L.)-cowpea were assigned to main plots and three treatments of nitrogen application viz. control; organic manure; organic manure + biofertilizer were allotted to sub plots. Highest rice equivalent yield (35.57 t/ha), monetary net returns (268.7×103/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 rice-potato-onion 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.