Effect of improved nutrient management on grain yield of rice (Oryza sativa) and soil health under organic management

A field experiment was conducted at ICAR Research Complex for Goa, Goa, for 5 years during 2009–13, to standardize different nutrient sources for organic production in 3 varieties of rice (Oryza sativa L.) in split-plot design with 3 replications. Rice variety ‘Karjat 3’ gave significantly higher grain yield (4.09 t/ha) than either ‘Revathy’ (3.49 t/ha) or ‘Pusa Sugandh 5’ (2.47 t/ha). Application of FYM resulted in at par grain yield (3.66 t/ha) with recommended fertilizers (3.87 t/ha), while Gliricidia with Eupatorium sp. recorded 90% of the grain yield (3.47 t/ha) and 86% of the straw yield (6.88 t/ha) obtained with recommended fertilizers (3.87 and 7.99 t/ha, respectively). Higher increase in soil organic carbon was observed with the application of FYM over 5 years (1.24%). Levels of P and K in the soil were appreciably reduced after 5 rice crops with the application of any of the nutrient sources. Application of vermi-compost influenced higher buildup of both bacterial and actinomycetes growth in soil (24.72 × 10⁵ CFU/g and 53.39 × 10⁴ CFU/g, respectively). Application of Gliricidia with Eupatorium sp. recorded at par net returns (40, 000/ha) by recording 96.5% net returns of the recommended fertilizers (41, 460/ha).