Productivity and economics of rice (Oryza sativa)-wheat (Triticum aestivum) cropping system under integrated nutrient-supply system in recently reclaimed sodic soil

A field experiment was conducted during the rainy and winter seasons of 2001-04 to study the influence of integrated nutrient-supply system, comprising inorganic fertilizers and organic manures on the soil-fertility status, productivity and economics of rice (Oryza sativa L.)-wheat (Triticum aestivum L. emend. Fiori & Paol.) cropping system. Three organic manures @ 10 tonneslha, viz. farmyard manure (FYM), Sesbania canabina (Retz.) Pers. (dhaincha) and cut rice straw were added at 50 and 100% of the recommended doses of NPK fertilizers. The green-manure dhaincha [Sesbania cannabina (Retz.) Pers. syn, S. aculeata] applied with 100% of recommended dose of NPK fertilizers gave the maximum yield of rice as well as wheat crop. This treatment also gave the highest net return and benefit : cost ratio and produced significantly higher biomass in terms of rice- equivalent yield. The total uptake of N, P, K and Zn by both the crops increased significantly with the application of fertilizers or their combined use with organic manures. Among the organic manures the overall performance of green-manure was the best, followed by farmyard manure and cut rice straw. Application of farmyard manure and cut rice straw as well as green-manuring in rice and wheat significantly improved the available N, P, K and Zn status of the soil.