Integrated nutrient management in a rice-wheat system

Abstract

The result of a 4-year study on integrated nutrient management in a rice-wheat system revealed that both rice and wheat yields continued to increase significantly with increasing NPK levels up to 100 per cent of recommended dose through fertilizers. Green manuring (GM) of jantar (Sesbania aculeata) with 50 per cent recommended dose of NPK to rice produced as much rice yield (62.7 q ha−1) as 100 per cent NPK dose through fertilizers (62.8 q ha−1). Inclusion of short duration pulse (mungbean) in the system not only produced 11.0 q ha−1 before rice transplanting but also substituted for 50 per cent of recommended NPK fertilizers in rice. Among the different organic sources of N for rice, jantar (GM) proved significantly superior to FYM and wheat cut-straw in increasing the crop yields and their nutrients uptake. The organic carbon and available nutrients content of the soil decreased considerably in control plot from their initial status. An application of fertilizers or their combined use with the organic manures increased the organic carbon status of the soil. The NPK fertilizers at 100 per cent recommended levels or more and their combined use with organic N sources also increased the available N and P by 5–22 kg and 0.8–3.8kg ha−1 from their initial values.