Effect of integrated nutrient management on rice-wheat yield and soil properties in a north western Himalayan region

Impact of integrated nutrient management was assessed on crop yields and soil properties under long-term experiment. Ten treatments comprising of control, inorganics viz., 50, 75 and 100% NPK and conjoint use of 50 and 75% NPK with 50 and 25% N substitution either through FYM, wheat cut straw or green manure, Dhaincha (Sesbania aculeata) during kharif (June-October) followed by 100 and 75% NPK through inorganics in rabi (November-May), respectively were imposed in rice-wheat cropping system continuously since 1991. The recommended doses in 100% N, P and K were 90:17:33 and 120:26:25 for rice and wheat, respectively. The grain yield data of both the crops have been compiled since beginning of the experiment and mean values have been given as initial, mid and final years. The results of soil samples collected at harvest of wheat (rabi 2008–09) showed improvement both in physical and chemical properties. The results further revealed that application of 50% N through FYM plus 50% NPK through chemical fertilizers to rice and 100% NPK to wheat was the best practice than rest of the treatments not only in sustaining higher crop yields, but also improving the soil properties. The highest values of pH, organic carbon, CEC, available N, P and K were recorded under treatment T where 50% NPK+50% N through FYM during kharif and 100% NPK during rabi was applied. Further, the 50% substitution of N through any of the organics proved better over 25% substitution rate.