Long-term Effect of Green Manuring and Farmyard Manure on Yield and Soil Fertility Status in Rice-Wheat Cropping System

A long-term integrated nutrient management experiment was conducted under rice-wheat cropping system to assess the direct and residual effect of green manures on crops with and without farmyard manure (FYM). The highest grain and straw yields of rice and wheat were obtained with the application of 100% NPK + green gram + 5 t FYM each year. Combined application of 100% NPK + green gram + 5.0 t FYM each year gave significantly higher available N, P, K and higher content of DTPA-extractable Zn, Fe, Mn and Cu in post-harvest soil at the end of six years cycle. The DTPA-extractable Zn was found to be higher in the treatment combination of 100% NPK + 10 kg Zn ha−1 for each of the 5 crops. It is concluded that integrated application of 100% NPK + greengram + 5.0 t FYM was the most effective treatment in meeting the micronutrient requirements of rice and wheat crops.