Soil Fertility Changes after Long-Term Application of Organic Manures and Crop Residues under Rice-Wheat System

Abstract

A long-term field experiment on integrated management of FYM, green manure (GM) and crop residues with inorganic fertilizers in rice-wheat system is in progress at the Punjab Agricultural University, Ludhiana, since 1993. The effect of organic materials and inorganic fertilizers on soil properties and grain yield of rice and wheat was studied after 8 years of cropping cycle on a loamy sand. The incorporation of crop residues along with 50% NPK and FYM or GM contributed towards meeting 50% NPK requirement of rice. Long-term application of crop residues and organic manures increased the soil organic C content of soil. The combined use of crop residues, organic amendments and chemical fertilizers significantly increased the availability of N, P, K, S and micronutrients in soil over chemical fertilizers alone.