Thirty-one Years Study of Integrated Nutrient Management on Physico-Chemical Properties of Soil Under Rice-Wheat Cropping System

Long-term sustainability is the concern of today's agriculture. A long-term field experiment (since 1983) comprising of 14 treatments with different combinations of inorganic (NPK) and organic fertilizers (such as farmyard manure, wheat cut straw andSesbania aculeateas green manure) was conducted to evaluate their effect on soil physico-chemical properties under a rice-wheat system. There was significant (P< .05) reduction in bulk density and soil strength but significant (P< .05) increase in infiltration rate and water retention with the use of organic manures along with chemical fertilizers. Organic C, nitrate-N, ammonical-N, and nutrient content were significantly (P< .05) higher in integrated nutrient management treated plots as compared to control. The highest carbon sequestration rate over the 3 decades was recorded in T-6, i.e., 50% recommended NPK dose through fertilizers + 50% N through FYM inkharifand 100% recommended NPK dose through fertilizers inrabi(0.29 Mg C ha(-1) year(-1)) as compared to chemically fertilized plots T-5, i.e., 100% recommended NPK dose through fertilizers (0.13 Mg C ha(-1) year(-1)). A positive and significant correlation was observed between organic carbon and soil physico-chemical properties barring bulk density, soil strength, pH, and electrical conductivity. The results clearly suggest that integrated use of balanced chemical fertilizers in combination with organic manures on long-term basis improves soil physico-chemical properties and soil carbon sequestration thereby having the potential to enhance soil sustainability.