Grain Yield, Yield Components, Soil Fertility, and Biological Activity under Organic and Conventional Rice Production Systems

A field experiment was conducted for 2 years on a clayey Vertisol to compare the organic and conventional methods of rice farming. Two main plot treatments were with and without plant protection and four subplot treatments were (1) control (CON); (2) inorganic fertilizers (CF); (3) organics (OF), and (4) inorganics + organics (integrated nutrient management, INM). The organics were green manure, paddy straw, and poultry manure. After 2 years, the main plot effects were not significant in terms of crop productivity though there was a reduction in soil biological parameters. Increase in grain yield was larger with inorganics and INM as compared to the organics because of the higher panicle number. However, organics increased the microbial populations, biomass carbon, nitrogen, enzyme activities, and soil fertility as compared to inorganics. Thus, organics improved the nutrient availability by influencing the soil biological activity although it did not reflect in greater yields.