Effect of Organic Residues with Varied Carbon-Nitrogen Ratios on Grain Yield, Soil Health and Nitrous Oxide Emission from a Rice Agroecosystem

Experiments were conducted in an attempt to study the impact of different organic residuesas fertilizers on grain yield, magnitude of nitrous oxide (N2O) emissions and soil characteristics. Five fertilizer treatments including conventional nitrogen (N) fertilizer, cow manure, rice straw, poultry manure and sugarcane bagasse were applied in the rice field during 2012. Maximum reduction in seasonal N2O emissions (10–27%) was observed under the influence of rice straw application over conventional N fertilizer. The experiment was repeated for a second season during 2013 with the same treatments for further confirmation of the results obtained during the first year of experimentation. Application of rice straw also showed a slight advantage in increasing grain yield (4.38 t ha⁻¹) over control. Important soil properties and plant growth parameters were studied and their relationships with N2O emission were worked out. Incorporation of organic residues helped in restoring and improving the soil health and effectively enhancing grain yield with reduced N2O emission from rice fields.