Effect of current and future temperature on CH4 and N2O emission from rice soil ecosystem.

An investigation to assess the greenhouse gases (GHG's) fluxes in rice cultivation under current and elevated temperature was carried out at Agro Climate Research Centre, Tamil Nadu Agricultural University, Coimbatore, during rabi season (November 2014 - March 2015). This experimentation was carried out with two temperature levels viz., current temperature at open environment and +2°C elevated temperature at Temperature Controlled Chamber. During the experimentation, GHG emission rate was evaluated. The nitrous oxide emission attained maximum at 15 DAT followed by 45 DAT and then decreased towards maturity. The methane emission rates increased with age of the crop, but attained maximum at harvesting stage. The methane emission rates from rice crop grown under open environment were higher than elevated temperature. The nitrous oxide emission rates from rice crop grown under +2°C elevated were higher than open environment. Methane is normally translocated through rice plants and the higher biomass generation under open environment led to higher methane translocation. The nitrous oxide emission was normally through microbial activity and the higher microbial activity was in elevated temperature led to more nitrous oxide emission. The tradeoff between CH₄ and N₂O emission has to be analyzed critically and developing appropriate nutrient and water management strategies and maintaining the soil redox potential at an intermediate range (-100 to +200 mV) would minimize emissions of both CH₄ and N₂O. Overall, the data have shown clear evidence that rice cultivation in future reduced methane emission but increase nitrous oxide emission. [ABSTRACT FROM AUTHOR]