Nitrous oxide emissions from rice paddy: Impacts of rice straw and water management

Abstract

AbstractTypically, organic amendment additions like rice straw (RS) are used in agriculture to improve soil quality. The application of RS may influence the production of methane and nitrous oxide (N2O), which may increase the amount of accessible nutrients and organic matter (OM). When compared to farmers' practices of continuous flooding irrigation (CFI), water management (WM) techniques like alternative wetness and dryness irrigation (AWDI) in paddy rice cultivation boost water use efficiency and may result in lower greenhouse gas (GHGs) emissions. A randomized complete block design (RCBD) was employed to evaluate the impacts of WM (CFI and AWDI), RS (15.0 and 30.0 ton ha−1), and their interaction (RS*WM) on the N2O emission and rice yield in a rice paddy calcareous soil. In comparison to control, a single application of RS at 15.0 and 30.0 ton ha−1 significantly reduced N2O emissions by 16.20% and 31.40% (p < 0.01). AWDI regime increased N2O emissions by 67.0% in comparison to the CFI regime (p < 0.01). According to two tailed Pearson correlation, the correlations between AWDI and N2O emissions in the days following rice planting were significantly positive at 0.01 levels. In AWDI regime, adding RS significantly reduced N2O emissions by 18.68% and 31.55% in 15.0 and 30.0 ton ha−1 added RS, respectively, compared to solo WM treatments (p < 0.01). Both RS rates resulted in a considerable increase in biomass and rice grain while AWDI had no significant effect on them. Our study shows that AWDI saved 18.50% water in comparison with CFI regime.