Simulation of Nitrous Oxide Emission and Mineralized Nitrogen under Different Straw Retention Conditions Using a Denitrification-Decomposition Model

Straw retention has been adopted worldwide to increase crop production and it has also been shown to reduce nitrous oxide (N2O) emission from agricultural soils. However, it is difficult to accurately predict N2O emission under different straw retention methods without a long-term experiment. This study used data from the maize planting season in the Griffith region, Australia, to test whether the denitrification-decomposition (DNDC) model can simulate the rate, annual amount, and pattern of N2O emission. The sensitivity to several important factors which may affect N2O emission was analyzed. The research investigated whether the DNDC model can be used to determine the best straw retention method to reduce N2O emission. The results were as follows: (1) The DNDC model could be used to simulate soil and climate conditions of Griffith region. The correlation coefficients of simulated and observed water-filled pore space and temperature were 0.9532 (n = 126) and 0.9781 (n = 365), respectively; (2) the simulation values of 300N-burn and 300N-incorporate for a year were 12.96 and 8.08 kg N ha(-1) year(-1) and the emission factors were 3.31 and 1.77, respectively; (3) the emission reduction effect and mineralized N accumulation of straw incorporation were better compared to burnt straw, using the DNDC model. The correlation coefficients of simulated and observed daily values of 300N-burn and 300N-incorporate were 0.8743 and 0.8023, respectively; (4) the amount and frequency of nitrogen fertilizer application, irrigation frequency, and soil texture could affect N2O emission, whereas soil pH and soil bulk density did not.