Faced with the great challenge of food demand and environmental pollution, optimizing agricultural practices can potentially balance food security and environmental protection. In this study, the DeNitrification-DeComposition (DNDC) model was applied to explore the effect of wheat-based management strategies on crop productivity and greenhouse gas emissions in the wheat-maize system. The DNDC model was tested against crop yield, daily nitrous oxide (N2O) fluxes, and cumulative N2O emissions determined from field measurements in a typical winter wheat-summer maize cropping system. Model evaluations demonstrated a good agreement between the observations and simulated crop yield (4.4%≤NRMSE≤8.0%), daily N2O fluxes (0.68 ≤ d ≤ 0.88), and cumulative N2O emissions (4.9%≤NRMSE≤11.9%). By adopting sensitivity analysis, the DNDC model then assessed the impacts on crop yield and cumulative N2O emissions of multiple management practices from the winter wheat season. Delaying the sowing date from October 7 to November 4 reduced annual yield by 1.9%, while cumulative N2O emissions were increased by 10.4%. Furthermore, postponing the supplementary irrigation date from April 1 to May 20 decreased annual yield by 2.4% without affecting cumulative N2O emissions. An N fertilizer rate of 120-150 kg N ha-1 was able to reduce N usage and cumulative N2O emissions without sacrificing annual yield. Despite an improvement in the annual yield at the 0-30 cm tillage depth by 2.9%, cumulative N2O emissions increased by 11.6%. The results suggest that sowing in early October, applying supplementary irrigation in early April, an N fertilizer rate of 120-150 kg N ha-1, and no-tillage from the winter wheat season can improve crop yield and mitigate N2O emissions. This is conducive to the synergism of agricultural production and environmental sustainability.
Keywords: Management practice; N(2)O emission; Process-based model; Sensitivity analysis; Yield.
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