Simulating N_2O emissions from maize-cropped soil and the impact of climatic variations and cropland management in North China Plain

摘要

The Water and Nitrogen Management model (WNMM) was applied to simulate N_2O emissions from a semi-arid and maize-cropping system on a loam soil at Yuci in the North China Plain (NCP) from May 2007 to September 2007. WNMM satisfactorily simulated cropgrowth, soil water content and soil temperatures at depth and N_2O emissions from the soil, compared with the field observations during calibration and validation. About 89% of total N_2O emissions were estimated as nitrification-induced, according to WNMM simulation for this semi-arid and intensively cultivated maize-cropped soil. The calibrated and validated WNMM was then deployed to simulate N_2O emissions from this soil from 1951 to 2007 for nine management scenarios of N fertiliser application at Yuci. This sensitivity test found that the annual N_2O emissions for this system were significantly correlated to annual N fertiliser application rate (r=0.81) and maize yield (p=0.43). Based on this 57-year simulation, multivariate regression models forestimating annual N_2O emissions were developed to account for climatic variation (including annual solar radiation and rainfall) for this semi-arid and intensively cultivated maize-cropping system in the NCP.