Projected background nitrous oxide emissions from cultivable maize and rice farmland in China

Climate change is expected to have a major impact on agriculture in China. It affects agricultural background nitrous oxide emissions (BNE) through warming or cooling and precipitation changes, but the related mechanisms remain poorly understood. Therefore, using projections of future climate derived from a multi-model ensemble under three representative concentration pathway scenarios (RCP2.6, RCP4.5, and RCP8.5), a grid-based spatial analysis was conducted to investigate the agricultural BNE by empirical statistical models and simulated suitable cultivation areas of rice and maize in China for 2006-2100. The results indicated that the spatio-temporal variation of BNE was dominated by temperature and the interaction effect of temperature and precipitation may also play an important role. Under the high-emission scenario (RCP8.5), the greater warming caused the potential BNE area of maize and rice to slightly migrate northward and the high-emission area was concentrated in southeastern China. The total BNE showed an increasing trend over time, from 120.59 +/- 0.69 to 142.42 +/- 0.78 Gg N a(-1) during the 21st century, driven by the synthetic action of these climatic factors. The findings of this study may provide reference for predicting future agricultural BNE and formulating appropriate measures to mitigate global warming.