Effects of warming and reduced precipitation on soil respiration and N2O fluxes from winter wheat-soybean cropping systems

Abstract The effects of experimental warming and reduced precipitation on soil respiration (SR) and nitrous oxide (N 2 O) fluxes have been of increasing concern but are poorly understood, particularly in agroecosystems. A plot experiment was conducted in a winter wheat–soybean cropping system over the 2014–2016 growing seasons in southeast China. A full two factorial design was used that included treatments with crop canopy temperature increased by ~2 °C (T), 30% reduction in precipitation (P), the combined soil warming and precipitation reduction (TP), and the control under ambient conditions (C). Seasonal patterns of SR and N 2 O fluxes did not significantly differ among the treatments. Over the 2014–2016 period, soil warming significantly increased SR rates and N 2 O emissions. Compared with the control, the reduced precipitation treatment significantly decreased SR rates, but its effects on N 2 O fluxes were not pronounced. There was no interactive effect of warming and reduced precipitation on SR rates and N 2 O fluxes. Overall, our results suggest that climate warming would lead to more soil CO 2 and N 2 O emissions, potential but poorly understood changes in precipitation may thus control soil greenhouse gas emissions in a warming world.