Greenhouse gas emissions from a wheat–maize double cropping system with different nitrogen fertilization regimes

Here, we report on a two-years field experiment aimed at the quantification of the emissions of nitrous oxide (N2O) and methane (CH4) from the dominant wheat–maize double cropping system in North China Plain. The experiment had 6 different fertilization strategies, including a control treatment, recommended fertilization, with and without straw and manure applications, and nitrification inhibitor and slow release urea. Application of N fertilizer slightly decreased CH4 uptake by soil. Direct N2O emissions derived from recommended urea application was 0.39% of the annual urea-N input. Both straw and manure had relatively low N2O emissions factors. Slow release urea had a relatively high emission factor. Addition of nitrification inhibitor reduced N2O emission by 55%. We conclude that use of nitrification inhibitors is a promising strategy for N2O mitigation for the intensive wheat–maize double cropping systems. ► Impacts of N regimes on GHGs from a double cropping system were investigated in the field. ► N2O emission accounted for 0.39% of annual urea-N input. ► Nitrification inhibitor reduced N2O emission by 55% over the rotation. ► Slow release urea increased annual N2O emission compared with conventional urea. ► N fertilization slightly inhibited soil CH4 uptake. Impacts of different nitrogen regimes on N2O emission and CH4 uptake in a double cropping system were investigated in the field.