CH₄ and N₂O Emission and Grain Yield Performance of Three Main Rice-Farming Patterns in Central China

This study focuses on the development of more cropping systems in response to global warming and food security concerns. A two-year field experiment (2017-2018) was conducted to investigate the effects of greenhouse gases (GHGs), soil environmental factors and yield on traditional double-cropping rice (DR), maize rice (MR) and ratooning rice (Rr). The results showed a significant annual effect of temperature and rainfall on GHG emissions under different cropping systems. Annual CH4 emissions under MR and Rr were significantly lower than under DR. Compared to DR, the highest cumulative N2O emissions were observed in MR (14.9 kg & BULL;ha(-1)) with a reduction of 23.7% in Rr. In addition, the upland crops significantly reduced CH4 emissions for late rice, while N2O emissions increased by 20.6%. Compared with DR and Rr, global warming potential (GWP) and greenhouse gas intensity (GHGI) were significantly lower for MR (p < 0.05). Meanwhile, the annual yield of MR (16.40 t & BULL;ha(-1)) was 8.1% and 2.4% higher than that of DR and Rr, respectively. This study further found that soil temperature and NH4+-N content were positively correlated with CH4 and N2O emissions, and soil moisture was positively correlated with N2O emission. Thus, we concluded that MR has the greatest potential to improve crop yield and mitigate GHG emissions in central China.