Effects of different management patterns on greenhouse gas emissions from single-season rice fields

Different cultivation practices affect both rice yield and GHG emissions. In this study, GHG emissions, environmental factors, and soil factors on an annual scale for four common single-season rice-cultivation methods were monitored and the direct and indirect drivers of GHG emissions were analysed. The results showed that there were significant differences in the average soil temperature, water content and dissolved oxygen content for the different methods used, but not in terms of the NH4+-N and NO3--N content. The highest average methane flux was obtained using the waterlogging in the non-rice season with straw return mode method (4.20 +/- 0.16 mg m-2 h-1), which was a significantly higher result than that produced by the other methods. The main factors influencing CH4 emissions was atmospheric temperature for waterlogging in the non-rice season with straw return and crayfish farming, NO3--N for waterlogging in the non-rice season without straw return, NO3--N, and NH4+-N for waterlogging in the non-rice season with straw return, and NO3--N, NH4+-N, and soil water for non-rice season with straw return. The average fluxes of both CO2 and N2O were highest with the drainage in the non-rice season with straw return treatment, but the differences between the treatments were not significant. None of the factors that were determined had a significant direct effect on CO2 emissions under either cropping system. The main factors affecting N2O emission were NH4+-N and NO3--N in the WSC treatment, NH4+-N in the waterlogging in the non-rice season without straw return treatment, and NH4+-N, NO3--N, and dissolved oxygen content in the drainage in the non-rice season with straw return treatment. The results obtained have the potential to form an important basis for the establishment of agronomic measures to reduce and control GHG emissions from rice fields.