Suppressing methane emission and global warming potential from rice fields through intermittent drainage and green biomass amendment

Winter cover crops are recommended to improve soil quality and carbon sequestration, although their use as green manure can significantly increase methane (CH4) emission from paddy soils. Soil management practices can be used to reduce CH4 emission from paddy soils, but intermittent drainage is regarded as a key practice to reduce CH4 emission and global warming potential (GWP). However, significantly greater emissions of carbon dioxide (CO2) and nitrous oxide (N2O) are expected when large amounts of cover crop biomass are incorporated into soils. In this study, we investigated the effects of midseason drainage on CH4 emission and GWP following incorporation of 0, 3, 6 and 12 Mg/ha of cover crop biomass. Methane, CO2 and N2O emission rates significantly (P