Rice straw and winter green manure can help improve soil fertility and increase rice yields in South China. Adding rice straw boosted grain yields by 4.8% but also increased methane emissions by 41.8%. Winter green manure increased grain yields by 3.6% without affecting methane emissions significantly. Combining straw and green manure did not show any significant interactions. Winter green manure seems to be a good option for reducing carbon emissions and increasing rice production in South China.