稻草还田和冬种绿肥对华南双季稻产量及稻田CH_4排放的影响

Effects of Rice Straw and Winter Green Manure Incorporations on Grain Yields and Methane Emissions of Double-Season Rice(Oryza sativa) Field in South China

以常规稻合丰占为材料,开展田间裂区试验,主因素设稻草不还田和全部稻草还田2种处理,副因素设冬闲和冬种绿肥并全部还田2种处理,研究稻草还田和冬种绿肥及其互作对华南双季稻产量和稻田CH4排放的影响,以期为华南双季稻低碳高产栽培提供指导。结果表明:稻草全量还田显著提高水稻产量,平均增产4.8%,主要原因是稻草还田促进水稻的干物质积累,增加了每穗粒数,但稻草还田极显著增加稻田CH4排放量,平均增幅为41.8%;冬种紫云英绿肥显著提高水稻产量,平均增产3.6%,同时稻田CH4排放量也增加,但差异没有达到显著水平。无论是对水稻产量还是稻田CH4排放,稻草还田和冬种绿肥处理之间的互作效应均不显著,表明二者的作用是相互独立的。综合考虑水稻产量和CH4排放的表现,冬种紫云英绿肥可作为华南双季稻低碳高产栽培的重要措施。

Rice straw and winter green manure incorporations are two common practices to improve soil fertility and increase grain yields in rice farming systems in South China. However, they may also enhance CH4 emissions from the paddy fields due to carbon inputs. This experiment was designed to investigate the effects of rice straw and winter green manure additions on grain yields and methane emissions of paddy fields with double-season rice in South China. Compared to zero-straw treatment, incorporating whole rice straw significantly enhanced both dry matter production and spikelets per panicle, and thus the yield of rice grains by 4.8%. Meanwhile, straw incorporation significantly stimulated CH4 emissions, which was 41.8% higher than in zero-straw treatments. Applying winter green manure significantly increased grain yield by 3.6%, but did not significantly affect CH4 emissions, compared to the no green manure control. There were no significant interactions between straw incorporation and green manure. Our results suggest that winter green manure would be a promising practice for low-carbon emission and high-yield rice production in South China.