稻田CH4和N2O综合排放对控制灌溉的响应

为了揭示水稻控制灌溉对稻田CH4和N2O综合排放的影响,该文采用静态暗箱-气相色谱法对控制灌溉稻田CH4和N2O排放进行原位观测,分析稻田CH4和N2O综合排放对控制灌溉水分调控的动态响应。结果表明,控制灌溉稻田CH4排放通量多低于常规灌溉稻田,且主要集中在水稻分蘖前期,峰值出现在土壤脱水后第1～2d,排放总量较常规灌溉稻田减少81.2%～82.8%;N2O排放通量多高于常规灌溉稻田,峰值出现在肥后且土壤脱水后3～4d,排放总量较常规灌溉稻田增加了121.8%～144.3%。控制灌溉稻田CH4和N2O的综合全球增温潜势较常规灌溉稻田显著减少(p<0.05),减少幅度为15.0%～34.8%。控制灌溉显著降低了稻田CH4和N2O的综合温室效应。

CH4 and N2O emissions response to controlled irrigation of paddy fields

In order to study the effects of controlled irrigation on variations of CH4 and N2O emissions from paddy fields, CH4 and N2O emissions from paddy fields under controlled irrigation were investigated by the method of static chamber/gas chromatography. The results showed that CH4 emissions from controlled irrigation paddy fields were lower than those from traditional irrigation paddy fields during most of the rice growing season. The high CH4 emissions from controlled irrigation paddy fields were mainly observed during the former tillering period of rice, and the peaks were observed 1-2 days after soil dehydration. Compared with the traditional irrigation paddy fields, cumulative emission of CH4 from controlled irrigation paddy fields reduced by 81.2%-82.8%. The N2O emissions from controlled irrigation paddy fields were mostly higher than those from traditional irrigation paddy fields, and the peaks were observed 3-4 days after soil dehydration. Compared with the traditional irrigation paddy fields, cumulative emission of N2O from controlled irrigation fields increased by 121.8%-144.3%. However, the integrative global warming potential of CH4 and N2O on a 100-year horizon was significantly decreased by 15.0%-34.8% in the controlled irrigation paddy fields (p<0.05). These results suggest that controlled irrigation can significantly mitigate the integrative greenhouse effect caused by CH4 and N2O from paddy fields.