早稻秸秆原位焚烧对红壤晚稻田CH4和N2O排放及产量的影响

选取湖南双季稻田为研究对象，采用静态箱-气相色谱法对晚稻田在常规施肥（NPK）、常规施肥+秸秆原位焚烧（NPK+SB）处理下的CH4和N2O排放通量进行观测，同时根据设定参数对秸秆焚烧排放的CH4和N2O进行估算。结果表明，晚稻生长期间NPK和NPK+SB 处理的CH4排放量差异很小，秸秆焚烧会增加N2O排放22.8%，但差异不显著（p＞0.05）。两种施肥方式下N2O排放峰值都出现在追肥后的土壤水分饱和时期而晒田期排放很少。据估算秸秆焚烧排放的CH4和N2O分别占NPK+SB处理总排放的4.27% 和17.31%。NPK+SB处理单位产量的全球增温潜势比NPK处理高22%。综合考虑生产效应和环境效应，水稻秸秆焚烧不是明智的选择。

Influence of early rice straw burning on CH4 and N2O emissions and grain yield of later rice fields in red soil

By using the method of static chamber-gas chromatograph technique, CH4 and N2O emission fluxes from later rice fields in 2009 were studied under the conventional chemical fertilizer (NPK) and conventional chemical fertilizer + rice straw burning (NPK+SB), while CH4 and N2O emission from rice straw burning was calculated by default value. The results showed that CH4 emissions during rice growing season were very similar in both treatments, meanwhile, N2O emission increased by 22.8% than former, but the difference was not significant at 0.05 level. The highest N2O emission occurred in the period of soil saturation moisture after top-dressing both in two treatments. CH4 and N2O emissions from rice straw burning represented 4.27% and 17.31% of total emissions in NPK+SB respectively. The global warming potential per unit rice grain of NPK+SB was 22% more than NPK. Rice straw burning should be avoided judged comprehensively by consideration of economic and environmental effects.