秸秆还田对稻麦两熟高产农田净增温潜势影响的初步研究

对长江下游稻麦两熟农田生态系统2009—2010年的CH4和N2O排放以及土壤碳固定进行了分析,初步研究了秸秆还田对稻麦两熟高产农田净增温潜势的影响。结果表明,秸秆还田对稻麦两熟高产农田周年CH4和N2O排放总量、土壤碳固定量以及净增温潜势均有显著或极显著影响：秸秆还田条件下周年CH4、N2O排放总量分别为394 kg CH4.hm-2、2.39 kg N2O.hm-2,土壤碳固定量、净增温潜势分别为1.14 t C·hm-2、6383 kg CO2-equivalents·hm-2;较秸秆不还田增加CH4排放总量152%、减少N2O排放总量14%、增加土壤碳固定量531%、增加净增温潜势57%。以上结果表明,秸秆还田使短期内稻麦两熟高产农田的温室效应明显提高,但其长期效果如何还有待观测。

Preliminary Study on Effect of Straw Incorporation on Net Global Warming Potential in High Production Rice-Wheat Double Cropping Systems

Atmospheric carbon dioxide（CO2）, methane（CH4） and nitrous oxide （N20） are most potent long-lived greenhouse gases that con- tribute to global warming. Although several agricultural practices are available to targeting a specific greenhouse gas（CH4 or N20 ） mitigation or soil organic carbon sequestration（ SOCS ）, however, the effects of agricultural managements on global warming potential（GWP） are current- ly poorly understood. This paper investigated the effect of straw incorporation on annual CH4 and N20 emissions, SOCS and net GWP of a high production rice-wheat double cropping system in 2009--2010, in the lower reaches of the Yangtze River. The results showed that annual to- tal CH4 and N20 emissions, SOCS and net GWP were significantly influenced by straw incorporation. Annual total CH4 and N20 emissions, SOCS and net GWP for straw incorporation were 394 kg ·hm-2, 2.39 kg-hm-2, 1.14 t C ·hm-2, 6383 kg CO2-equivalents -hm-2, respectively. Compared with no straw incorporation, straw incorporation increased annual total CH4 emissions, SOCS and net GWP by 152%, 531% and 57%, respectively, decreased annual total N20 emissions by 14%. The results of this preliminary study suggested that straw incorporation could significantly increase greenhouse gases emissions in high production rice-wheat double cropping systems, at least in the short term.