麦秆还田方式对旱地土壤综合温室效应的影响

Effects of Wheat Straw Return Ways on Integrated Global Warming Effect from Dryland Soil in North China Plain

采用静态箱–气相色谱法,研究了秸秆还田方式对华北平原旱地玉米生长季土壤温室气体(CO2、CH4和N2O)排放的影响。结果表明:小麦秸秆不同还田方式下,土壤CO2、CH4和N2O的排放动态无显著差异,但排放量因温室气体种类而异。秸秆直接还田处理的CO2、N2O排放量分别显著高于无秸秆还田、秸秆原位焚烧、生物质炭还田处理的29.7%、17.5%、31.7%和78.1%、76.3%、114.0%;而CH4排放量在各试验处理间无显著差异。从各处理的综合温室效应(GWP)来看,生物质炭还田处理的GWP比秸秆直接还田处理显著降低28.7%,而与无秸秆还田和秸秆原位焚烧处理无显著差异。考虑到作物产量变化,进一步分析表明,生物质炭还田处理温室气体强度(GHGI)比无秸秆还田和秸秆原位焚烧处理分别降低4.9%和14.9%,差异不显著,比秸秆直接还田处理显著降低36.0%。因此,在华北平原秸秆炭化生物质炭还田具有显著的综合减排作用,是一种土壤农田低碳生产的秸秆利用途径。

A field experiment was conducted to investigate the effect of wheat straw return ways on maize production and greenhouse gases（GHGs） mitigation in North China Plain. GHGs emission was measured using static-chamber gas chromatography method. Five treatments were established, including CK（no chemical fertilizer＋no straw as control）, NR（chemical fertilizer＋no straw）, SR（chemical fertilizer＋straw）, AR（chemical fertilizer＋straw as ash）, BR（chemical fertilizer＋straw as biochar）. The results showed there was no significant change in the dynamics of greenhouse gases emission from soil among different treatments, but significant in the amount of emission, which was related to types of greenhouse gases. The amount of CO2 emission in the treatment of SR increased by 29.7%, 17.5% and 31.7% compared to the treatment of NR, AR and BR, and the amount of NO2 emission in the treatment of SR increased by 78.1%, 76.3% and 114.0% compared to the treatment of NR, AR and BR, respectively, but there was no significant difference in the amount of CH4 emission among the all treatments. The GWP was decreased by 28.7% in the BR treatment than that in the SR treatment, but no difference among the BR, NR and AR treatment. Considering the result of corn yield into account, the GHGI was decreased by 4.9% and 14.9% for the treatment of BR than the treatments of NR and AR, and significantly was decreased by 36% for the treatment of BR than the reatment of SR. Therefore, the conversion of crop straw to biochar as an addition to dryland could be an effect way of increasing maize yield and mitigating climate change.