保护性耕作对后茬冬小麦土壤CO2和N2O排放的影响

为研究保护性耕作对后茬冬小麦土壤CO2和N2O排放的影响,在前茬进行常规耕作(T)、免耕(NT)、免耕+秸秆覆盖(NTS)、常规耕作+秸秆施用(TS)这4种处理,采用静态箱-气相色谱法分析土壤CO2和N2O排放通量.结果表明,保护性耕作没有改变后茬土壤CO2和N2O排放的季节性规律,对冬小麦生物量无明显影响;保护性耕作显著减少了土壤CO2和N2O累积排放量.与T相比,TS、NT、NTS的全生育期土壤CO2累积排放量分别降低了5.95%(P=0.132)、12.94%(P=0.007)和13.91%(P=0.004),土壤N2O累积排放量分别减少了31.23%(P=0.000)、61.29%(P=0.000)和33.08%(P=0.000).本研究表明免耕与秸秆施用能减少后茬作物生长季土壤的CO2和N2O排放量.

Effects of Conservation Tillage on Soil CO2 and N2O Emission During the Following Winter-Wheat Season

In order to study the effect of conservation tillage on soil CO₂ and N₂O emissions in the following crop-growing season, field experiments were conducted in the winter wheat-growing season. Four treatments were conventional tillage (T), no-tillage with no straw cover (NT), no-tillage with straw cover (NTS), and conventional tillage with straw incorporation (TS), respectively. The CO₂ and N₂O fluxes were measured using a static chamber-gas chromatograph technique. The results showed that in the following winter wheat-growing season, conservation tillage did not change the seasonal pattern of CO₂ and N₂O emission fluxes from soil, and had no significant effect on crop biomass. Conservation tillage significantly reduced the accumulative amount of CO₂ and N₂O. Compared with the T treatment, the accumulative amount of CO₂ under TS, NT, and NTS treatments were reduced by 5.95%(P=0.132), 12.94%(P=0.007), and 13.91%(P=0.004), respectively, and the accumulative amount of N₂O were significantly reduced by 31.23%(P=0.000), 61.29%(P=0.000), and 33.08%(P=0.000), respectively. Our findings suggest that conservation tillage significantly reduced CO₂ and N₂O emission from soil in the following winter wheat-growing season.