免耕对华北平原潮土N2O和CO2排放的影响

    Effects of Non-Tillage on N2O and CO2 Emissions From Sandy Loam Soil in the North China Plian

    • 摘要: 采用静态—气相色谱法研究了免耕和常规耕作下玉米生长季华北平原潮土N2O和CO2的排放特征。结果表明,免耕土壤N2O累计排放量(以N2O-N计,下同)为0.31 kg·hm-2,略高于常规耕作土壤的0.27 kg·hm-2,两者没有显著差异。灌水、强烈降水或连续阴天会诱发土壤大量排放N2O,免耕处理N2O排放峰值(28.1~38.4 μg·m-2·h-1)高于常规耕作处理(18.6~25.7μg·m-2·h-1)。免耕处理CO2累计排放量(以CO2-C计,下同)为1880 kg·hm-2,显著高于常规耕作土壤的1333 kg·hm-2。土壤N2O和CO2的排放通量与土壤温度呈显著指数相关,常规耕作处理下的相关程度更高。

       

      Abstract: To investigate effects of non-tillage on N2O and CO2 emmissions in the North China Plain,a field experiment was conducted to measure N2O and CO2 emiisions from soil under conventional tillage and soil that had just assumed non-till-age practice,using close chamber technique and gas chromatography during the maize growing season.Cumulative N2O emission from the non-tillage soil was 0.31 kg·hm-2,just slightly higher than from the tilled soil,being 0.27kg·hm-2.In contrast,non-tillage significantly increased soil CO2 emission by 41.6% compared to tillage(1333kg·hm-2).N2O emission peaks appeared after irrigation,heavy rainfall or consecutive cloudy days.N2O emission peaks in the non-tillage treatment ranged from 28.1 to 38.4 μg·m-2·h-1,which were greater than those in the tillage treament (18.6-25.7 μg·m-2·h-1).N2O and CO2 fluxes in the two tillage systems displayed a significant exponential relationship with soil temperature,and the seasonal variation of N2O and CO2 fluxes could be better explained by soil temperature in tilled soil than in non-tilled soil.

       

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