中文摘要：

为了研究水分非均匀分布条件下旱地土壤CO2的排放特征,采用静态箱-气相色谱法测定了SI、SDI12、SDI15及SDI18共4个处理的CO2排放通量。结果表明：总体上CO2排放通量平均值表现为SI〉SDI12〉SDI15〉SDI18,但仅SI处理与SDI18之间的差异具有显著性;2次灌水后SDI处理土壤CO2排放较高的WFPS范围分别是25.9%~33.8%和31.5%~33.0%,低于SI处理出现高峰排放的WFPS分别为47%和34.1%;由于温度的影响第2次灌水后CO2排放通量总体上高于第1次灌水后,但第1次灌水后CO2排放通量与温度具有较强的相关性,而第2次灌水后两者之间相关关系不显著,可能存在过高温度下的土壤呼吸抑制。此外降雨发生时空气湿度的增加对微生物的呼吸有刺激作用,各处理降雨后出现了短期的CO2排放通量的小高峰。

英文摘要：

To reveal the carbon dioxide emission from soil with different moisture profile,the static opaque chamber-gas chromatograph method is used to measure CO2 fluxes of SI,SDI12,SDI15 and SDI18treatments.Generally,the average of CO2 emission fluxes from different treatment are in the following sequence：SI〉SDI12〉SDI15〉SDI18,but there are no significant difference between the treatments except between SI and SDI18 treatments.The WFPS range in which CO2 emission flux is high are 25.9%-33.8%WFPS and 31.5%-33.0% WFPSin SDI treatments after the first and second irrigation,which are lower than that in SI treatments（47% WFPSand 34.1% WFPS）.High temperature during the period after the second irrigation results in high CO2 emission fluxes,compared with that after the first irrigation.The CO2 emission fluxes are significantly related to the soil temperature after the first irrigation,but not after the second irrigation.The soil respiration might be depressed at high temperatures.Additionally,the increased air humidity after rainfall likely stimulated the soil microbial respiration,sub-peaks of CO2 emission are observed after the rain.