中文摘要：

为了预测农田生态系统中CO2、N2O、CH4的排放对全球气候变暖的响应，及其温度对温室气体排放日变化的影响，利用CO2分析仪、静态箱-气象色谱法，对黄土高原旱区农田生态系统传统耕作（T）和保护性耕作（NTS）措施下春小麦成熟期CO2、N2O、CH4气体通量日变化进行原位观测。结果表明：2种耕作措施下农田土壤均表现为大气CO2、N2O的源和CH4的汇。CO2、N2O、CH4都有明显的日变化特征，传统耕作措施下CO2排放通量明显高于保护性耕作。CO2日排放通量最高峰出现在12：00，最低峰出现在2：00。N2O日排放最高峰出现在16：00，最低峰出现在0：00。保护性耕作措施能增加农田土壤N2O排放通量的排放。2种耕作措施下CH4吸收通量的最高峰均出现在14：00，保护性耕作措施下CH4吸收通量的最低峰出现在22：00，传统耕作措施则出现在2：00。采取保护性耕作措施能促进农田土壤对CH4通量的吸收。地表温度，5 cm地温与CO2排放通量都有极显著的正相关关系，且都与CO2通量呈指数函数关系。N2O与各个耕层的土壤温度都有极显著的正相关关系，且与N2O排放通量呈线性函数关系。2种耕作措施下，CO2通量与地表温度的相关系数最高，N2O与10 cm地温的相关系数最高。CH4与地表温度具有极显著的负相关关系。

英文摘要：

In order to predict the farmland ecological system, CO2, N2O and CH4 emissions on global warming response and the influence of temperature on the daily dynamics of greenhouse gas emission. Daily dynamics of CO2, N2O and CH4 flux from farmland ecosystem in spring wheat field at mature stage were measured by static chamber-gas chromatographic techniques under conventional tillage （T） and conservation tillage （NTS） in dry land of loess plateau. The results showed that：fields were sources of atmospheric CO2 and N2O and the sink of atmospheric CH4 under two tillage treatments. Daily dynamics of CO2, N2O and CH4 flux changed remarkably. CO2 emission flux under conventional tillage was obvious higher than that under conservation tillage, the maximal emission flux of CO2 appeared at 12：00 pm, and the minimum emission appeared at 0：00 am. The maximal emission flux of N2O appeared at 16：00 pm and the minimum emission appeared at 0：00 am. Conservation tillage treatment could increase N2O emission. The maximal absorption flux of CH4 appeared at＆nbsp;14：00 pm under two tillage treatments, the minimum absorption appeared at 22：00 pm under conservation tillage, but the minimum absorption appeared at 2：00 am under conventional tillage treatments. Conservation tillage could increase CH4 absorption. The land surface temperature and soil temperature at the depth of 5 cm were significantly related to CO2 emission flux, and that there was a significant exponential correlation between CO2 flux and the soil temperature.