土壤呼吸速率是反映陆地生态系统功能的重要指标之一。采用土壤碳通量测量系统LI-8100A 对甘肃省玉门镇饮马农场5种不同植被类型土壤(裸地、葵花、小麦、孜然、茴香)呼吸速率、空气湿度、土壤温度、水分等影响因素的日动态变化规律进行了监测，分析了不同植被类型土壤呼吸速率的日变化特征及与环境因素的相关关系。结果表明，不同植被类型土壤呼吸速率明显不同，5种植被类型土壤呼吸速率的日平均值大小顺序为:茴香[7.710±1.705 μmol/(m2·s) ]＞ 小麦[5.266±0.953 μmol/(m2·s)] ＞ 葵花[5.237±0.568 μmol/(m2·s) ]＞ 孜然[3.504±0.431 μmol/(m2·s)] ＞ 荒地[2.567±0.666 μmol/(m2·s)] 。对于有植被覆盖的地块，土壤呼吸速率的日变化呈现先减小，后逐渐增大，在13:00 — 15:00时达到峰值，随后逐渐减小的趋势，大致呈“S”型曲线；而对于裸地，土壤呼吸速率的日变化呈现先增大后逐渐减小的趋势，大致呈“M”型或倒“V”型。

The soil respiration rate is one of the important indices for terrestrial ecosystem. This paper studied the dynamic variation of soil respiration rate, air relative humidity, soil temperature and soil moisture under different vegetation condition (wasteland, sunflower, wheat, cumin, aniseed) by soil carbon flux measurement system (LI-8100A) in Yinma farm of Yumen County of Gansu province in July 2012, and the correlation between the change of the soil respiration rate and the environment factors. The result indicated that there were significant differences in soil respiration among the various vegetation types, and the soil respiration rate of different vegetation were in the sequence of aniseed(7.710±1.705 μmol/m2·s) ＞ wheat(5.266±0.953 μmol/m2·s ＞ sunflower(5.237±0.568 μmol/m2·s) ＞ cumin(3.504±0.431 μmol/m2·s)＞wasteland(2.567±0.666 μmol/m2·s). The diurnal variation of soil respiration rate under vegetation cover presented a decrease with time, and then increased, and the maximum value of soil respiration rate appeared at 13:00 — 15:00 pm, and then decreased. The daily variation of soil respiration rate can be described approximately as curve of “S”; The diurnal variation of soil respiration rate under uncovered land presented a increase with time, and then decreased, the daily variation of soil respiration rate can be described approximately as curve of “M” or an inverted“V”.

S154.1

国家自然科学基金项目(41163002，41363004)共同资助。