中文摘要：

以科尔沁沙地典型玉米农田为研究对象,采用动态密闭气室法（Li-6400,USA）测定分析了土壤呼吸速率日动态和季节动态变化及其影响因素。结果表明：（1）土壤呼吸速率日动态在晴朗天气条件下表现为平缓的单峰曲线,最大值和最小值分别出现在14：00-18：00和2：00-6：00;季节动态最高值出现在雨热同期的夏季,日平均值达到7.490μmolCO2·m-2·s-1。（2）指数模型能较好的描述温度对于土壤呼吸日动态和季节动态的影响。（3）土壤呼吸速率与近地表气温的相关性最强,对15cm土壤温度的变化最敏感。（4）生物因子对土壤呼吸的季节变化起着重要作用,根系生物量与土壤呼吸速率呈三次关系（R2=0.880,P〈0.05）。

英文摘要：

To explore the characteristics of soil respiration and its influencing factors at maize fields of Horqin Sandy Land,the daily and seasonal variations of soil respiration rate and environmental factors were measured with an CO 2 analyzer（ Li6400,USA） following the dynamic closed chamber method. Results showed that：（ 1） The daily variations of soil respiration rate followed single peak trend at sunny day; maximum and minimum values occurred in the period of 14： 00 - 18： 00 and 2： 00 - 6： 00,respectively. The seasonal peak of soil respiration rate reached 7. 490μmolCO 2 ·m2·s1in the summer.（ 2） For both daily and seasonal variations,the exponential equation fitted the relationship very well between the soil respiration rate and soil temperature.（ 3） There were most significant correlations between seasonal variations of soil respiration rate and the surface air temperature. The soil respiration rate was most sensitive to soil temperature at 15 cm depth.（ 4） Biofactor played an important role in seasonal variation of soil respiration rate; root biomass showed a significant cubic correlation（ R2= 0. 880,P 0. 05） with soil respiration rate.