中文摘要：

采用Li-8150多通道土壤碳通量自动观测系统,于2009年6月—2010年6月对呼伦贝尔地区贝加尔针茅草甸草原土壤呼吸进行连续野外观测,分析该地区土壤CO2通量排放特征.结果表明： 生长季内贝加尔针茅草甸草原土壤呼吸日动态呈单峰曲线,最高值出现在13：00—15：00,最低值出现在5：00—6：00,土壤呼吸呈明显的季节变化,与土壤温度和土壤含水量季节动态相吻合.土壤呼吸与各层土壤温度和土壤含水量关系可以用线性模型和指数-乘幂模型来表示;土壤呼吸与各层土壤温度呈显著的指数回归关系，Q10变化范围分别为1.68～2.14和3.03～3.60,非生长季土壤温度对土壤呼吸的影响更为显著;生长季内土壤呼吸与10 cm土壤含水量呈显著正相关.2009和2010年土壤CO2年排放量分别为488.47和507.20 g C·m-2·a-1,生长季排放量约占年排放量的90%.

英文摘要：

Based on the measurement of soil CO2 evolution with the Li8150 from June 2009 to June 2010, the characteristics of soil CO2 flux from the Stipa baicalensis meadow steppe in the Hulunbeir, Inner Mongolia were analyzed. The daily dynamics of soil respiration rate in this study area presented a peak curve in growing season, the daily maximum value appeared in 13：00-15：00 p.m., while the minimum value appeared in 5：00-6：00 a.m. The soil respiration had obviously seasonal dynamics, similar with the dynamics of soil temperature and soil water content. The relationships of soil respiration with soil temperature and soil water content could be better expressed with linear or exponentialpower equation. Using the Van’t Hoff exponential equation to fit soil respiration and soil temperature, the results showed that they all had good exponential regression relationships in growing season and in non-growing season. Q10 was slightly different at different depths, varying from 1.68 to 2.14 in growing season and from 3.03 to 3.60 in non-growing season. The effect of soil temperature on soil respiration was more sensitive in non-growing season than in growing season. There was significant a correlation between soil respiration and soil water content at the depth of 10 cm. The annual soil CO2 fluxes were 488.47 g C·a-1 and 507.20 g C·a-1 in 2009 and 2010, respectively. The contribution of soil respiration in growing season to the annual soil CO2 flux was about 90%.