锡林河流域典型草原碳素生物小循环研究

应用生物地球化学分室方法研究了内蒙古锡林河流域2个典型草原群落——羊草草原和大针茅草原的碳素生物小循环,研究表明:①生长季禁牧的羊草草原植物分室碳素净固定量为165.50 gC.m-2,土壤分室碳素净排放量为174.36 gC.m-2,系统碳素净固定量为-8.86 gC.m-2,基本处于平衡状态,植物分室的碳输入和碳输出也近于平衡状态;②生长季禁牧的大针茅草原植物分室碳素固定量为130.04 gC.m-2,土壤分室碳素净排放量为128.28 gC.m-2,系统碳素净固定量为1.76 gC.m-2,基本处于平衡状态,植物分室的碳输入和碳输出在降水量大的年份以输入为主,在降水量小的年份近于平衡状态;③水热等生境条件较适宜的羊草草原碳素周转量比大针茅草原要大得多,水分是典型草原碳素循环量的主要影响因素。

A Study on Carbon Biogeochemical Cycles in Inner Mongolia Steppe, China

Carbon cycles of two steppes in Xilin River Basin were studied using biogeochemical cycle compartment theory. The major results include: 1) For the soil-palnt-atmosphere system of fenced Leymus chinensis steppe, the net carbon fixed by the plant compartment was 165.50 gC·m^-2 during the growing season, the net emission from soil compartment was 174.36 gC·m^-2,so the net carbon fixed by the system was -8.86 gC·m^-2. In general, the input and output of carbon were nearly equivalent. The plant compartment was approximately balanced, too. 2) For the soil-plant-atmosphere system of fenced Stipa grandis steppe, the plant compartment fixed 130.04 gC·m^-2 during the growing season, the net carbon emission from soil compartment was 128.28 gC·m^-2, therefore the net carbon fixed by the system was 1.76 gC·m^-2. The carbon input into plant compartment far exceeded the carbon output in wet year and it would become balanced in drought year. 3) The turnover of carbon element in Leymus chinensis steppe is larger than Stipa grandis steppe, which is caused by the more suitable geographical conditions. Water content is the main affecting factor of carbon cycles in Inner Mongolia steppe.