中文摘要：

为评估草地的碳源/汇功能, 探索可持续发展的草地管理措施, 以内蒙古锡林郭勒典型草原为研究区域, 采用野外调查取样结合室内分析的方法, 分析了土壤有机碳（Soil Organic Carbon, SOC）和土壤微生物量碳（Soil Microbial Biomass Carbon, SMBC）的变化规律, 探讨了围栏封育29年（WF29）、围栏封育8年（WF8）、补播苜蓿（Medicago sativa）（RA）、补播羊草（Leymus chinensis）（RC）、以及轻度放牧（LG）、中度放牧（MG）和重度放牧（HG）共7种处理对SOC和SMBC分布的影响以及草地SOC和SMBC碳库储量的大小。结果表明, 从土壤剖面来看, SOC、SMBC含量在土壤表层较高, 为草地的主要碳库, 随着土壤深度的增加呈现降低的趋势。土壤根系层（0－30 cm）中, WF8、WF29、RA、RC、LG和MG的SOC和SMBC均高于HG, 其中WF8正效应较为明显, 有利于提高SMBC与SOC含量。SOC与SMBC呈显著正相关关系（P〈0.05）。可以通过SMBC的变化反映SOC的变化, 进而反映SOC碳库的变化。经估算, 锡林浩特市草地0－30 cm总的SOC和SMBC碳储量分别为788.86和9.48 Gg。其中, 围封8年的SOC和SMBC碳储量的值都为最高, 分别为661.76和6.76 Gg, 人工种草措施的值均为最低, 分别为0.61 Gg和5.73 t。SOC和SMBC含量对于土壤肥力和土壤品质变化有指示作用, 可作为草地碳汇的重要评估指标。

英文摘要：

In order to evaluate the carbon source/carbon sink function of grassland and explore the sustainable grassland management measures, the combined methods of field sampling and laboratory analysis were employed to analyze the variation of soil organic carbon （SOC） and soil microbial biomass carbon （SMBC） in Xilingol typical grassland in Inner Mongolia. The effects of different management and grazing measures on the distribution and carbon reserves of SOC and SMBC were discussed. The studied measures included fenced enclosure for 29 years （WF29）, fenced enclosure for 8 years （WF8）, filling-up Medicago sativa （RA）, filling-up Leymus chinensis （RC）, and three grazing measures . The surface soil layer was higher carbon pool because the SOC and SMBC in the soil profile decreased with soil depth increasing. The SOC and SMBC of WF8 and WF29 were higher than that of HG in root system soil layer （0-30 cm）. There were significantly positive effects of WF8 management on SMBC and SOC. There was significantly positive correlation （P〈0.05） between SOC and SMBC. The variations of SMBC not only reflect the changes of SOC, but aslo reflect the changes of soil organic carbon pool. The total SOC and SMBC carbon reserves were 788.84 Gg C and 9.47 Gg C in Xilinhot, respectively. The SOC and SMBC carbon reserves were highest under fenced enclosure for 8 years （661.76 Gg C, 6.76 Gg C）, and lowest under the artificial filling-up measures （0.61 Gg C, 5.73 t C）. SOC and SMBC were the indicators of soil fertility and soil quality and important evaluation index of grassland carbon sink.