【作者】 萨茹拉；

【导师】 侯向阳； 李金祥；

【作者基本信息】 中国农业科学院 ， 草业科学， 2013， 博士

【摘要】 全球变化背景下人类活动引起的环境问题越来越多的引起关注，碳循环格局的改变逐渐成为研究的热点。草地生态系统作为陆地最重要的生态系统之一，覆盖陆地表面1/4左右。过去几十年，长期人类活动对草地生态系统，尤其是碳蓄积产生了深刻的影响。在提升我国草原生态生产功能的重大需求下，开展“不同利用方式和放牧强度对典型草原植被-土壤系统碳储量的影响”研究，有助于我们深入地了解和掌握草地生态系统退化机理，为科学保护和合理利用草地资源提供理论依据。本研究以内蒙古锡林郭勒典型草原为研究区域，选择以大针茅（Stipa grandis）和羊草（Leymuschinensis）为建群种的代表植被类型，研究了不同退化草地植被-土壤碳密度及其分布规律，解析了不同利用方式和放牧强度对草地植被-土壤碳蓄积的影响，估算了典型草原区域植被-土壤碳储量并分析了其空间分布格局，主要结论如下：1.典型草原不同利用方式和放牧强度下植物碳含量较稳定，为0.42-0.44，接近于国际上通用的植物碳转换率0.45。地上、地下植物碳密度随利用强度的增强而减少，且两者之间有极显著相关性（P<0.01）。2.典型草原不同利用方式和放牧强度下0-100cm土壤有机碳密度为8.77-17.73kg/m2，不同利用方式和放牧强度对土壤有机碳密度的影响大于空间差异，垂直分布呈显著的递减规律，且可以用对数关系进行描述草地碳密度与土壤深度之间的回归关系，即不退化草地y=0.5685Ln(x)+3.118（R~2=0.849），轻度放牧退化y=0.6943Ln(x)+3.843（R~2=0.833），中度放牧退化y=0.4932Ln(x)+3.265（R~2=0.825），重度放牧退化y=0.553Ln(x)+3.217（R~2=0.902）。3.典型草原适度放牧利用有益于典型草原植被-土壤系统碳蓄积，植物激素水平、土壤主要理化性状、土壤微生物数量与质量等可辅助解释这一现象。4.内蒙古锡林郭勒典型草原植被-土壤系统碳储量估算值为1.51Pg，其中96%的碳储存在土壤当中，研究所采用的植被法与模型法相结合的区域碳储量估算方法具有可行性。更多还原

【Abstract】 Environmental issues caused by human activities increasingly attract the attention of researchers underthe background of global change, and the structure change of carbon cycle has become a highlight inresearch. Grassland ecosystem, as the one of the main ecosystem of land, covered about1/4of landsurface. In the past decades, long-term human activities have had a profound impact on grasslandecosystem, especially on carbon sequestration. Under the great demand of promoting grasslandecological and productive function in China, developing research on “Effects of different utilization andgrazing intensity on carbon storage of vegetation-soil system in typical steppe” helps us to understandand master the degeneration mechanism of grassland ecosystem deeply, and provide theoretical basis forscientific conservation and rational utilization of grassland resources.Research took Xilingol typical steppe in Inner Mongolia as research area, selected representativevegetation types which were constructed by Stipa grandis and Leymus chinensis to research the carbondensity and distribution rule of vegetation-soil system under the different degradation grassland. Andanalysis the effects of different utilization way and grazing intensity on carbon sequestration ofvegetation-soil system, estimate the carbon storage and spatial pattern of vegetation-soil system oftypical steppe. The main results are as follows:1. The plant carbon content under the different utilization and grazing intensity was relativelystability, and the value was0.42-0.44, close to0.45, which was the internationalcommon-used conversion rate of carbon. Carbon density of above-and below-groundbiomass was decreased by the utilization intensity, and there was extreme significantcorrelation between them（P<0.01）.2.0-100cm soil organic carbon density of typical steppe under the different utilization andgrazing intensity was8.77-17.73kg/m2. The difference of carbon density under differentutilization and grazing intensity was greater than the spatial difference. Soil organic carbondensity was decreased by soil depth and logarithm regression equations can explain theregression relationship between the soil organic carbon and soil depth: no degradation:y=0.5685Ln(x)+3.118（R~2=0.849）, grazing lightly: y=0.6943Ln(x)+3.843（R~2=0.833）,grazing moderately: y=0.4932Ln(x)+3.26（5R~2=0.825）, grazing heavily: y=0.553Ln(x)+3.217（R~2=0.902）.3. Proper use of grassland was beneficial to the carbon sequestration. Of vegetation-soil systemand can be explained by plant hormone content, soil physical and chemical properties and soil microbial number and mass.4. The estimate value of vegetation-soil system carbon storage was1.51Pg, and96%of carbonwas stored in soil. Carbon estimate method adopted in this research which combinedvegetation method and model method was feasible.更多还原