Abstract: The grassland soil carbon pool is rich in organic carbon storage and plays an important role in the global carbon cycle. Soil organic carbon (SOC), as the main storage form of carbon in the soil, is essential for regulating global climate. Grazing, as the most common grassland utilization pattern, affects the SOC content of grassland. However, the results of related research are inconsistent. The literature on the effects of grazing on SOC content in grasslands in China were comprehensively searched and the meta-analysis was used to carry out quantitative evaluation. The results showed that grazing significantly reduced SOC content by 20.78%. Under moderate and heavy grazing conditions, the SOC content of grassland decreased significantly by 14.62% and 45.5%, respectively, while light grazing had no significant effect on SOC content. Climatic factors (precipitation and temperature), environmental factors (elevation and soil depth), and management practices (grazing duration) affected the responses of grassland SOC content to grazing to varying degrees, respectively. This study quantitatively analyzed the effect of grazing on the SOC content of grasslands in China and provided scientific basis and theoretical references for grassland grazing management and responses to climate change.

Key words: Grazing, Soil organic carbon, Grassland, Meta-analysis, China

摘要： 草地土壤碳库贮存着丰富的有机碳储量，在全球碳循环中占有重要地位，土壤有机碳(Soil organic carbon,SOC)作为碳在土壤中的主要储存形式，对调节全球气候至关重要。放牧作为最广泛的草地利用方式影响着草地SOC含量，然而有关研究结果不尽相同。本研究全面检索了放牧对我国草地SOC含量影响的文献，利用Meta分析开展定量评估。结果表明，放牧使我国草地SOC含量显著降低20.78%。在中度和重度放牧条件下，草地SOC含量分别显著降低14.62%，45.5%，轻度放牧无显著影响。气候因素(降水、气温)、环境因素(海拔、土壤深度)和管理方式(放牧持续时间)分别不同程度地影响草地SOC含量对放牧的响应。本研究通过定量分析放牧对我国草地SOC含量的影响，为我国草地放牧管理、应对气候变化提供科学依据和理论参考。

关键词: 放牧, 土壤有机碳, 草地, Meta分析, 中国