中文摘要：

草地生态系统在全球碳循环和气候调节中起重要的作用，探讨封育草地地下有机碳储量的变化特征对探索草地碳循环具有积极意义．通过野外观测和室内分析，研究了宁夏典型草原不同封育年限草地0～40cm土壤有机碳、根系碳储量和地下碳储量的变化特征．结果表明，随封育年限增长，土壤有机质含量和地下碳储量呈现上升一下降一再上升的变化趋势，根系碳储量总体呈上升趋势．随着土壤深度增加，土壤有机质含量呈降低趋势，根系碳储量呈现先增加再下降的趋势，地下碳储量在垂直分布上的变化规律不尽相同．

英文摘要：

The grassland ecosystem plays an important role in global carbon cycle and climatic regulation. It has a positive significance to explore the changed characteristics of enclosed grassland organic carbon stor- age for explore grassland carbon cycle . The characteristic of soil carbon, root carbon content and the un- derground carbon storage of grassland 0--40 cm soil layer in different enclosing years were studied. The results indicated that the content of soil organic carbon and underground carbon storage showed the change trend of rising up and down and rising again. The root carbon content was on the rise on the whole. Along with the soil depth increased, Soil organic matter content showed a trend of lower, and the soil root carbon content increased first and then down, but the underground carbon storage were not the same as the verti- cal distribution.