中文摘要：

探讨了不同围封年限（6、8、30年）对大针茅草原生产力和土壤碳氮贮量的变化，以期构建围封年限与草地利用的关系，为草地管理提供科学依据。本实验通过实地样方调查及实验室分析，对不同围封年限大针茅草原群落的植被、土壤特征进行测定，分析了不同围封年限草原的生物量、土壤有机碳、氮贮量的恢复情况。结果表明：与持续自由放牧样地相比，围封后草原的生物量和土壤碳、氮贮量均呈显著增加；随着围封年限的延长，生物量和土壤碳、氮贮量也表现出增加的趋势，地上生物碳和土壤有机碳的增加趋于稳定。

英文摘要：

In order to obtain relationship between grassland utilization and enclosure duration to provide a scientific basis for grassland management, this paper studied grassland productivity, soil organic carbon and total nitrogen storage. The vegetation and soil characteristics were determined, and the grassland biomass, soil organic carbon storage and total nitrogen storage were analyzed by field quadrat surveys and laboratory analysis. The results show that grassland biomass, soil carbon storage and total nitrogen storage were significantly increased after grazing exclusion compared with the continuous grazing grassland. With the extension of enclosure, the biomass, soil carbon storage and total nitrogen storage also showed an increasing trend, and the increments of biomass carbon and soil organic carbon gradually kept stable.