Abstract: 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.

Key words: root branch order, Castanopsis platyacantha, root chemistry, nitrogen deposition, root morphology