Effects Of Rest Grazing On Plant Diversity And Organic Carbon Storage On Stipa Baicalensis Steppe In Inner Mongolia

Rest-grazing had become one of the most important measures currently for ecological restoration and reconstruction of degraded grassland. The Stipa baicalencsis meadow Steppe in Hulunbuir were the research objects,the responses of plant diversity,soil ptysico-chemical properties, soil microbial diversity, soil enzyme activity and organic carbon storage to rest grazing were researched by field survey and laboratoty analysis.main results and conclusions from the research were summarized as follows:1. From the community biomasses, rest grazing could significantly increase the grassland productivity, as the rest grazing years increased, biomass of aboveground parts, litters, roots all increased.Different functional groups had different contributions to the community aboveground biomass.Perennial bunch grasses,perennial rhizomatous grasses and forbs all increase. Intermediate xerophytes increased as the rest grazing years prolonged.The biomass of dominant species Stipa baicalensis, Leymus chinensis increased, while the biomass of inferior grass Artemisia frigida and Thalictrum aquilegifolium reduced.2.Rest grazing made the soil organic matter, total nitrogen,total phosphorus, and available nitrogen, available phosphorus content increase; Soil enzyme activity increased with soil nutrient increase to some extent. Soil alkaline phosphatase, urease and catalase activity had a close relationship with soil nutrient and water content.3.Soil microbial biomass carbon,nitrogen (SMBC,SMBN)increased with the increase of rest grazing years. Rest grazing was more beneficial for improving the functional diversity of soil microbial community than free grazing. The carbon sources mostly used by soil microorganism were carbohydrates, amino acids, and lipid.4.From the perspective of carbon storage, rest grazing was good for the input of organic matter and the accumulation of organic carbon, as well as soil-vegetation system carbon storage, in the process of rest grazing, grassland system was a carbon sink. From the perspective of carbon sequestration cost, the total cost increased with the rest grazing years extended; The cost reduced with the extension of rest grazing years.