Effects Of Different Utilization And Grazing Intensity On Carbon Storage Of Vegetation-soil System In Typical Steppe

Environmental issues caused by human activities increasingly attract the attention of researchers underthe background of global change, and the structure change of carbon cycle has become a highlight inresearch. Grassland ecosystem, as the one of the main ecosystem of land, covered about1/4of landsurface. In the past decades, long-term human activities have had a profound impact on grasslandecosystem, especially on carbon sequestration. Under the great demand of promoting grasslandecological and productive function in China, developing research on “Effects of different utilization andgrazing intensity on carbon storage of vegetation-soil system in typical steppe” helps us to understandand master the degeneration mechanism of grassland ecosystem deeply, and provide theoretical basis forscientific conservation and rational utilization of grassland resources.Research took Xilingol typical steppe in Inner Mongolia as research area, selected representativevegetation types which were constructed by Stipa grandis and Leymus chinensis to research the carbondensity and distribution rule of vegetation-soil system under the different degradation grassland. Andanalysis the effects of different utilization way and grazing intensity on carbon sequestration ofvegetation-soil system, estimate the carbon storage and spatial pattern of vegetation-soil system oftypical steppe. The main results are as follows:1. The plant carbon content under the different utilization and grazing intensity was relativelystability, and the value was0.42-0.44, close to0.45, which was the internationalcommon-used conversion rate of carbon. Carbon density of above-and below-groundbiomass was decreased by the utilization intensity, and there was extreme significantcorrelation between them（P<0.01）.2.0-100cm soil organic carbon density of typical steppe under the different utilization andgrazing intensity was8.77-17.73kg/m2. The difference of carbon density under differentutilization and grazing intensity was greater than the spatial difference. Soil organic carbondensity was decreased by soil depth and logarithm regression equations can explain theregression relationship between the soil organic carbon and soil depth: no degradation:y=0.5685Ln(x)+3.118（R~2=0.849）, grazing lightly: y=0.6943Ln(x)+3.843（R~2=0.833）,grazing moderately: y=0.4932Ln(x)+3.26（5R~2=0.825）, grazing heavily: y=0.553Ln(x)+3.217（R~2=0.902）.3. Proper use of grassland was beneficial to the carbon sequestration. Of vegetation-soil systemand can be explained by plant hormone content, soil physical and chemical properties and soil microbial number and mass.4. The estimate value of vegetation-soil system carbon storage was1.51Pg, and96%of carbonwas stored in soil. Carbon estimate method adopted in this research which combinedvegetation method and model method was feasible.