Spatial Distribution Of Soil Carbon Density And Estimation Of Carbon Storage In The Grassland Of East Alxa Plateau

Soil carbon pool plays an important role in global climate change and material cycle. Soil carbon pool contains organic carbon and inorganic carbon pool, the change of soil carbon pool is closely related to the concentration of CO2in the atmosphere. Study on drought area carbon pool plays plays a unique role in in the global carbon cycle, so the research on the components and reserve of soil carbon pool in arid area will help us deepen our understanding of terrestrial ecosystem carbon cycle, providing theoretical basis for scientific management of soil carbon pool in the arid zone. East Alxa plateau is a typical arid ecosystems, which locate in the region of semi arid region translating to arid region. This paper studied the spatial variability and distribution of soil organic carbon and inorganic carbon density in the East Alxa plateau grassland, and the distribution in the profile of soil organic and inorganic carbon content and density under different vegetation types and soil types, estimating the soil carbon pool at the same time. The main conclusions are as follow:1. Soil organic carbon density has a strong spatial correlation, it decreased gradually to the northwest and southwest from Helan Mountain in the horizontal direction. The mean of soil organic carbon density of0-100cm soil layer is6.28kg/m2, organic carbon density less than2.0kg/m2account for78.92%of the study area.2. Soil inorganic carbon density has a moderate spatial correlation, the high value of soil organic carbon density presents in the south, and the low value in the north. The mean of soil inorganic carbon density of0-100cm soil layer is7.54kg/m2, area with inorganic carbon density range from4.0-8.0kg/m2accounted for76.94%of the study area.3. Vegetation and soil types have significant effects on soil organic carbon content and density as well as soil inorganic carbon content and density. In the layer of0-100cm, mountain meadow (subalpine meadow soil) has the highest soil organic carbon density, warm desert(grey-brown desert soil) has the least; Warm desert grassland has the highest soil inorganic carbon density, mountain meadow (subalpine meadow soil) has the least. Soil organic carbon content and density of mountain meadow, warm steppe and warm desert grassland decrease with the depth of soil; soil inorganic carbon content and density of warm steppe and warm desert grassland increase with the depth of soil profile. 4. The result of valuation of grassland carbon storage in the study area shows that:the estimation of soil organic carbon pool are9.53×1010kg,15.2×1010kg and8.42×1010kg respectively, basing on vegetation type、soil type and Kriging interpolation method, soil inorganic carbon storage are4.46×1011kg,4.64×1011kg and3.45×1011kg; total soil carbon storage were5.41×1011kg,6.16x1011kg and4.29×1011kg. Basing on the three methods above, average soil carbon storage of the study area is5.29×1011kg. The organic carbon storage is1.11×1011kg, inorganic carbon storage is4.18×1011kg, inorganic carbon storage was3.77times of organic carbon storage.