The Soil Organic Carbon Storage And Spatial Distribution Characteristic Study Under Small Watershed Of Gao Miao Tun

Soil organic carbon plays an impotant role in mitigating climate change and improving soil quality. In this paper, we had estimated the soil organic carbon under small watershed of Gao Miao Tun in Yanqing and studied their spatial distribution. Considering the land use type and topography factors simultaneously,we had taken 126 sample plots in studying area, including 101 sample plots having 0～ 20cm and 20～40cm layers and 25 sample plots only having 0～20cm layer. We obtained one sample from every layer of every sample plot, totally 223 samples. The result of the analysed samples showed that (1) the mean soil organic carbon content under the small watershed had moderate intensity variation. The difference of the mean soil organic carbon content under two different layers was significant (p< 0.05) and that will decrease with the depth increase. The optimal models of the soil organic carbon in two soil layers were exponential and the soil organic carbon in two soil layers had a strong spatial correlation; The soil organic carbon under two soil layers presented the basic consistency parcel areaparcel area. (2) Texture had significant effect on soil organic carbon content.In 0～20cm layer, SOC was significantly(P<0.01) negative correlation with clay content while a negative and positive correlation in 20～40cm layer between SOC and sand and silt content correspondingly. Among the topography factors, the influence of slope on soil organic carbon content was the most, the next was elevation,aspect.There were very significant correlation (p<0.01) between the soil organic carbon content and their corresponding water content. The mean soil organic carbon content of woodland in two layers was the most among all the land use types. In 0～20cm layer, the soil organic carbon content of woodland was significantly different(P<0.05) from that of cultivated land,grassland and garden while only prensents significantly different(P<0.05) with that in garden in 20～40cm layer. (3) The soil organic carbon density in woodland was more than that in any other land use types, so suggesting increasing woodland area when the relevant department of yanqing county carried out land planning and regulation to moderating the carbon dioxide in the atmosphere and mitigate the greenhouse effect.