Research on Soil Organic Carbon Spatial Distribution in Qilian Mountain Based on Geographic Information System and Spatial Analysis Technology

Geographic Information System and spatial analysis technology were used, soil organic carbon (SOC) spatial variation and distribution under different vegetation were studied the paper at west, middle and east sections of Qilian Mountain, in cold and humid region of northwest China, Gansu province. In August 2004, 44 surface soil samples (0-20cm) were collected covered with different vegetation in the upper reach of Shiyang River, Heihe River and Shule River, the three inland river basins in the Hexi corridor. The results show the following parts. (a) Mean SOC presents the trend of middle > east > west in Qilian Mountain. Under the control of SOC, soil properties including soil texture, TN, TP, TK and CEC are the same trend as SOC, but soil pH and CaCO3 are reverse. And it has close relationship between SOC and less than 50 mu m particle size. (b) SOC content is higher at middle and east sections under different vegetation than that at west. And in the process of vegetation and precipitation, SOC spatial distribution has obvious variation with longitude, latitude and altitude.