This research was conducted in Huanghuadianzi watershed in Aohan Chifeng, Inner Mongolia. The influence factors of soil organic carbon density were mainly divided into human factors and natural factors; altitude, slop, normalized differential vegetation index (NDVI) and the shortest distance from path or the village (DIST) were selected as the influence factors. Based on field data samples of the study area, both remote sensing and geographic information system were applied. A geographically weighted regression model was used to study the spatial variations of soil organic carbon density and the different environmental factors. The results showed that the soil organic carbon density changed in the study area from 1.91 to 16.63 kg/m², with an average density 7.42 kg/m². The influence degrees of soil organic carbon density in different driving factors ranked as altitude >slop >NDVI >DIST. The influence of each factor on the soil organic carbon changed with spatial difference. Altitude and slope respectively showed a positive and negative correlation with soil organic carbon density. In general soil organic carbon density decreased with the increasing of altitude and slope in most of the study area and the correlation coefficients were -0.436 and -0.223, while positive effect were only in a few areas. On the other hand, the NDVI and DIST showed a positive correlation with soil organic carbon density, with the correlation coefficients of NDVI being from 1.37 to 1.45 and DIST being from 0.15 to 0.47. In order to analyze the spatial variation of each influence factor, a map of the regression coefficient distribution of the environmental factors and soil organic carbon density in the study area was provided, which provided a scientific basis for the efficient utilization of soil and the development of precision agriculture according to the local conditions.

soil organic carbon content  /  environmental factors  /  geographically weighted regression model  /  samll watershed  /  spatial variation