[Spatial Variability and Distribution Pattern of Soil Organic Matter in a Mollisol Watershed of China]

Spatial variability of soil organic matter and its distribution pattern are the hot issues of soil scientific research. Selecting Haigouhe watershed as the study area, this paper mainly focused on the spatial variability, distribution pattern and its impact factors of SOM in the surface soil by classical statistics, Geo-statistics and "3S" technology. The results showed that: compared with the other black soil areas, the SOM content in Haigouhe watershed was a little lower, there was a spatial autocorrelation, and a moderate variability. Random factors, such as human activities, cultivation measures and so on, had little impact on the spatial variation, while the structural factors had a dominant function, and there was a remarkable spatial anisotropy of SOM. The SOM content reduced gradually from east to west with the familiar changes of height, so the co-kriging interpolation, selecting elevation as the co-variate, was employed to improve the accuracy. The spatial variability of SOM and its distribution pattern in Haigouhe watershed were greatly affected by topography and land use but weakly influenced by traffic, villages and other social factors. The surrounding environment of the samples would increase the uncertainty of spatial variability and interpolation of SOM and it cannot be ignored in future studies. In summary, it was a significant scientific research to analyze the spatial variability, distribution pattern of SOM and its main impact factors in a mollisol hilly watershed of China.