Spatial Variability of Soil Organic Matter and Its Influencing Factors at County Scales

Study on the spatial variability of soil organic matter can provide useful information for promoting land productivity.In this investigation method of geostatistics combined with GIS was used to analyze the spatial variation characteristics of soil organic matter and its influencing factors in Shuangliu County of Sichuan Province,China.The results indicated that soil organic matter was 29.72 g/kg which was more than middle level,and its coefficient of variation was 30.11%.The spherical variogram model fitted the sample variograms very well,and it was highly spatial correlated,the spatially dependent range was 91.10 km,C0/(C0+C) was 12.67%.Through ordinary Kriging interpolation,the soil organic matter in the north was highest and was reducing towards the southeast.SSR test indicated that the soil organic matter was significantly different depending on soil types and terrain conditions.The land use and fertilization application rate strongly affected soil organic matter,and its increasing trend was attributed to straw manure.