Spatial interpolation model comparison and spatial differentiation analysis of farmland soil organic matter based on GIS—A case study at Leyuan town, Wangmo county, Guizhou province

Taking advantage of organic topsoil data of Leyuan town in Wangmo county, we can explore the spatial variability of tillage-layers oil organic matter content, and guide the evaluation and management of soil fertility, so as to achieve the sustainable use of land resource. Based on the status of land use maps, soil maps, evaluation of farmland database of Wangmo，this paper applied Kriging method of ArcGIS10.0 to analyze the spatial differentiation of cultivated soil organic matter of Leyuan town in Wangmo county, and elected the optimal Kriging interpolation model. The optimal Kriging interpolation model of tillage -layer soil organic matter on Leyuan town in Wangmo county was the Rational Quadratic model. When the search direction was 8 sectors, search points was 2-12, model interpolation was better, and R2 was 0.926. The value of C0/sill was 0.76, this showed that the spatial correlation of tillage-layer soil organic matter was very weak and was affected by human activities，like tillage，the application of fertilizers and cropping system.These factors made the spatial correlation of tillage-layer soil organic matter weaken, and gradually became homogenization.The range of variation of topsoil organic matter content was wide, but less affected by outliers, and the various data were provided with highly spatial correlation. At the same time, the Kriging interpolation distribution forecast figure could move forward a single step to conduct fertilizer.