Spatial Variability of Soil Nutrient in Chongming of Shanghai, China by Using GIS and Kriging Method

The spatial distributions and variability of the main nutrients in the topsoil of Chongming island of China are explored by using geostatistics combining with GIS. The multi-scale model is used to analyze the spatial pattern of soil nutrient factors based on the principle of Minimum Nugget Effect to ensure the stability of the interpolation model with the high interpolating accuracy. The result shows that AK and CEC distributed with a moderate variance while AN, TN, AP and OM with strong variance. CEC has an insignificant autocorrelation, contrasting to the significant autocorrelation of TN. Multi-scaled model can harmonize the dilemma of global generalization and local accuracy; the maps of soil nutrients can illustrate the distribution of them in the continuity of the soil surface. The coefficients of soil fertility calculated based on the spatial analysis indicate that the anisotropism of these factors were affected by the soil salinity to different extent.