Study on Spatial Variability of Topsoil Nutrients in Kuqa County Based on GIS

Based on the analysis methods of GIS and geostatistics,spatial variability characteristics of topsoil(0—20cm)nutrient elements in Kuqa County were studied,the results showed that organic matter,total nitrogen,phosphorus and potassium are moderate degree of spatial variability and the coefficients of variation are 19.11%~65.34%.Theoretical models of organic matter and total nitrogen are fitful of spherical model,nitrogen,phosphorus and potassium fit the exponential model.Organic matter,total nitrogen,available nitrogen,phosphorus and potassium present a moderate degree of spatial autocorrelation due to combined effect of soil type,soil texture and fertilization.From the spatial distribution,the contents of organic matter,total nitrogen,available nitrogen and potassium showed significant flaky and patchy distribution in the southeast,decremented from southeast to the northwest,while phosphorus mainly presented plaques massive distribution,which was higher than the northeast to the southwest.In the study area,the contents of topsoil nutrients overall present the patterns that the southeast is higher than northwest direction.