Study on variability of soil available nutrients in Shanxi province

Two villages were selected as experimental sites under different croping systems in Shanxi province. Soil samples were collected with grid method, and determined with soil nutrient systematic approach. Soil variability was studied with traditional statistics method and semi-variance function. The results showed that there existed spatial variability of soil nutrient under different plantation system. N, P and OM had a greater variability, which were mainly affected by agricultural fertilization measures. On the contrary, Ca, Mg, K, Cu, Fe and Mn have a smaller spatial variability; Soil nutrient had semi-variance structure, and model best fit included spherical, linear and exponential. Semi-variance model were not always consistent for one nutrient, and though some nutrient had same model, there still existed different in the limit distance of spatial correlation and the extent of soil spatial variability. There existed stronger spatial correlation in Ca, N and Mn and K, P, and S had medium spatial correlation.