Spatial Variability of Soil Organic Matter and Some Available Nutrients in Shuangcheng,Heilongjiang Province

Geographical information system(GIS) combined with Geostatistics was applied to reveal the spatial variability of soil nutrients including organic matter,available N,available P and available K in the topsoil (0~20cm) in Shuangcheng Heilongjiang Province.The results showed that theoretical semivariogram models of organic matter,available N,available K were best described with a spherical model,whereas the available P was best fitted with an exponential model.The ratios of nugget to sill of available K was 49.96%,indicating that the spatial correlation was moderately spatially dependent and the spatial variability was affected by structural and random factors together,while organic matter,available N and available P were from 8.10% to 14.39%,indicating that the spatial correlation were all strongly spatially dependent,and the spatial variability was affected by structural factors.The findings indicate that the contents of four nutrients were enriched from west to east and from southwest to northeast.