Spatial Variability of Black Soil Nutrients in Hilly Land

Geostatistics combined with geographical information system(GIS) were applied to treatment and analyze the spatial variability of 180 samples of soil nutrients in topsoil in Fuye village of Heilongjiang Province.Soil nutrient data in this study included organic matter,available N,P and K.The results indicated that the semivariograms of organic matter were best described by the Gaussian model,available N,P and K were best described by exponential model.The spatial variability of available N,P and K were moderately dependent and affected by both structural and random factors.However,their spatial heterogeneity degree was different.The spatial correlation of organic matter was highly dependent therefore,changes in organic matter mainly affected by structural factors.AvailableN had the longest correlation range(4405 m),and organic matter had the shortest(234 m),whereas available P was 543 m and available K was 1128 m.Spatial variability of soil nutrients could be contributed to the unbalance fertilization in this area.Based on the p resent situation and spatial distribution characteristics of soil nutrients,the elements in nutrient management were N、K and P in the study village.The analysis was useful to inform strategic planning of using farmland,to guide fertilizer application and to control soil erosion land degradation of Blacksoil in in the locality.