Research on the Characteristics of Spatial Variability of Soil Nutrients in Farmland

We take a farmland as study region whose area is 256.2 hm2,lying in Sanqishi Town in Ningbo City,Zhejiang Province.By the method of geostatistics combined with GIS,we studied the characteristics of spatial variability of soil nutrients in the farmland.The results showed that the ratios of nugget and sill of available kalium,OM and pH are lower than twenty-five percent,which shows their strong spatial correlations;while that of available phosphorus and available nitrogen range from 25% to 75%,which shows medium spatial correlation.By using Kriging interpolation and according to the nutrients' criterion,we may master the levels and spatial variability of nutrients of soil.In general,the contents of available nitrogen,available phosphorus and OM are rich in the studied region,while available kalium is at moderate and low level.The spatial variability of pH and OM are not obvious.