Spatial Variability of Total Nutrients in Arable Soil as affected by Different Sampling Distances

The spatial variability of total amount of N,P and organic matter in arable soil was studied at three sampling distances,i.e.100 meter,50 meter and 25 meter.The results indicated that the contents of total N and soil organic matter were low,and total the P content was medium.The coefficient of variation of total N changed in relatively small extent at dfferent sampling distance,but that of organic matter and total P was reduced with increasing sampling distance.The reasonable sampling numbers for soil organic matter,total N and total P were 24,34 and 10 respectively.The soil depth profile structure was the leading factor to influence the spatial variability of soil total nutrients,while the effect of random factor was weak.The influence of sampling distance on the spatial variability of soil total nutrients was not evident.The sampling distance of 100 meters could be appropriate to study the total nutrients of cultivated soil in arid areas precisely.