Spatial variability of soil nutrients and pH in vegetable fieldin typical area of Taihu Lake watershed

In the present investigation,156 top layer soil samples (0-20 cm) were taken in a regular grid of 50 m by 50 m at 50 hm2 area of vegetable plot located at the east part of Taihui road in Dapu town,Yixing city.Characteristics of spatial variability of soil nutrients and pH were studied by using traditional statistics and geo-statistics.The results showed:there were obvious differences between eight soil nutrients in spatial variation-structure.Semivariograms for available soil P fitted linear model,NH+_4-N fitted linear model,others fitted exponential model.Spatial correlation in total nitrogen and pH lay in intensity.Total P,available P,NH+_4-N,available K,available N were moderate.There were obvious differences between eight soil nutrients in correlated distance.NH+_4-N had largest correlated distance of all,about 1 226 m.NH+_4-N spatial correlation was violent in relative large scale.While available P and available K had middle correlated distance,about 587 m and 498 m.The correlated distance of others was in the range of 84-201 m.