Continuous soil nutrient data is the basic data of soil information system

soil nutrient spatial interpolation study becomes very important because it can affect the data reliability of soil nutrient data straightly. In this study

soil available kalium data

Zhouzhi county

Shaanxi province

is sampled and got the interpolation map of available kalium with OK

IDW

Spline and TSA according to interpolating sampling points. The cross validation results showed that OK is the best which used spherical model in these methods; although Spline and IDW could also produce fair and reasonable results

both of them were sensitive to sampling density

interpolation result appeared large prediction errors in those regions which had exiguous sampling points