Application of geostatistical techniques in mapping topsoil and subsoil chemical composition

Geostatistical techniques are commonly used for converting field measurements into continuous surface.The objective of this study was to show the better use of them in the interpolations of the topsoil and subsoil variables in an agricultural catchment.This study was conducted in a watershed basin in Tokat, Turkey in 2011. As an example, the spatial variability of pH, and two important heavy metal concentrations, Fe and Cu were examined. The soil samples were taken and analyzed at two depths (0-30 and 30-60 cm). After checking normality, stationary and outliers, the ordinary kriging and isotropic cokriging methods were conducted to infer the spatial distribution of variables selected by using training data set that contains 115 sample points and test data set that contain 27 sample points.The proposed method (cokriging), in which two or more variables are used, were compared with the method (kriging) in which one variable is used. The results showed that the approach, had higher accuracy statistics than the conventional kriging mapping method.