Spatial variability of soil properties at hillslope level

The aim of this paper is to analyze the spatial structure of several soil properties at 0-30 cm soil depth: pH in water and in KCl, contents of organic matter, sand, silt and clay, at a 2.1 ha hillslope in northwest Spain. The semivariograms and correlations between these soil properties and several variables derived from DEM (Digital Elevation Model) data, such as slope and elevation, were calculated. A medium correlation was found between pH and elevation, and the results obtained using kriging with external drift were similar to those obtained with ordinary kriging. Estimations of sand, silt and clay contents were used to calculate texture maps using ordinary kriging and Gaussian conditional simulation. Small differences were observed between maps obtained with these two methods.