Spatial coverage:25 Member States of the European Union where data available (Bulgaria and Romania are not included), Norway, Switzerland, Croatia, Albania.
File Type: Raster
Projection: ETRS89 Lambert Azimuthal Equal Area
Temporal coverage: 2009
The JRC created a quantitative map of estimated soil pH values across Europe from a compilation of 12,333 soil pH measurements from 11 different sources, and using a geo-statistical framework based on Regression-Kriging. Fifty-four (54) auxiliary variables in the form of raster maps at 5km resolution were used to explain the differences in the distribution of soil pHCaCl2 and the kriged map of the residuals from the regression model was added. The goodness of fit of the regression model was satisfactory (R2adj = 0.43) and its residuals follow a Gaussian distribution. The lowest values correspond to the soils developed on acid rock (granites, quartzite’s, sandstones, etc), while the higher values are related to the presence of calcareous sediments and basic rocks. The validation of the model shows that the model is quite accurate (R2adj = 0.56). This shows the validity of Regression-Kriging in the estimation of the distribution of soil properties when a large and adequately documented number of soil measurements are available.
The data are explained in a publication: "CONTINENTAL-SCALE DIGITAL SOIL MAPPING USING EUROPEAN SOIL PROFILE DATA: SOIL PH", Hannes Isaak Reuter, Luis Rodriguez Lado, Tomislav Hengl & Luca Montanarella, Hamburger Beiträge zur Physischen Geographie und Landschaftsökologie – 92 Heft 19/2008, pp. 91-102.