Mapping soil properties for Europe : spatial representation of soil database attributes

The European Soil Database (ESDB) of the European Commission Joint Research Centre provides the most detailed and comprehensive set of data for soil properties with pan-European coverage. However, using the ESDB soil properties in combination with spatial applications is hampered by the structure of the database for soil typological attributes. In this study a layer of mapped typological units was used to resolve issues related to the database structure for the spatial representation of soil properties and to map key soil properties to standardized spatial layers. The information available form the ESDB tends to be more suited to characterise the site of a soil unit, including morphological conditions. The range of soil property data was extended by the Harmonized World Soil Database (HWSD), which provides more detailed information on soil properties. Combining data from both databases was achieved by processing the attributes in a database management system and then linking the output to a spatial reference layer and by transferring attributes to the spatial layer from each database and processing the data by spatial overlay functions of a Geographic Information System (GIS). The information offered by the ESDB and the HWSD was combined with the spatial reference layer of typological units to derive other soil properties, which are not readily available from the databases. To provide a measure of the effect of using the information of all STUs instead of only the information given for the dominant STU the soil available water content was estimated using different processing options.