Aim of this work was to test the 2010 version of the WRB soil classification for compilating a map
of the soil systems of Italy at 1:500,000 scale. The source of data was the national geodatabase
storing information on 1,414 Soil Typological Units (STUs). Though, basically, we followed WRB
criteria to prioritize soil qualifiers, however, it was necessary to work out an original methodology in
the map legend representation to reproduce the high variability inside each delineation meanwhile
avoiding any loss of information. Each map unit may represent a combination of three codominant
STUs at the most. Dominant STUs were assessed summing up the occurrence of STUs
in the Land Components (LCs) of every soil system, where each LC is a specific combination of
morphology, lithology and land cover. STUs were classified according to the WRB soil
classification system, at the third level, that is, reference soil group and first two qualifiers, when
possible. Since the large number of delineations, map units grouping was needed to make the map
more legible. Legend colours were organized according to soil regions groups firstly, then by
considering the highest level of soil classification, so resulting a nidificated legend. The map
showed 3,357 polygons and 704 map units. The most common STU were Calcaric Cambisols, by
far followed by Calcaric Regosols, Eutric Cambisols, Haplic Calcisols, Vertic Cambisols, Cutanic
Luvisols, Leptic Pheozems, Chromic Luvisols, Dystric Cambisols, Fluvic Cambisols, and others
STUs belonging to almost all the WRB soil references. Keywords: geodatabase, soil system
