Soils—A Hidden World: A Case Study of Soil Sequences on Carbonate Parent Materials in Slovenia

Of all natural or physical elements of a landscape, soils are the most hidden ones. Topography, waters and living world are well visible, obvious and considered as the most important and attractive landscape features. While soils beneath our feet on the other hand are hidden from our sight and furthermore are even considered boring. All soil properties, processes and links to other elements are too often neglected, do not get a proper attention and due to ignorance, are treated poorly. Soil sequence or catena is a concept that deals with these hidden interlinks and reveals new information about landscape and soils. The study area comprises the eastern foot slopes of the Polhograjsko hills, on the western edge of the Ljubljana basin. Both entities are the part of the Pre-Alpine region, which extends south of the Alps, across the entire country. The lower parts of the Polhograjsko hills slopes consist of the Carboniferous and Permian, hard, siliceous clay and sandstones. On top of this, thick layers of hard and compact Triassic limestone and dolomites represent the upper part of slopes and summits. Soil genesis in the foot of the Polhograjsko hills and its slopes show a modified soil sequence (pedosequences), already described by Stritar in 1991. He states this is the most important soil sequence in Slovenia because it appears in all-natural regions (high and low mountains and hills and especially in karstic areas). The developing stages of soil on hard carbonate rocks show considerable regularity in appearance (limestones and dolomites of different periods) throughout the regions of Slovenia. The variety of soil groups on limestones and dolomites is closely connected or conditioned by the specific geomorphology of these surfaces, which are modulated by irregularly distributed sinkholes, smaller valleys and precipitous, larger plateaus, terraces and undulating valleys. This variegated relief by itself would not be a cause for such sudden changes and variations in soil forms where it is not for the associated micro-relief of the rock. Due to the high micro-variation of geological and topographical features, a term mosaic soil spatial distribution is used.