Profile of the periglacial fragipan in loamy soils omnipresent in the Sonian forest
This horizon, called fragipan, has been formed in the periglacial period and is omnipresent and intact in the Sonian forest. In the surrounding landscape, agriculture has led to the disappearance of this feature. Polygonal structures are visible and allow roots to penetrate into deeper horizons where they can reach very fertile loess sediment, explaining the exceptional growth of tree species, especially beech. Author: Roger Langohr
