Human-influenced soils from an iron and steel works in Naples, Italy

The study of soils formed by human activities is one of the concerns of modern pedology. In Italy, data on highly human-disturbed soils are not available. We investigated the soils from a recently dismantled iron and steel production plant, and compared them with natural soils in undisturbed adjacent areas. The industrial activity in question started 80 yr ago. The dominant morphology of the disturbed soils results from the stratification of materials used in and derived from the industrial process, which were variously mixed with earthy materials. Layers with variable thickness occur up to the 2-m depth. The spoil layer sequence is rarely interrupted by an applied natural soil, or in situ formed horizons, indicating the continuity of material deposition. Natural subsurface primary horizons are either obliterated or highly disturbed. We also recognized highly disturbed soils without significant spoil materials. All soils show high variability in their characteristics. They also have morphological and chemical features, such as horizonation, pH, organic C and total N content, distinctly different from those of natural soils. Problems emerged in classifying the investigated soils consistently with the current requirements of the U.S. soil taxonomy. To overcome such difficulty, we propose the adoption of the foundric subgroup of the Xerorthents. Such soils may be of interest in the discussion of the International Committee on Anthropogenic Soils (ICOMANTH), which is charged with studying and defining criteria for an appropriate taxonomic classification of highly human-influenced soils.