Pedogenetic Trends in Soils Formed in Technogenic Parent Materials

Abstract: Soils formed in technogenic parent materials are proliferating, and their pedogenesis remains inadequately understood. On investigation of soils formed in various technogenic materials reported in the literature and of a Technosol developing on iron industry deposits, potential specificities of pedogenesis within technogenic materials are discussed. Analyses have shown that pedogenetic processes observed in these soils are similar to those occurring in natural soils. However, some particularities have been highlighted, such as the coexistence of processes rarely encountered simultaneously in natural environments or high rates of soil development during the first stages of weathering. Technogenic materials display highly diverse constituents, wide spatial variability, and temporal discontinuities as a result of human activities. These inherent features, in interaction with other soil-forming factors, may govern pedogenesis by generating the following conditions: (i) a high diversity of pedogenetic processes, including processes occurring usually in dissimilar climatic regions; (ii) localized processes and distinct rates and orientations of soil development over short distance; and (iii) a succession and/or a superimposition of processes, constrained by the deposition of materials and human operations. This creates the potential for the simultaneity of processes coexisting rarely in natural soils developing in the same climatic region. These soils are likely to have a polycyclic evolution and to evolve toward groups of soils other than Technosols, depending on the dominant processes. Further investigations of the processes and their potential interactions occurring in a larger range of soils formed in technogenic materials are required to better predict the evolution of these soils