Proposal for a new diagnostic horizon for WRB Anthrosols

Abstract

To investigate man's role in the creation and evolution of soils in areas of large scale farming, and to investigate the main morpho-descriptive aspects of the related soils, a survey was carried out in south eastern Sicily, Italy, where, as common to other regions of the Mediterranean basin, there are wide areas with anthropogenic soils due to large scale farming activity. The complex genesis pattern of these anthropogenic soils, which shows a double sequence of man-made horizons, sideways oriented to the soil surface, does not allow their classification as Technosols, because their composition is not dominated or strongly influenced by artefacts or human-made materials as is the case for Technosols. According to the principles of the WRB (World Reference Base for Soil Resources), these soils should be regarded as being within the Anthrosols reference soil group (RSG). For their classification, the “geomiscic” horizon, not listed among the diagnostic horizons of the WRB, is proposed as a new diagnostic horizon for the Anthrosols RSG. The geomiscic horizon can be succinctly defined as “a horizon that develops when a layer, at least 30 cm thick of different kinds of earthy materials, is added to the soil using earthmoving equipment. For farming purposes this layer is subsequently deeply mixed into the underlying soil using heavy machinery. Its colour is related to the source materials and generally the layer is not parallel to the surface of the soil”