A WRB-based buried paleosol classification

Abstract

Present classification systems for buried paleosols are inadequately developed. Several classification systems for paleosols, based on the US Soil Taxonomy, have been developed recently, but their use is still very limited. We propose appilcation of the World Reference Base for Soil Resources, which uses only substantial profile characteristics, as a background for the development of a new buried paleosol classification. The system was adapted for the use for buried paleosols. Dynamic criteria, which could be altered by diagenesis, were disregarded, and the definitions of most horizons were modified. A new prefix “infra-” was applied for modified diagnostic horizons and properties, and for refernce groups of buried paleosols. As a result, 11 diagnostic horizons, 2 properties and 2 materials were left with their definitions and names; 9 diagnostic horizons and 2 properties were modified, and named with the prefix “infra”; 14 diagnostic horizons, 6 properties and 4 materials were excluded or joined with others; and two new diagnostic horizons were proposed. This relationship reflects the balance between stable and dynamic properties in the diagnostic criteria used by the WRB. The number of soil units proposed for buried paleosols is fewer, than for surface soils in the WRB (25 instead of 30). The use of WRB modifiers, reflecting dynamic soil properties, was tentatively recommended for the second-level buried paleosols classification with prefixes “pedo-” for pedogenically derived properties, and “dia-” for the properties caused by post-burial processes. The application of the proposed system to a set of paleosols, previously described in the literature, showed its utility for buried paleosol classification.