Saturday, 15 July 2006

National Classification of forest soils and their correlation with the WRB.

Tamas Szegi, Pal Stefanovits, and Erika Micheli. Szent Istvan University, Soil Science and Agrochemistry Department, Pater K. u. 1., Godollo, 2103, Hungary

This poster is one of a series discussing the classification and correlation problems of soils of Hungary.

The brown forest soils main type belongs to “zonal” soils in the Hungarian Soil Classification System (HSCS). These soils are separated from others based on the presumed ancient forest vegetation and the apparent soil formation processes like leaching, clay migration, acidification, podzolisation, or reduction features. On the lower level of the classification different types and subtypes are distinguished according to the presence and strength or dominance of these processes, however in most cases there is a lack of adequate definitions. The variety and the number of types is very wide, from moderately developed “brown earth” (characterized by leaching and structure and colour development) through the well developed “lessivated brown forest soils” (with clay redistribution), the “pseudogleyic brown forest soils” (with reduction features caused by “perched” water above a slowly permeable clay accumulation horizon) and the “podzolic brown forest soils” (with podzolization) to the transitional subtypes like “csernozjom brown forest soils”. In the World Reference Base for Soil Resources (WRB) the “brown forest soils” may belong to different Reference Groups, such as Cambisols, Luvisols, Podzols, Planosols, Arenosols and Alisols. These Reference Groups have different, well-defined criteria of colour, organic carbon content, base saturation, clay illuviation, stagnic color patterns, etc. The “brown earth” in most of the cases key out as Cambisols, the rest of the forest soils types have many options. At the lower level of the WRB there are board, well defined choices (qualifiers) for further characterisation of the chemistry, colour and other features of the Reference Groups.

The poster will give examples (with pictures and data) for the Hungarian forest soils units and will discuss their classification and correlation problems with the WRB.

Suggestions will be provided for the improvement of the classification of Hungarian forest soils, including changes and/or introduction of definitions and limits of horizons, properties and materials and the newly constructed key for forest soils. Suggestions for improvement of some Reference Groups and qualifiers in the WRB will also be presented to improve characterization of these soils.

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