ABSTRACT
Since its endorsement by the IUSS in 1998, the World Reference Base for Soil Resources has established itself as a comprehensive soil correlation system. The system has so far been translated into nine languages and is used and tested all over the world. This paper summarizes the main attributes of the WRB, outlines preliminary results of its field-testing, and reflects on the place of WRB in the future. Although originally designed for general-purpose soil correlation at world scale, WRB is increasingly used as a classification system. This paper discusses how WRB correlates with the USDA Soil Taxonomy and draws attention to some major differences between the WRB and Soil Taxonomy. The issue of strict ranking of taxa and the rationale behind ranking have been major points of debate; a ranking scenario is presented here, mainly to stimulate the discussion. In addition, WRB definitions of diagnostic horizons, properties, and materials are discussed with reference to modern soil information systems. It is hypothesized that the IUSS Working Group RB might explore the zone between its present area of application and a detailed horizon classification system as elaborated by Fitzpatrick and Aitkenhead (2000).
