World Reference Base for soil resources

The idea of creating an international reference base (World Reference Base) for describing soils was launched, in the early 80's, jointly by the Food and Agriculture Organization (FAO) and UNESCO.

The first WRB issue was presented at the XVI^th International Union of Soil Sciences's World Congress, in Montpellier in 1998. The second one was released in 2006, at the XVIII^th World Congress in Philadelphia (United States).

Several workgroups of the IUSS are taking part in this initiative, of which can be cited the World Reference Base group, specifically created in that purpose, and the Cryosols and SUITMA groups.

WRB key principles

• 32 Reference soil groups (RSG) are discriminated
• The RSG are defined through soil properties defined in terms of :
  • Diagnostic horizons
  • Properties
  • Materials

In order to help describing even more precisely the soils, two other bases have been created :

• Qualifiers, meant to underline specific characteristics
• Specifiers, helping to stress on the depth of occurrence, or to express the intensity of soil characteristics

See also

• The FAO reference text, (2007 version)
• The classification key of the WRB