Documents

The fourth edition 2022 is the most recent World Reference Base. - WRB 2022 corrected 2024 (PDF) - WRB 2022 (PDF)

The work should be cited as:

IUSS Working Group WRB. 2022. World Reference Base for Soil Resources. International soil classification system for naming soils and creating legends for soil maps. 4th edition. International Union of Soil Sciences (IUSS), Vienna, Austria.

The lead author of the fourth edition is Peter Schad (Technical University of Munich, Germany). The fundamental decisions have been made by the members of the WRB Board: Lúcia Anjos (Brazil), Jaume Boixadera Llobet (Spain), Seppe Deckers (Belgium), Stefaan Dondeyne (Belgium), Einar Eberhardt (Germany), Maria Gerasimova (Russia), Ben Harms (Australia), Cezary Kabala (Poland), Stephan Mantel (The Netherlands), Erika Michéli (Hungary), Curtis Monger (USA), Rosa Poch Claret (Spain), Peter Schad (Germany), Karl Stahr (Germany), Cornie van Huyssteen (South Africa). Vincent Buness (Germany) and Margaretha Rau (Germany) served as secretaries of the WRB Board. The fourth edition comprises 13 Chapters:

1. Background and basics
2. The rules for naming soils and creating legends for soil maps
3. Diagnostic horizons, properties and materials
4. Key to the Reference Soil Groups with lists of principal and supplementary qualifiers
5. Definitions of qualifiers
6. Codes for the Reference Soil Groups, qualifiers and specifiers
7. References
8. Annex 1: Field Guide
9. Annex 2: Summary of analytical procedures for soil characterization
10. Annex 3: Horizon and layer designations
11. Annex 4: Soil description sheet
12. Annex 5: Guidance on database set-up
13. Annex 6: Colour symbols for RSG maps

Annex 1 and 3 replace the FAO Guidelines for Soil Description (2006).

The definitions in the WRB are based on field and laboratory data. The field data are according to Annex 1. The methods to obtain the laboratory data are listed in Annex 2 and described in the Procedures for Soil Analysis (Van Reeuwijk 2002). The latter are published by the International Soil Reference and Information Centre (ISRIC).

WRB Translations

• Catalan
• French
• Italian
• Korean
• Portuguese
• Serbo-Croatian
• Spanish

Soil Description Sheet

• Soil-description-sheet-24-02-29-General-and-Surface (PDF 144 KB)
• Soil-description-sheet-24-02-29-Layer-descriptions (PDF 383 KB)
• Ficha de descripción del suelo_24-11-08_general y superficie (PDF 119 KB)
• Ficha de descripción del suelo_24-11-08_capas (PDF 374 KB)

Guidance on Database Set-up

• WRB 4th-edition Soil-description-sheet v1.1xlsx (MS Excel)

Previous WRB editions

• WRB 2015

  The WRB Working Group has a strong relationship to the Food and Agriculture Organization of the United Nations (FAO), where the WRB documents are published.
  The third edition, update 2015, is available in eight languages:
  English
  French
  Spanish
  Russian
  Georgian
  Slovene
  Czech
  Polish

• WRB 2006

  PDF (1606 KB)

• WRB 1998

  PDF (440 KB)

  The definitions in the WRB are based on field and laboratory data. The field data are according to the FAO Guidelines for Soil Description (FAO 2006) and the laboratory data according to the Procedures for Soil Analysis (Van Reeuwijk 2002). The latter are published by the International Soil Reference and Information Centre (ISRIC).