World Reference Base for Soil Resources

World Reference Base for Soil Resources
Name	World Reference Base for Soil Resources
Abbreviation	WRB
Established	1998
Governing body	International Union of Soil Sciences
Latest revision	2015
Type	International soil classification

World Reference Base for Soil Resources is an international framework for naming and classifying soils, developed to harmonize soil terminology among nations, research bodies, and land management agencies. It serves as a common reference for comparative soil science, facilitating communication among institutions such as the Food and Agriculture Organization, International Union of Soil Sciences, United Nations Educational, Scientific and Cultural Organization, International Soil Reference and Information Centre, and national agencies including United States Department of Agriculture and European Commission. The system links to global mapping initiatives, environmental assessments, and agronomic practices under programs led by World Bank, United Nations Environment Programme, and regional research networks like the European Soil Bureau Network.

Overview and history

The WRB originated from efforts at the International Union of Soil Sciences congresses during the late 20th century and was formally published following collaboration among scientists from institutions such as the International Soil Reference and Information Centre, Food and Agriculture Organization, and national services including the Bundesanstalt für Geowissenschaften und Rohstoffe and Australian Soil and Land Survey Field Handbook contributors. Early influences include national systems such as the United States Department of Agriculture soil taxonomy, the Russian soil classification (1977), the Brazilian Soil Classification System, and the German Soil Science Society nomenclature. Major milestones involved adoption at international meetings like the World Soil Congress and incorporation into global projects overseen by the World Bank and European Commission for soil monitoring. Revisions responded to inputs from research organizations such as the International Geosphere-Biosphere Programme and field practitioners from institutions like the Commonwealth Scientific and Industrial Research Organisation.

Classification system and diagnostic horizons

WRB uses diagnostic horizons, properties, and materials similar in role to those in the United States Department of Agriculture soil taxonomy and parallel to concepts in the Canadian System of Soil Classification and French soil classification. Diagnostic horizons in WRB (e.g., organic layers, cambic-like horizons, argic-like horizons) are defined to allow correspondence with criteria used by agencies such as the European Commission and research centers like the International Soil Reference and Information Centre. The system specifies diagnostic properties (e.g., clay increase, carbonate accumulation, gleyic features) that align with field protocols from organizations such as the Food and Agriculture Organization and national mapping programs run by bodies like the United States Geological Survey and Geological Survey of Canada. WRB rules for qualifiers, principal qualifiers, and reference soil groups enable translation between nomenclatures used by researchers at universities such as Wageningen University, University of California, Davis, and University of São Paulo.

Soil units and reference soil groups

The core of WRB consists of Reference Soil Groups (RSGs) that provide globally recognizable units akin to classes in the United States Department of Agriculture soil taxonomy or orders in the Canadian System of Soil Classification. Examples of RSGs correspond in practice to soils studied at sites associated with institutions like CERN (for site research logistics), experimental stations of the International Rice Research Institute, and observatories coordinated by the Global Soil Partnership. Each RSG may be modified by principal and supplementary qualifiers used by national services such as the Australian Soil Classification authority or the Servicio Nacional de Meteorología e Hidrología de Perú for local adaptation. The list of RSGs supports interoperability with thematic datasets used by organizations including the European Soil Data Centre and research consortia at Imperial College London and ETH Zurich.

Applications and global mapping

WRB is applied in global soil mapping initiatives led by the Food and Agriculture Organization, European Space Agency, and the Global Soil Partnership, and in projects funded by the World Bank and regional development banks such as the Asian Development Bank. It underpins land evaluation in programs run by the United Nations Environment Programme, climate change assessments coordinated with the Intergovernmental Panel on Climate Change, and biodiversity studies linked to the Convention on Biological Diversity. National soil information systems maintained by entities like the United States Department of Agriculture, Instituto Brasileiro de Geografia e Estatística, and British Geological Survey often provide WRB-based translations for international reporting. WRB classifications feed into digital soil mapping workflows using tools developed at Wageningen University, ETH Zurich, and the International Soil Reference and Information Centre.

Comparison with other classification systems

WRB is often compared with the United States Department of Agriculture soil taxonomy, the Canadian System of Soil Classification, the Chinese Soil Taxonomy, and national schemes such as the Australian Soil Classification and Russian soil classification (1977). Unlike the hierarchical structure of the USDA soil taxonomy orders and the categorical tiles of the Canadian System of Soil Classification, WRB emphasizes internationally transferable Reference Soil Groups and qualifiers, facilitating translation for multinational assessments by organizations such as the Food and Agriculture Organization and European Commission. Comparative studies from universities like Wageningen University, University of Hohenheim, and research institutes including the International Soil Reference and Information Centre have evaluated congruence among systems to support global databases used by the World Bank and Intergovernmental Panel on Climate Change.

Development, governance, and revisions

Governance of WRB has been coordinated by working groups within the International Union of Soil Sciences with technical input from the International Soil Reference and Information Centre, Food and Agriculture Organization, and national soil survey authorities such as the United States Department of Agriculture and Instituto Geográfico Nacional (Spain). Major revision rounds culminated in editions endorsed in venues such as the World Soil Congress and produced by editorial teams affiliated with institutions like Wageningen University and ETH Zurich. Ongoing maintenance relies on expert panels linked to programs such as the Global Soil Partnership and funding from multilateral donors including the World Bank and European Commission. Future updates are discussed at assemblies convened by the International Union of Soil Sciences and informed by research from laboratories at CSIRO and universities worldwide.

Category:Soil classification systems