Dr. Freddy O. Nachtergaele, Technical Officer for Soil Resources and Land Classification, Food and Agriculture Organization (FAO) of the United Nations, was e-mail interviewed
Dr. Freddy O. Nachtergaele is an agronomist who has been working for the Food and Agriculture Organization (FAO) of the United Nations in Rome as aTechnical Officer for Soil Resources and Land Classification with the Land and Water Development Division since 1989. Prior to that, he was a land resources expert for FAO in field projects in North and East Africa and in Southeast Asia. He was Vice-Chairman of the IUSS working group on the World Reference Base for Soil Resources (1994-2002) and is now member of the WRB Steering committee. At FAO he coordinates the update of the FAO/UNESCO Soil Map of the World and work on Global Agro-ecological Zoning and the Land Degradation assessment in drylands (LADA) project. He is the author of numbersous scientific articles in the field of agro-ecological zoning, land evaluation, land-use planning and soil classification.
[NJ] Dr. Nachtergaele, What is the World Reference Base (WRB) for Soil Resources?
[FN] In a nutshell, WRB is the official nomenclature of soil classification accepted by the International Union of Soil Sciences (IUSS) in 1998 (the Montpellier Congress). Consequently it has been endorsed by the Food and Agriculture Organization of the United Nations (FAO), The European Soils Bureau and West African Soil Scientists as the standard for soil classification.
The WRB facilitates the exchange of information and experience, provides a common scientific language, strengthens the applications of soil science and enhances the communication with other disciplines. The IUSS-WRB working group has continued testing the system in field excursions and in international meetings and hopes to publish a WRB revision for the 2006 IUSS Congress in Philadelphia.
[NJ] Could you briefly describe the major steps in developing the reference base?
[FN] WRB has been developed through consultation and negotiation with soil scientists all over the world. The IUSS working group started in 1980 and aimed towards the establishment of a framework through which ongoing soil classification could be harmonized. The final objective was to reach international agreement on the major soil groups to be recognized at a global scale as well as on the criteria and methodology to be applied for defining and separating them. The system is heavily indebted to the USDA Soil Taxonomy and the FAO/UNESCO (Revised) Legend for the Soil Map of the World. WRB has been tested for many years in field excursions and benefitted from discussions in international fora and peer-reviewed articles, as such it is a truly international effort to come to a common Reference System.
Historically, the WRB evolved first as an effort to develop a new independent international soil classification system (1980 - 1990), then decided to align itself with the FAO Revised Legend (and implicitly USDA Soil Taxonomy). A first draft of WRB was presented in 1994. Since 1998 it has developed a number of specific features and a structure which make it a very flexible system. Over the last five years it has been the driving force for major national systems to align themselves with many of its principles (New Russian Soil Classification, the French Referentiel Pedologique and harmonization efforts with the USDA Soil Taxonomy are ongoing), while a number of minor National classifications have simply adapted WRB as their own system. More recently demands have been made on WRB to develop beyond an international soil classification and correlation system into a basis for mapping and legends.
[NJ] What is the difference between WRB and a national soil classification system?
[FN] WRB is a reference system not intended to replace the national soil classification systems. It is primarily aimed to facilitate the transfer of soil knowledge, be it in scientific journals or in exchanges between soil scientists. This being said, it has already had a significant influence when National soil classifications were revised, and principles of WRB incorporated partly or whole.
WRB is a two-tier system of soil classification, with 30 Major Soil Groups (the "Reference Base") and 121 uniquely defined qualifiers for specific soil characteristics (the "WRB Classification System"). A set of prefixes is also established which can be added to the qualifier to indicate the depth of occurrence or the degree/intensity of expression of certain soil features.
[NJ] How much progress has been made to classify the soils of the tropics and how are these soils represented in the WRB?
[FN] Soils of the tropics have been specifically included in the WRB study/testing tours: South Africa, Burkina Faso/Ghana and Namibia. A special CD ROM on Properties and Management of Tropical Soils using WRB as Soil Classification was prepared by Professor Van Wambeke based on his standard book on Tropical Soils (Land and Water Digital Media Series # 24 information at: http://www.fao.org/ag/agl/lwdms.stm).
[NJ] How are you dessiminating information about the WRB and have you developed tangible products (books, CDs, websites) for WRB?
[FN] Yes, we have created a number of resources:
:: Empowering Soil Science Students, Educators & Professionals ::