Contains the full lesson along with a supporting toolkit, including teachers’ notes.
The World Reference Base
The World Reference Base (WRB) for soil resources is a more recently developed system. It draws on ideas from the USDA, Russian and other systems. The basic concept is to distinguish soils according to their morphology as an expression of diagnostic features (similar to the system we now use in Ireland, but with diagnostic features that apply to soils all over the world!). The detail is comparable to that of the USDA system but it omits soil climate except in cases where the climate influences soil characteristics.
This system recognises 32 basic reference soil groups (histosols, podzols, andosols and others). Globally, the WRB system can be used as a benchmark. A soil classification derived from one system can be correlated with the WRB system and by extension with other systems.