A universal soil classification system from the perspective of the General Theory of Classification: a review

Abstract The paper addresses issues related to the application of the General Theory of Classification in the development of a universal soil classification system. The requirements for such a system, a comparison of different approaches to its development, and obstacles on the way to it are outlined. Additionally, the problem of the definition of soils and the importance of distinguishing between differentiating and diagnostic criteria are discussed. It is shown that, from the perspective of the General Theory of Classification, a universal soil classification system should be natural, genetic, “fundamental-and-specific”, and hierarchical. It is concluded that the World Reference Base for Soil Resources (WRB) does not meet these requirements and therefore cannot be considered as universal. Ways of addressing the problems of a universal soil classification system are suggested.