On some theoretical problems of classification and geography of soils in connection with the concept of the soil individuum

The object of natural hierarchical classifications of soils of the world is not the soil cover and its components as physical bodies, but our knowledge of them. The entirety of this knowledge constitutes the abstract soil-classification space. Classification is one of the means of systematizing and structuring our knowledge. One should distinguish between the objectivity of a classification, which is conditioned by its theoretical level, and the reproducibility of a classification, which is ensured by the development of a quantitative diagnostics of taxa and standardization of the procedure of soil diagnostics. In this article, the concepts of the classificatory-diagnostic soil individuum, the soil-geographic individuum, and the elementary areal of soil combination are discussed in the context of the general problem of soil classification.