Classical pedology questioned and defended

Classical pedology is increasingly being questioned about its three main components: soil classification, soil mapping, and the concept of soil as a natural body on the landscape. We discuss some of the concerns most frequently put forth, in particular the pedometric approach with its focus on soil variability and its effect on making soil classes and map units. We analyze these issues in the light of the philosophy of science and by comparison with similar issues in the field of biological sciences. Situations where soil bodies can be delineated with sharp boundaries are probably as frequent in nature as situations with gradual variations of soil properties requiring a fuzzy mapping approach. Hierarchical taxonomies are, in general, appropriate to classify soils. as they reflect the tree model that the human mind chooses to classify natural objects. Soil classification results, expressed as pedotaxa, reveal mathematical structures similar to those of biotaxa, while pedodiversity, analyzed on the basis of pedotaxa richness, follows patterns similar to those of biodiversity. Universal classifications are better communication tools to compare soils within regions than single-property maps. Classical pedology needs to evolve towards a new soil paradigm and to promote synergy with the pedometric approach.