Classification of shallow and skeletal mountain soils with the WRB system on the example of the Trialeti Range, Lesser Caucasus (Georgia)

Abstract The aim of the paper is to evaluate the usefulness of the World Reference Base for Soil Resources (WRB) 2015 to classify shallow soils on mountains of the Trialeti Range, Lesser Caucasus, Georgia. The article also presents the evolution of the concept of Leptosols and of the qualifier “Leptic” and the diagnostic property of continuous rock. It also provides approaches to defining keys in the reference soil group (RSG) of Leptosols and identifying principal and supplementary qualifiers in WRB 2015 on example of soils of the Trialeti Range. The article gives few examples of classification for such shallow and stony soils with different set of qualifiers. Most of them fulfil the criteria of Leptosols and Regosols. These soils occur on the mountain range together with other RSGs (e.g. Pheozems). The authors propose to add the qualifier Technolithic to the list of Principal/Supplementary qualifiers of Leptosols.