Soil distribution and soil properties in the subalpine region of Kazbegi, Greater Caucasus, Georgia: Physicochemical properties, distribution and genesis

Abstract

Due to their characteristic properties, mountain soils require adequate management if used for cropping or grazing, even if climatic conditions are favorable. This study provides a summary of a three-year field campaign that evaluated mountain soils in in northern Georgia for sustainable agricultural use. Soils in the Kazbegi study area, located on the northern slope of the Great Caucasian Ridge, were mapped in 2014 and 2015. The soils developed mainly on sediment fans and on glacial and fluvial sediments. They were characterized by a low to moderate yield potential, with high-yield soils found on volcanic plateaus. Despite the high diversity of terrestrial and semi-terrestrial soils, common to all of them was a high humus content. In the river valleys, Fluvisols (or at least soils with fluvic-properties) were widespread and in the valley depressions fens, e.g., Histosols, occurred as well. On volcanic substrates, medium to very deep Cambisols or Umbrisols were found, with moderate to good agricultural yield potentials. However, P-sorption, mainly on amorphous Al- and Fe-oxides, could lead to an increased need for fertilization. Cambisols were present on moraine, and primarily Regosols and Cambisols on the clay and silt-rich sedimentary rocks of the Jurassic, including a widely distributed coarse fraction. The cambic horizon was not visually apparent but was clearly detectable analytically. Depending on the slope inclination and exposure, even Leptosols occurred on the slopes and peaks of sedimentary or volcanic rocks. Based on these results, a synthetic soil map merging geological and geodetic data as well as data from field mapping was created to provide an instrument for land use management.