Identification of Rocky, Sandy, and Surface-Calcareous Soils in the South of the Volga Upland (Volgograd Oblast) on Satellite Images

The purpose of this work is to identify rocky, sandy, and surface-calcareous soils, using a multi-zonal satellite image, in the south of the Volga Upland in Volgograd oblast. The object of the study is the Volga–Don irrigation system within the Oroshaemaya Experimental Station. The interpretation has been performed by the spectral brightness of the space image (Pleiades) of the bare soil surface in four spectral bands. The most ranked values among them are detected in band B1 (0.43–0.55 μm). Terrain information about soils has been obtained on three catenas. It has been found that the greatest brightness (B1) is created by stones, crushed stone, and sand scattered on the surface (970–1100 units). They are followed by soils, effervescing from the surface, with strongly gravelly rocks at a depth of about 1.5 m and sandy loamy soils (710–830 units); by soils, effervescing from the surface, on mottled loams and sands at a depth of about 0.5 m (to 700 units); and by surface-calcareous soils, where mottled loams and sands are more than 70 cm deep, or calcareous material is absent in the surface horizons (560–670 units). The use of this approach will enable more detailed interpretation of soils by satellite imagery materials and discriminating the surface-rocky and sandy soils and the surface-calcareous ones. They are reflected by a similar spotty pattern on images, but differ in spectral brightness.