Ландшафтно-геоморфологические особенности балочных систем, развитых в песчаных отложениях южной части Приволжской возвышенности

The article deals with the morphological features of the profile and slopes of ravine systems developed in sand deposits of the southern part of the Volga Upland. The author notes that the southern part of the Volga Upland is a vast inter-river space bounded bythe river valleys of the Don and the lower reaches of the Ilovlya river in the west and the Volga river and Volgograd reservoir in the east. This area has a potential for water and wind erosion. This is determined by the features of the geological structure (the development of Cenozoic Eocene-Oligocene marine deposits represented by alternating layers of clays, siltstones, sandstones and sands and Neogene-Quaternary sand-loam covers), as well as hilly type of terrain. The density of the erosion net here is 0.8-1.0 km/km2. The ravine and river valleys of the territory under consideration are typified bythe age and morphological criteria into 4 types: middle and late Pliocene valleys of the Don drainage basin; Pleistocene valleys of widespread distribution; late Pleistocene valleys of the Don drainage basin; modern Holocene erosional forms. Broad floodplains with sandy loam alluvium, flattened valley slopes, and trough-shaped cross-sections are noted as common features of the structure of ravine and river valleys. The role of deflation and water erosion in the evolution of the slope microrelief of erosion forms is analyzed. The role of ravine systems in the formation of natural-territorial complexes of psammophytic steppes with a significant share of rare plant species, as well as the spread of bayrachny forest in the dry-steppe zone is noted. The predominant role of such natural-territorial complexes as psammophytic sagebrush-cereal sparse steppes on the sod- sandy soils of the Don above-floodplain terraces; sparse dry sheep fescue and white artemisia steppe on the light mechanical composition of the soils of the Ergeninsk sands on the ravine slopes is noted. Among the intrazonal natural-territorial complexes, ravine and floodplain poplar-oak and old-growth aspen-poplar forests are distinguished.