Water-Regime Formation in Sands of the Archeda–Don Massif with Respect to the Distribution of Plant Formations

Remote monitoring and landscape–environmental profiling of the Archeda–Don sand massif made it possible to assess the state of the soil–vegetation cover and to determine the groundwater level and inclination. The degrees of soil salinity were identified for various sand types. The salinization of chernozem-like soils reaches 0.05%. The salinization of sand massifs with large amounts of litterfall is 0.05–0.07%. In open sands that formed in depressions as a result of blowing, the salinity does not exceed 0.001%. Pine outliers and planted stands are widespread throughout the sand massif. Natural forest stands consist of the following species: Betula pendula , Alnus glutinosa , Quercus robur , Populus tremula , and Salix spp. ( S. fragilis , S. reptans , S . carpea , and S . rosmarinifolia ). Pinus sylvestris plantings were introduced in the 19th century. The large number of forest sites and their outlier-based distribution are determined by the proximity of groundwaters. Black alder ( Alnus glutinosa ) stands reach the maximum productivity with a timber volume of up to 500 m 3 /ha. In areas with stagnant groundwaters, their height is 12–15 m. Birch ( Betula pendula ) outliers are located in depressions. Sparse European oak ( Quercus robur ) standing 8–12 m high occur on clayey sites. It is shown that Pinus sylvestris grows optimally on chernozem-like sandy loam soils and on single-phase, overgrown sands with thick, sod–steppe soils. Five dominant types of sands have been distinguished. The total area of forage lands within the sand massif is 171 536 ha; their herbage productivity is 370 700 t. The total area of forest sites is 50 584 ha. Overgrown hummocky–ridgy sands predominate. Overgrown closed depressions and ancient watercourses feature the highest productivity (3.0 t/ha). The results are essential for the development of a conceptual model for the optimal use of sandy lands.