Increasing the Efficiency of Plant-Cover Restoration in the Modern Focus of Deflation on Pastures of the Northwestern Caspian Region

Abstract

The change in the use of forage lands in the Black Lands and the Kizlyar pastures of the Caspian Sea region in the second half of the 20th century from winter to year-round, their overload with livestock, and plowing for forage crops led to the degradation of natural ecosystems, an outbreak of light-soil deflation, and the formation of large foci (with an area of ​​hundreds or thousands of hectares) of fine sands. The development of new technologies and the implementation of large-scale studies on their phytomelioration in the 1970–1990s made it possible to restore the vegetation cover on an area of ​​over 400 000 hectares and to stop the avalanche-like desertification of lands. However, the productivity and nutritional benefits of secondary phytocenoses obtained large differences. The article reveals the morphoecological specificity of the development and the water-physical properties of the soil of modern deflation foci. The technologies of their shrub and complex phytomelioration are considered. The formation features, biological diversity, productivity, and stability of the secondary vegetation cover were determined based on materials from the long-term monitoring of successions. The advantages of complex phytomelioration, including the use of woody, semishrub, and herbaceous plants, have been found. It was found that the created regenerative fodder ecosystems produce 2.0–5.0 t/ha of hay in the first 5–10 years and develop according to the shrub–herb type. Their floristic composition expands to 30–50 species in the subsequent decades. Their productivity decreases to 1.0–2.0 t/ha but depends less on the amount of precipitation than in virgin areas. Forage (up to 55%) and medicinal (up to 12%) plant species prevail in the 20- to 30-year-old phytocenoses. Pamirian winterfat has a high coenosis potential and stability. Pastures with its participation are distinguished by the stability of the pasture stock in terms of the composition and years of observation. At the same time, the indigenous species of valuable pasture plants (forage kochia, wormwood, and perennial grasses) slowly penetrate the cover of “extinct” deflation foci. It is necessary to improve the methods of their primary phytomelioration and to reconstruct a low-value vegetation cover on fixed sands. Measures to improve the technologies of primary phytomelioration of modern foci of deflation should be based on the expansion of the range and the joint use of valuable forage shrubs and perennial psammophilic grasses, the effective protection of local regenerative forage phytocenoses from sand transfer, the creation of a shady tree layer, the organization of moderate grazing of the secondary cover in subsequent years, and stimulation of the spread of indigenous grazing plant species.