Monitoring, comprehensive assessment of pasture desertification and their restoration in the conditions of the of the Northwestern Caspian Sea

Background. The article is devoted to a detailed analysis of the state of pastures subject to desertification in the conditions of the Northwestern Caspian Sea, which has developed specifically on heavily beaten pastures of the Republic of Kalmykia. It is noted that the main causes of degradation processes in natural pastures are both the prevailing natural and climatic conditions and an ambiguous strategy for the use of pasture lands. The purpose assessment of desertification of heavily beaten pastures of the semidesert zone of Kalmykia and methods of phytomeliorative restoration of pasture ecosystems. Materials and methods. The research was conducted according to generally accepted methods in geoinformatics and geobotany. The assessment of the distribution of sands over the territory of the eastern regions of Kalmykia was carried out using the ARC GIS software package and Landsat 9 satellite imagery data. The complex indicator is calculated using the formula W = , where Zi is a desirability of the i -th indicator; ai is its weight. The desirability of Zi for individual indicators was calculated using linear equations of the form Zi = axi +b, obtained on the basis of the functional dependence of standard desirability on the average values of ranges of pasture indicators. The weight of аi indicators was determined by the method of expert assessment. The geobotanical description of vegetation was performed on trial plots with an area of 0.25 hectares. The names of plant communities were established according to the dominant plant species, abundance according to the O. Drude scale. On the laid transects measuring 300 m x 4 m, the volume of phytomass of shrubs and semi–shrubs was taken into account by the method of model bushes, and grasses by the mowing method. Results. A map of the areas of pastures exposed to the spread of sands in the eastern regions of Kalmykia has been developed showing that the areas of sands in the Chernozemelsky, Yashkulsky and Yustinsky districts range from 648.0 – 281.3 t. ha, with a smaller area of sand distribution in the Lagansky district – 117.7 t. ha. These factors served as the basis for calculating the integrated indicator for assessing the degradation of the soil and vegetation cover of heavily beaten pastures of the republic (W), taking as a basis the natural values of the indicators: downed pastures, projective coverage, productivity of pastures. It was found that the heavily beaten pastures of the eastern zone of Kalmykia: Justinsky (W = 0.761), Lagansky (W = 0.814), Chernozemelsky (W = 0.442) and Yashkulsky (W = 0.949) districts are in a state of high soil degradation, suggesting the potential spread of sands in these territories. Conclusion. It is proposed to use phytomelioration (grasses + shrubs) in the development of open sandy massifs and depleted lands. Herbaceous and shrubby lands, with pasture-protective belts and reclamation and forage plantations, including drought-resistant species of shrub Calligonum aphyllum and semi-shrub Krascheninnikovia ceratoides, provide a projective soil coverage of 65-70% with an increase in phytomass, depending on the species composition, from 13.8 to 33.6 c/ha.