Azieva Jamilat Serazhutdinovna  -  senior assistant, Caspian Institute of Biological Resources of the Dagestan FRC RAS, 367032, Makhachkala, M. Gadzhiev st., 45, dncran@maill.ru

Gadzhiev Islam Ruslanovich  -  research laboratory assistant, Institute of Geology, Dagestan FRC RAS, Makhachkala, 367032, M. Gadzhiev st., 45, dncran@maill.ru

Biarslanov Ahmed Biysoltanovich  -  Senior Researcher, Laboratory for Comprehensive Research of Natural Resources of the Western Caspian Region of the Dagestan Federal Research Center of the Russian Academy of Sciences, Makhachkala, 367032, M. Gadzhiev st., 45, dncran@maill.ru

Abdurashidova Pisay Abdurashidovna  -  Researcher, Laboratory of Soil and Plant Resources, Caspian Institute of Biological Resources of the Dagestan FRC RAS, 367000, Makhachkla, Hajiyeva st., 45, dncran@maill.ru

Zhelnovakova Victoria Anatolyevna  -  Researcher, Laboratory of Soil and Plant Resources, Caspian Institute of Biological Resources of the Dagestan FRC RAS, Makhachkala, 367032, M. Gadzhiev st.,45, dncran@maill.ru

The studies of the soil cover of the Tersko-Kuma lowland, located in the northern part of the Republic of Dagestan, showed the specificity and diversity of biological salinization of various degrees and types. The study of the processes of salt dynamics in the soil cover according to seasonal aspects makes it possible to identify the mechanisms that regulate the state of the soil cover. The natural content of salts in the soil and their biological diversity is associated with the nature of the genesis and largely depends on human anthropogenic activity. On the site of the territory of the Kochubey biosphere station and the coastal strip of the Kizlyar Bay, the main sections with a morphological description of genetic horizons and the selection of soil and plant samples were laid. The territory of the region under study is conditionally divided into two parts: 1) the continental part with elevations above zero up to plus 100 m relative to the world ocean level; 2) seaside - a coastal strip located in an area with minus marks from zero to minus 28 m below sea level. The soil cover, respectively, is represented by rows of automorphic and hydromorphic types of formation of light chestnut, meadow chestnut, meadow marsh soils, solonchaks, saline and degraded to varying degrees. On the continental and coastal parts, there are polygons represented by key sites. At each key site, sections were laid, morphological descriptions of genetic horizons, geobotanical descriptions of the abundance of species and the magnitude of aboveground production were carried out, and geographical coordinates were refined. As a result of the research, it was established that light-chestnut soils are slightly salinized, where the amount of salt along the profile varies from 0.070-0.188% in spring to 0.106-0.178% in summer. The presence of salt maxima of salts in the profile of a typical solonchak indicates long-term processes of salinization - desalinization (2.894% - at a depth of 25-35 cm, 2.366 - 50-60 cm). The meadow-marsh soil is distinguished by the heterogeneity of salinity along the profile. Increased salt content in the upper horizon and reduced in the lower parts of the profile. What is connected with ground moistening by the waters of the Caspian Sea and as a result of the effusion regime. The increased salt content in the upper horizon is due to chlorides. The degree of salinity of the meadow-marsh soil is very strong, the type is sulfate-chloride. According to the water extract of samples of the solonchak hummocky, it is necessary to note the seasonal dynamics of the content of dry salt residue in the upper horizon 0-10 cm 0.382-3.880% (spring-summer) and a slight decrease in autumn to 3.298%. A high salt content is observed throughout the profile, the type of salinity is sulfate-chloride. Characteristics of salinization with easily soluble salts along the soil profile are not uniform.

Key words: soil cover, salinity, salt dynamics, salt content, water extract, chlorides