ECOLOGICAL STATE OF PASTURE LANDS IN ARID REGIONS OF THE STAVROPOL TERRITORY

Abstract

The purpose of the research was to study the ecological state of the vegetation cover of the steppe phytocoenoses of the Kursky and Stepnovsky districts of the Stavropol Territory, which were used as pasture lands, and to offer recommendations for their use and improvement. An aboveground geobotanical survey of vegetation of steppe communities was conducted in 2022-2023. For this purpose, the method of trial registration plots with an area of 10x10 m² was used, on each of which vegetation descriptions were carried out using the abundance determining method according to the O. Drude scale. The yield of aboveground phytomass was assessed on a registration plot of 0.5 m² in a 4-fold replication. The criteria for identifying the stages of digression were the following indicators: species wealth per unit area, the proportion of steppe species in the plant stand, the proportion of weedy species in the plant stand, and plant cover disturbance. It was found out that the steppe vegetation of the studied territory was homogeneous in terms of flora composition and low-growing. The projective cover of the soil surface by plants was from 40 to 80 %. The number of species per registration plot was from 15 to 29 units/100 m². The stages of pasture digression were established in the range from weakly trampled (stage I) to very heavily trampled (stage IV). The results of the yield of the aboveground phytomass of the studied pasture lands were obtained, which ranged from 5,8 to 22,5 dt/ha of air-dry mass. The highest yield of aboveground phytomass was observed in Ali-Kuiu and Olgino. The lowest yield of the plant stand with its maximum digression (stage IV) was noted in the Sernovodskoe pastures – 5,8 dt/ha of air-dry mass. The yield of the aboveground mass of the studied plant communities, taking into account the coefficient of plant stand consumption, averaged 8,7 dt/ha in the dry eaten mass, with fluctuations from 2,9 to 11,3 dt/ha. In the current ecological situation, the steppe plant stand of the studied territory, depending on the stage of pasture digression, needs rational use [I, II stages] or improvement (restoration) [III, IV stages], in order to prevent further processes of digression and increase the bioproductivity of pasture lands.