Characteristics of fluorine content and distribution in soil catenas in the south of the kulunda plain

Content and distribution of fluorine (F) were studied in 2 soil catenae located in the basins of the Kuchuk and Suetka rivers. Soil sections were laid on the main types of elementary landscapes. In the valley of the Kuchuk river, the key site is located near the village of Stepnoye in the Altai Territory. A section of chestnut soil is laid in the eluvial zone, an alluvial saline soil is laid in the transit zone, and a section of floodplain alluvial soil is laid in the accumulative zone. In the valley of the Suetka river, the key site is located near the village of Verkhnyaya Suetka in the Altai Territory. Three sections were laid: chestnut brackish, light-brown cortical and meadow-marsh soils in eluvial, transit and accumulative positions, respectively. The total content of fluorine and its water-soluble form were determined in all genetic horizons of the meter profile of soils. The high content of fluorine in the catena of the Kuchuk river was noted in the arable horizon of chestnut soil, which is associated with the introduction of fluorinated fertilizers. In the catena of the Suetka river soils, the maximum amounts of gross and water-soluble fluorine were in the saline and sub-saline horizons, which is associated with the accumulation of halogen on the geochemical barrier. The statistical processing of the data confirms that the processes of accumulation and migration of fluorine in the soil are determined mainly by the reaction of the soil environment, granulometric composition (content of physical clay and silty fraction), as well as soil salinity. At the same time, the content of gross and water-soluble fluorine in the soils of the studied area corresponds to an ecologically acceptable level.