Iodine in the soils of the basin of the inner runoff of the Kulunda plain

Abstract

The distribution of iodine (I) was studied in two soil catenae located in the basins of the Burla and Kulunda rivers in the Altai Territory. Soil sections were laid on the main types of elementary landscapes. The first site is located on a low-lying plain in a bend of the Burla River (near the village of Burla in the Altai Territory). Three sections have been laid, revealing the following soils: Calcic Kastanozems, located in the eluvial landscape, Gleic Solonetz – was formed in the superqual landscape and Chernic Gleysols Salic. The absolute height excess between chestnut soil and meadow was 3 m, the length of the catena was 677 m. The site in the valley of the Kulunda River was located in its middle course not far from the Lower Chumanka point of the Altai Territory. It had a smaller slope, so the change of soils from the top of the hilly area to the floodplain of the Kulunda River was observed at a greater distance (the length of the catena is 1650 m). The sections are laid on Gleyic Chernozems, Gleyic Solonetz Salic and Chernic Gleysols Salic, located in landscapes similar to the first catena. The total iodine content and its water-soluble form were determined in all genetic horizons. The content of total I in soils averaged 26.4 mg/kg (ranging from 0.36 to 100 mg/kg or more), water–soluble – 0.3 mg/kg, respectively (from 0.0 to 0.9 mg/ kg). It was found that the content of total I with an average strength correlates with the content of physical clay and silt, and the absolute maxima of iodine content are confined to the illuvial horizons of salt lakes. A large amount of gross iodine was also found in meadow soils, whereas iodine is found in very small concentrations in soils of eluvial positions. The identified accumulations of I in intrazonal soils can be used to cover the iodine deficiency of zonal soils by involving them in agricultural turnover as natural hayfields and pastures.