Selenium in the soils of the Taganay national park and the Tyumen state reserve

Selenium is the most important trace element in the body of plants, animals and humans. In this regard, the study of selenium in soils and vegetation of territories unaffected by anthropogenic impact, which are specially protected natural territories (protected areas), is of great theoretical and practical importance. The Tyumen State Nature Reserve and the Taganay National Park were chosen as the study areas. In these territories, the gross content of selenium in the upper horizon of soils (0-20 cm) was studied. The analysis of selenium content in plants was carried out in the Taganay National Park for the three most common plant species of the herbaceous tier in the study area - cane vine (Calamagrostis arundinacea), common sour (Oxalis acetosella L.), common blueberry (Vaccinium myrtíllus L). The plants were selected at the same sites as the soil samples. The selenium content in soil and plants was determined in the branch of FSBI “TsLATI in the Ufa region” in the Tyumen region by inductively coupled plasma spectrometry using a Varian 720 - ES spectrometer. Despite the significant biogeochemical differences of the studied protected areas, the selenium content in the soils of the studied territories does not differ significantly and ranges from 0.01 to 0.09 mg/kg, with average values of 0.05±0.02 and 0.062±0.02 mg/kg, respectively, in the soils of the Taganay National Park and the Tyumen State Reserve. The studied soils of protected areas are selenium-deficient. This may be one of the reasons for the lack of selenium in the soil-plant system. The total content of selenium has a pronounced relationship with the humus content in the soils of the Tyumen State Reserve and with the level of acidity in the soils of the Taganay National Park. The selenium content in the most common herbaceous plants of the Taganay National Park varies within insignificant limits and does not differ significantly, both in species composition and in relation to functional zones. The generalized selenium content in plants is at the lower limit of availability (0.051-0.054 mg/kg of dry matter). According to the calculated absorption coefficient, these plants for the accumulation of selenium belong to groups of weak capture. The low content of selenium in the studied plants of the Taganay National Park is associated with a shortage of this gross content of the element in soils and, apparently, with a low content of its water-soluble forms.