Content and Distribution Features of Fluorine and Iodine in the Profile of Chernozems of the Pre-Salair Drained Plain

In the studied chernozems of the Pre-Salair drained plain, the total fluorine content varies from 286 to 431 mg/kg, and the total iodine content ranges from 0.9 to 3.2 mg/kg. The obtained parameters basically correspond to the average content of these halogens in the soils of the world. It has been established that humus plays a priority role in the process of iodine accumulation, while the other studied soil properties have no effect on the distribution of iodine in the profile of chernozems. The distribution of total fluorine in the profile of chernozems is influenced by the granulometric composition, the reaction of the medium and the calcium geochemical barrier on which fluorine is deposited. The accumulative carbonate horizon has the highest content of gross fluorine – 401–431 mg/kg. The most uniform distribution of halogens along the profile was found in virgin chernozems. The profiles of fallow and arable chernozems are moderately differentiated in terms of halogen content. In the studied chernozems, the content of gross fluorine is environmentally acceptable, while the content of gross iodine is insufficient.