Geochemical features of alluvial soils of the middle reaches of the Bolshaya Kokshaga river

The article presents the results of work on the identification of the paragenesis of chemical elements and radial geochemical barriers in the basic alluvial soils (Fluvisols) of the middle reaches of the Bolshaya Kokshaga River (Republic of Mari El). It was found that the leading (typomorphic) element is Fe, with which Mn, Ba, P, Zn and Ni are associated. Al forms a geochemical family with K, Mg, Ti and Cr. The content of Ca, S, Sr and Cu is related to the amount of loss during calcination, and Na and Zr are related to Si. Particular elements are fixed on radial geochemical barriers: Si and Zr on the mechanical, Ca, S, Sr and Cu on the biogeochemical, Al, K, Mg, Ti and Cr on the sorption, Fe on the oxygen and Mn, Ba, P, Zn and Ni on the chemisorptions one. The peak concentrations of Si and Zr were recorded on mechanical barrier in the profile of all types of soils. Ca, S, Cu and Sr are fixed on the biogeochemical barrier in turf and swamp soils. Increased concentrations of Al, K, Mg, Ti and Cr were found on the sorption barrier in all types of soils. The effect of oxygen and chemisorption barriers reveals itself in meadow and humus-gley soils.