The article presents datas on the gross chemical composition of buried soils of Subatantic and Subboreal periods, that’s located on geosystems floodplain of the Middle Volga. Based on the evaluation of geochemical factors justified bioclimatic conditions of their development, as well as the peculiarities of the process of soil formation. The comparative geochemical characteristics of buried soils with their zonal analogues (leached chernozem).