The study examines the early medieval paleosol (4th–6th centuries AD) and background soil at the fortifi ed settlement of Ust-Utyak-1 located in the forest-steppe area of the Middle Tobol region. Differences in soil type were discovered. In the last 1300–1500 years, the development of forest-steppe chernozems shows a tendency towards exceeding aridity, resulting in the evolvement of leached chernozems into typical chernozems. Comparative analysis of the morphological structure and chemical properties of the soils under study gives reason to believe that the environmental conditions of the 4th–6th centuries were marked by greater humidity and heat supply than the present day. According to the historical and archaeological data, this time coincides with the fl ourishing of the Bakal Culture which declined at the end of that period.
Keywords: Paleosol, dynamics and evolution of environment, Bakal culture, Middle Tobol region.
