Pedogenic response to Holocene landscape evolution in the forest-steppe zone of the Russian Plain

Abstract

Soils buried under five defensive ramparts of the Early Iron and Middle Ages were studied in the forest-steppe zone of the Russian Plain (Lipetsk region, Russia). The time of the burial differs from each other for hundred years allowing studying variation of soil properties based on short-term chronosequences within these ranges and reconstructing the comparatively short climatic trends. Similar topographic positions, particle-size distribution, bulk elemental composition, and major morphological features were the base for comparing buried and surface soils, aiming to link the differences in the pedofeatures with climatic fluctuations. The studied soils display polygenetic features that were formed under forest (clay cutans) or steppe (carbonate neoformations, mollic horizons) environments. Generally, the Early Iron Age environment was similar to the modern one, which is confirmed by the similarity between the soil buried ∼ 2500 yrs BP and the surface soils (Greyzemic Luvic Phaeozems). The detailed chronosequence allows distinguishing alternating humid and arid phases during the studied time interval. Soil response to climatic phases is recorded by rather dynamic pedofeatures: carbonate, gypsum and greyzemic properties, and the properties of the mollic horizon. Following climatic fluctuations, these pedofeatures can appear and then be erased or transformed, evidenced by a multi-layered cutan complex with alternating clay and carbonate coatings. As a result, the surface soils of the study area are polygenetic and combine features formed under steppe and forest environments. The alternating phases of forest and steppe pedogenesis throughout the entire Holocene, especially in the Late Holocene, when ancient tribes influenced the studied areas, testifies against the decisive role of anthropogenic input in the formation of Chernozems.