Traces of Ancient Anthropogenic Activity in the Soils (on the Example of the Bronze Age Settlement Arbakol-1 in the Kislovodsk Basin)

The purpose of this work was to identify traces of ancient anthropogenic activity by assessing the biological activity of the cultural layers of settlement Arbakol-1 of the Bronze Age in the soil catena vicinity of Kislovodsk. One soil section on the territory of the settlement at the foot of the slope and three soil sections in the potential economic zone of the settlement in the upper, middle, and lower part of the slope were studied. In the soil profiles, the content of ceramics in cultural layers was evaluated, the physicochemical properties (magnetic susceptibility, organic carbon content, organic and mineral forms of phosphorus) and biological activity (biomass of active microbial cells that give a respiratory response to the introduction of glucose, the abundance of living microbial cells, phosphatase and urease activity) were evaluated. The site of a potential economic zone near the settlement of Arbakol-1 in the upper part of the slope has hardly preserved any traces of ancient agriculture due to erosion processes that have sharply intensified during plowing. Rather high values of urease activity in this case are probably associated with modern cattle grazing. In the middle and lower part of the slope, the most favorable conditions existed for the growth of the soil profile and the accumulation of erosive material. At the same time, there was a natural conservation of traces of agricultural development of the territory: ceramics, living microbial biomass, phosphate content, and, to a lesser extent, magnetic susceptibility. Such biological indicators as the enzymatic activity and the biomass of active microorganisms that give a respiratory response to the introduction of glucose do not reflect the fact of agricultural development of the territory in the Bronze Age. In the cultural layer on the territory of the settlement, the highest occurrence of ceramic fragments and the maximum values of all the studied parameters are shown, with the exception of phosphatase activity, which is related to the high content of mineral forms of phosphorus.