TRANSFORMATION OF STRUCTURAL STATUS OF SOILS INFLUENCED BY URBOPEDOGENESIS ON THE EXAMPLE OF ROSTOV AGGLOMERATION

Soil structure, as a result of a complex system of intra-soil interactions and external influences, has undergone changes in conditions of urban pedogenesis. It affects the protective functions of the soil, the role of which increases significantly in urban landscapes. Hence, the relevance of studying the processes of transformation of the structure in urban soils is high. The composition of structural fractions and their water resistance in typical urban soils – urbostratozems (open and sealed under dense coverings) and chernozems migration-segregation of recreational zones of the city were considered in a comparative aspect. The composition and quality of the structure were studied according to the results of dry and wet sieving by Savvinov’s method. The difference in the structural status of these two groups of soils was evaluated by horizons, comparing them with each other using Student’s criterion. Taking into account the multivariate formation of urbic horizons, they were divided into 2 clusters: heavy and light in order to reduce the scatter of values. It was found that a clear sign of urbopedogenesis is an increase in the proportion of structural aggregates with a diameter >10 mm in both the urbic and buried horizons. In the light horizons of the urbic, a higher content of fractions of 0.5–0.25 and <0.25 mm was found than in the heavy ones. The buried part of the urbic soil profile, which is actually preserved under the thickness of urbic soil, migration-segregation chernozem, tends to have an increased content of clumpy fractions as a result of reducing the proportion of agronomically valuable aggregates compared to recreational chernozems. The water stability of the structure is more stable indicator. A significant increase in the content of 0.5–0.25 mm fraction as compared with native soils was found only in the buried humus-accumulative horizons due to a decrease in the share of aggregates of size >3 mm and 2–1 mm.

soil structure, migration-segregation chernozem, anthropogenic transformation, urban-soil science