Specific Features of Organic Horizons in Surface and Buried Soils within Residential Areas in the City of Perm

The history of Perm city is imprinted in surface and buried soils, especially in their organic horizons, as these surface horizons are most strongly affected by the anthropogenic impact. Similarities and differences in morphology and properties of surface and buried organic horizons have been revealed for the soils of Perm residential areas. They depend on the functional role of soil cover in residential areas, the type of urban buildings, and the use of particular construction materials. The differences are manifested in the presence and composition of artifacts; the contents of organic carbon, carbonates, and available phosphates; and soil pH. In the buried organic horizons, the intensity of soil respiration and the urease activity decrease and are lower than in the surface organic horizons, whereas the urease activity is relatively high. Additional input of organic matter to urban soils increases the content of humic acids in organic horizons and the degree of organic matter humification to a high level. The soils without additional input of organic matter display the features of zonal humification processes of low and medium intensity. The anthropogenic contribution to the carbon cycle has increased with the widespread use of peat for reclamation, as well as carbonate building materials.