ИСТИНА

The United Nations has announced a Decade on Ecosystem Restoration from 2021-2030. The soil cover is one of the significant part of ecosystems. The importance of soil physical properties for the development of plants and other soil-living organisms requires special attention for them when studying urban soils and restoring ecosystems in urban areas. The objects of the study were clay and loamy soils of Moscow and other cities of the Russian Federation with previously unexplored soil cover (Syktyvkar, Krasnodar, Maykop, Sochi). The features of the physical properties for the diagnostic horizons previously identified by morphological properties were found. Attention is drawn to the difference in the physical properties of the horizons of re-deposited materials untreated by soil formation and humus horizons of soils was formed gradually on the daylight surface. Horizons of both types differ from the natural soil horizons and sediments in density, penetration resistance, and saturated hydraulic conductivity. The trends found for the soils of Moscow are confirmed by studies in cities of various natural zones. The density of human-made and natural horizons of sediments is higher than the density of humus urban soil horizons. The hydraulic conductivity is lower. The conditions for the occurrence of cases of very high infiltration rates are formed in old urban soils with a large thickness of humus horizons and a significant amount of waste inclusions. The trends of both improvement and deterioration of some physical properties of the horizons of reclaimed soils over time have been detected. The improvement is due to the activity of root systems and soil animals. Deterioration is as a result of people recreation and urban atmospheric fallouts (dust). Modern methods of urban soil management in the Russian Federation include constant soil material change and soil reclamation. A large number of young reclamed soil-like bodies human-constructed on the technogenic sediments of the city make the study of physical soil properties especially relevant. This research was performed according to the Development program of the Interdisciplinary Scientific and Educational School of M.V.Lomonosov Moscow State University «The future of the planet and global environmental change». Study was supported by Russian Foundation for Basic Research: Projects №№ 19-04-01298 (the study of general trends in the formation of physical properties of urban soils) and 19-29-05252 (study of the properties and short-term evolution of constructed soil-like bodies).