Olga Vyacheslavovna Semenyuk

The influence of recreation on carbon (C) and nitrogen (N) reserves in the litter and upper mineral horizons of soils of larch stands in Izmailovsky Park, Moscow, was studied. The objects of study - a recreationally disturbed larch forest (third stage of digression) and a control larch forest (first stage of digression). The following indicators were determined: carbon and nitrogen reserves in all litter subhorizons, as well as in different fractions of subhorizon L, reserves of total and labile C and N in the 0–10 cm layer of the mineral part of the soil profile. It has been shown that under recreational load, the accumulative role of litter decreases compared to the control, and the difference in the reserves of C and N in litter by the components of tesserae is leveled out. The decrease in the reserves of C and N in litter is determined by the decrease in the total reserves of the litter itself. Significant losses of C and N from the humified and fermentative litter subhorizons due to recreation were detected. Maximum C and N losses from the litter correspond to the near-trunk spaces. Within the L-F-H litter profile, maximum losses are observed in the humified subhorizon in the sub- and inter-crown spaces. Under recreational loads corresponding to the third stage of soil degradation, no changes in C and N accumulation in the upper mineral soil horizon were recorded.

The article presents the results of a study on the dynamics of the height, reserves, and chemical composition of snow cover within the megapolis (Moscow) and conditionally background territories of the Solnechnogorsk district of the Moscow region (Educational and experimental soil and ecological center of Lomonosov Moscow State University “Chashnikovo”) for the winter-spring period of 2023–2024.

The study objects included: the drainage divide area of the Klyazma River in conditionally background conditions and two types of soil lysimeters from the Faculty of Soil Science of the Lomonosov Moscow State University located within Moscow. The first type of lysimeters was characterized by various soil cultivation methods under continuous operation in meadow mown phytocenosis conditions. The second type of bulk lysimeters were situated under different land use types (bare fallow, fallow land, overgrowing fallow land, spruce plantations, mixed, and broad-leaved forests) formed on a uniform mineral matrix represented by cover loam.

The dynamics of snow cover exhibited similar patterns in both natural and city conditions: maximum snow reserves occurred in February, followed by a decline in spring. Minimum snow reserves were observed in lysimeter areas with spruce plantations, while maximum reserves were recorded in treeless areas, including grass fallow and lysimeter plots under various soil cultivation conditions. In urban environments, significantly higher concentrations of certain alkali and alkaline earth elements (sodium, calcium, strontium), as well as zinc and copper, were detected. The concentrations of the most mobile anions, particularly chlorides, in the snow water of the megapolis exceeded those in natural conditions by 2–3 times. This is consistent with the higher pH and electrical conductivity values for snow water in urban settings.

The type of phytocenosis played a key influence in the spatial distribution of snow and its components. Coniferous and mixed forests retained more snow, which reduced the migration of lysimetric waters, whereas broader-leaved and open areas experienced more intense snow accumulation and vertical water migration.