Pavel Petrovich Krechetov

The aim of this study was to assess the intensity of organic matter transformation in urban soils affected by motor transport. Comprehensive seasonal terrain studies were performed in 2023‒2024 in the southwest of Moscow (Russian Federation). Chemical properties and biological activity of soils were studied. Two indicators—cellulolytic activity and biological oxygen consumption—were used to assess the biological destruction of organic matter. The pH value of roadside soils was 7.8 ± 0.6, the electrical conductivity was 185 ± 98 μS/cm, and the organic carbon content was 4.8 ± 2.1%, which corresponded to published data on urban soils in Moscow. It was revealed that the biological activity of soils of roadside lawns and median strips was characterized by significant dispersion of values: from 38 to 87%, depending on the season. The rates of cellulolytic activity in roadside soils were the highest in the summer-autumn and spring observation periods: 11.9 ± 7.6 and 12.0 ± 3.0 mg mg/g of organic matter per day (mg/(g day)), respectively. During the cold season, it was several times smaller: 4.1 ± 3.1 mg/(g day). In spring, the biological activity of urbo-soddy-podzolic soils (Retisols (Technic)) in central parts of large urban greenery areas was six times lower than in roadside soils. In other seasons, no reliable dependences were found between the studied indicators and the traffic intensity. The leading factors, determining the intensity of organic matter biological decomposition in urban soils under the impact of motor transport, include specific soil formation in constructozems (Technosols), urban microclimate, and differences in geochemical features of roadside soils due to chemicals applied during road maintenance works.

The aim of the study was the assessment of the intensity of organic matter transformation in urban soils impacted by auto transport. Thorough seasonal field studies were carried out in 2023–2024 in the southwestern part of Moscow (Russian Federation). The chemical properties of soils, as well as their biological activity, were studied. For assessing organic matter biological destruction two indicators were used, cellulolytic activity and biological oxygen consumption. The pH value of roadside soils was 7.8 ± 0.6 units, electrical conductivity was 185 ± 98 μS/cm, and the organic carbon content was 4.8 ± 2.1%, which corresponds to literary data on urban soils in Moscow. It has been revealed that the biological activity of soils of roadside lawns and median strips is characterized by significant dispersion of values, from 38 to 87%, depending on the season. The highest rates of cellulolytic activity in roadside soils were determined in the summer-autumn and spring observation periods, 11.9 ± 7.6 and 12.0 ± 3.0 mg of readily organic matter mg/(g day), respectively. During the cold season it was several times less, 4.1 ± 3.1 mg/(g day). In spring the biological activity of urbo-soody-podzolic soils (Retisols Prototechnic) in central parts of large urban greenery areas was 6 times lower than in roadside soils. In other seasons, no reliable dependences were found between the studied indicators and the intensity of traffic. The leading factors determining the intensity of organic matter biological destruction in urban soils under the impact of auto transport are specific soil formation in constructozems (Technosols), urban microclimate, as well as diversity in geochemistry of roadside soils due to applying chemicals in roads maintenance work.

One of the most important challenges for soil science is to determine the limits for the sustainable functioning of contaminated ecosystems. The response of soil microbiomes to kerosene pollution is still poorly understood. Here, we model the impact of kerosene leakage on the composition of the topsoil microbiome in pot and field experiments with different loads of added kerosene (loads up to 100 g/kg; retention time up to 360 days). At four time points we measured kerosene concentration and sequenced variable regions of 16S ribosomal RNA in the microbial communities. Mainly alkaline Dystric Arenosols with low content of available phosphorus and soil organic matter had an increased fraction of Actinobacteriota, Firmicutes, Nitrospirota, Planctomycetota, and, to a lesser extent, Acidobacteriota and Verrucomicobacteriota. In contrast, in highly acidic Fibric Histosols, rich in soil organic matter and available phosphorus, the fraction of Acidobacteriota was higher, while the fraction of Actinobacteriota was lower. Albic Luvisols occupied an intermediate position in terms of both physicochemical properties and microbiome composition. The microbiomes of different soils show similar response to equal kerosene loads. In highly contaminated soils, the proportion of anaerobic bacteria-metabolizing hydrocarbons increased, whereas the proportion of aerobic bacteria decreased. During the field experiment, the soil microbiome recovered much faster than in the pot experiments, possibly due to migration of microorganisms from the polluted area. The microbial community of Fibric Histosols recovered in 6 months after kerosene had been loaded, while microbiomes of Dystric Arenosols and Albic Luvisols did not restore even after a year.

This paper examines effects caused by erosion products and seepage waters spreading from sulfuric coal dumps for more than 50 years on the chemical composi

The subject of this study is the ratio of carbon and nitrogen content in the soil of the lithalsa landscape in the Sentsa River valley. The focus is on the spatial distribution of C/N ratio in the genetic soil horizons: humus (A), illuvial (B), the parent rock(C), as well as in the buried peat horizon (T). The carbon and nitrogen content is analyzed in 70 samples using the element analyzer C, H, N, S –O EA 1110. Sample preparation included drying the soil through a sieve and grinding it with a rubber pestle in a porcelain mortar. It is found that cryogenic concentration of soil solutions, cryogenic heaving, thermokarst, zoogenic turbations, peat burial, and alluvial loam deposition are the main processes determining the peculiarity of soil formation within lithalsa landscapes. The maximum variation in the ratio of carbon and nitrogen content is observed in the illuvial horizon, while in the humus horizon and in the parent rock, as well as in the buried peat horizon, this indicator is of a smaller range.