No 5 (2025): SPECIAL ISSUE devoted to the study of the role of natural and anthropogenic transformed soils in urban ecosystems

Soil survey of the territory of Elaginoostrovsky palace and park ensemble (St. Petersburg) in scale 1 : 500 was carried out. In total, 92 transects were laid, samples of the main types of soils were taken and their chemical properties were determined according to generally accepted methods. The connection of modern soil cover and directions of anthropogenic transformation of soils with the history of formation of different landscape areas of the park was revealed. It has been shown that, based on the park’s planning structure and historical features of its parts, it is possible to predict the spatial distribution of anthropogenic soil varieties with different thicknesses of stratified humus layers and different amounts of anthropogenic inclusions. It has been found that 23% of the studied area is under buildings and road surfaces. On the rest of the territory approximately equal shares are occupied by gray-humus stratozems (Hortic Anthrosols) and urban stratozems (Urbic Technosols), there are also slightly human transformed gray-humus gleyic soils (Gleyic Umbrisols) and humus-gleyic soils (Umbric Gleysols). Stratozems and urban stratozems have neutral or slightly alkaline environment (pH 7.0–7.5, up to 8.0 in TCN horizon), carbon content of organic compounds in surface horizons (RYur, RUur, URay, AU) is 3–4%. The stratified layers are characterized by high concentrations of plant-available phosphorus (in the Olsen extract). In many soils of the park deep intensive burrowing of the humus layer by earthworms were observed, which is typical for the Hortic horizon. The results of the conducted research allow rational organization of works on replacement of fallen old-growth trees and maintenance of existing plantations, taking into account the characteristics of soils.

Suburban forests play a crucial role in maintaining ecosystem functions and the biogeochemical cycling of elements within urban landscapes. The aim of the study was to assess the input of carbon and nitrogen from plant fall, their accumulation in litter and accumulation in soils of suburban forests of Voronezh. The studies were performed in old-growth pine and oak forests. It was found that during the summer-autumn season in oak forests twice as much carbon (12.70 t/ha) and five times more nitrogen (0.35 t/ha) than in pine forests (6.48 t C/ha and 0.06 t N/ha) is supplied. Nevertheless, element stocks in forest litter were highest in pine forests, reaching 13.70 t C/ha and 0.35 t N/ha, due to the low decomposition rate of coniferous litter. Finally, the total soil carbon stocks in the one-metre column of Gleyic Phaeozems (Arenic) of oak forests (118.2 t/ha) were significantly higher than in Someric Phaeozems (Arenic) of pine forests (65.6 t/ha). Comparative analysis revealed that the primary cause of these differences in forest soils was related to the litterfall quality and its decomposition rate across different forest types. The results highlight the leading role of forest vegetation in soil formation and carbon storage in forest soils in in the urban landscape.

The article presents the results of the study and calculation of specific reserves of organic carbon in the residential, recreational and industrial zones of the cities of the Rostov agglomeration core. The results are based on the analysis of soil samples taken from more than one hundred soil pits and boreholes, as well as more than 500 samples from the surface ten-centimeter layer. The carbon content was determined by dry high-temperature catalytic combustion. The average content of organic carbon for the upper soil horizons was determined (3.89 ± 1.11%). Its change depending on belonging to a certain functional zone was recorded. The highest content was noted in the soils of the park and recreational zone (city parks, squares and forest parks) – 4.24 ± 0.85, the lowest in the residential zone and fallow areas of the agglomeration (2.35 ± 0.92 and 2.80 ± 0.64, respectively). The analysis of its specific reserves (per unit area) was carried out, the most and least provided with organic carbon soil combinations of various functional zones were identified. The park and recreational and industrial zones of the city have the largest specific reserves, and the residential zone has the smallest – residential. It was found in it when comparing soils of different types of land use. Comparison of carbon reserves in the meter-thick soil layer of the city with literary data on chernozems of the steppe zone show similar values. The results of the study in the future will allow us to assess the role of urban soils in the regional carbon balance and the need to take them into account when planning measures to reduce greenhouse gas emissions.

The task of assessing the local carbon balance of green infrastructure elements, which is relevant for the Environmental Social–Governance green agenda, can be successfully solved using modern programmable loggers with NDIR technology for detecting CO₂ in the air. The main idea of fully automated continuous monitoring of carbon gas exchange consists in periodic pumping of atmospheric air through closed chambers for soil and vegetation, followed by exposure to assess trends in growth (CO₂ emission) or CO₂ uptake (photosynthesis) trends using in-chamber CO₂ loggers. This know-how was implemented in the Serebryanoborsky experimental forestry of ILAN RAS in Moscow on the example of planting blue spruce (Picea pungens Engelm.) on cultivated loamy sand Cambisol. Budget gas analyzers HT-401/5 (China) with registration every minute were used as CO₂ loggers. The monitoring results revealed strong changes in the plant and soil components of C-gas exchange with multiple changes in the local carbon balance from source to sink during the year. Carbon emission losses in the cold period for the soil amount to 8%, and for the plant exceed 17% of the annual flows, without completely stopping even in severe frosts. The share of gross photosynthesis of an evergreen plant exceeds 15% due to periodic winter thaws. Despite a positive annual integral estimate of about 100 gC/(m² year), the dynamics of the C-balance has a complex oscillatory character with nonlinear reactions of C-flows to temperature, which devalues the widespread estimate with rare measurements of gas fluxes and subsequent temperature extrapolation.

Zaryadye Park is a unique example of landscaping using constructed soils (technosols) based on soils and soil substrates typical of zonal ecosystems from various climatic zones of the European part of Russia. Soil samples (0–10 cm) from landscape analogs were analyzed to determine a range of agrochemical (pH, organic matter content, and nutrient levels) and microbiological (microbial activity, functional diversity, diversity of cultivable mycobiota, including opportunistic pathogens) parameters. The obtained soil parameters were compared with those of zonal soils from corresponding natural landscapes. For most landscapes, a decrease in organic matter content, an increase in pH and available phosphorus levels, and a significant reduction in potassium content, respiratory activity, and microbial biomass were observed compared to natural analogs. Functional diversity increased in soils with a more acidic pH. The cultivated microfungal community in the landscape analogs exhibited low species diversity (Shannon indices up to 1.9) and specific mycocomplex compositions (Jaccard indices up to 0.5). In September, the number of microfungal species increased in most zones, accompanied by a rise in the proportion of conditionally pathogenic species (from 44% in May to 68% in September) and an overall decline in species richness (from 26 species in May to 19 species in September). The conducted analysis demonstrated that soil constructions mimicking the soil cover of corresponding natural landscapes, under unified climatic conditions and intensive anthropogenic pressures, form unique biotopes distinct from both natural ecosystems and standard urban parks. These biotopes possess specific chemical and microbiological compositions, requiring thorough monitoring and management to maintain ecological sustainability.

Assessment of the enzymatic activity of constructed soils (constructozems) was performed during the second year of their functioning at the “Experimental Station for Study of Soil Constructs” in the Botanical Garden of the Southern Federal University (Rostov-on-Don, Russia). The station consists of 15 autonomous plots representing five different variants of soil constructions created using sand, humus-accumulative horizons of chernozem, loess-like loam, and high-moor peat. These substrates are traditionally used for landscaping and urban greening purposes in steppe zones. The Haplic Chernozem, located on a watershed plot in the vicinity of the Experimental Station, was studied as a background area. The activities of dehydrogenase, phosphatase, catalase, β-glucosidase, and the intensity of fluorescein diacetate (FDA) hydrolysis were analyzed for the soil constructions and the reference soil. The most informative characteristics of the constructozems were activity of β-glucosidase, catalase, phosphatase, and FDA hydrolysis intensity. Enzymatic activity allows an assessment of the stability of the constructed soils, as well as intensity and direction of biochemical processes occurring in the constructozems. Enzyme activity depends on the substrates used during construction, their combinations, thickness, and the horizon sequence. Some variants of constructozems demonstrate levels of enzymatic activity close to the natural zonal soil (background), indicating functional stability and their ability to perform ecological functions under the climatic conditions of the Rostov Region.

Chemical, biological and toxicological parameters of the soils (gray-humus stratozems, or Hortic Anthrosols, and urbostratozems, or Urbiс Technosol) of the Russian Museum gardens were investigated (Summer Garden, Mikhailovsky Garden, Engineering Square). It has been established that these soils are highly fertile, characterized by environmental sustainability and have a high buffering capacity for pollutants. The content of pollutants (oil products, heavy metals, benz(a)pyrene) in the soils of the Russian Museum gardens exceeds the MAC and APC standards established in the Russian Federation. However, according to the results of biotesting on daphnia, unicellular algae and higher plants, all the soils studied are non-toxic. Water extracts from the studied soils have a reliable stimulating effect on the seeds of higher plants and green algae, increasing their growth by 30–50%. This is due, in our opinion, to the richness of the soil in nutrients and water-soluble humic substances. The results of determining heterotrophic (microbial) respiration show that the studied soils are characterized by stable and balanced functioning, as well as high ecological stability of the microbial cenosis to anthropogenic impact. It is necessary to correct the standards for the pollutants’ content in urban soils, basing such correction on the soil’s actual quality and health assessment at different levels of pollution.

For the first time, the contamination of the soil cover of Ulan-Ude, the capital of the Republic of Buryatia, with polycyclic aromatic hydrocarbons (PAHs) was studied. The work is based on the materials of the soil-geochemical survey of Ulan-Ude in the summer of 2022. Analysis of the content of 17 individual PAHs in 220 samples showed the levels of their accumulation in the upper (0–10 cm) soil horizons of different land use zones of the city. The average amount of PAHs in the soil cover of Ulan-Ude was 801 ng/g, exceeding the background concentration by more than 8.5 times. In terms of total PAH content, the land use zones form a series: transport railway (2250 ng/g) > industrial, motor transport (873) > residential single-story (860) > residential multi-story (530) > recreational (444). The composition of polyarenes is dominated by medium- (43%) and high-molecular (46%) compounds. Among polyarenes, medium- (43%) and high-molecular (46%) compounds dominate. Using the PCA/ APCS-MLR model, three components were identified that control the accumulation of PAHs in the city soils. The first explains 76.8% of the total variance and includes all high-molecular PAHs, as well as 4-nuclear benz(a)anthracene and chrysene, formed during the combustion of wood and coal in private buildings, coal at thermal power plants, industrial combustion of oil and contained in emissions from motor and rail transport. The contribution of the second component is 13.7%, it is due to low-molecular PAHs and reflects the contribution of forest fires and petrogenic sources, including coal dust. The third component is associated with the accumulation of phenanthrene, fluoranthene, pyrene and chrysene, resulting from the combustion of wood, coal and diesel fuel. An assessment of the environmental hazard of the studied PAHs, expressed in terms of benz(a)pyrene equivalents, showed that the MPC for benz(a)pyrene was exceeded in their sum on 63% of the city’s territory; the excess factor in soils varied from 1.1 to 63.9 with an average value of 5.7.

The level of chemical pollution of the surface part of soils with heavy metals (Co, Mo, Cd, Ba, Cu, Ni, Pb, Cr, Zn and Mn) and petroleum products in Petropavlovsk-Kamchatsky in 2023 was determined. The use of various ecological and geochemical approaches for a comprehensive assessment of the state of the urban environment revealed different degrees of pollution in the study areas depending on the pollutant and the calculated indices. The maximum content of class I hazard pollutants in the soil was 1546 mg/ kg for petroleum products, 3.37 mg/kg for Cd, 248 mg/kg for Pd, and 571 mg/ kg for Zn. Anthropogenic sources of their intake were identified. In general, the comprehensive assessment conducted using geochemical, toxicological indices and phytotesting determined the city’s soils as slightly polluted. At the same time, in certain areas associated with the automobile infrastructure and fuel and energy complex enterprises, a high degree was established both by comprehensive indices and by external pollutants (Pb, Zn). The maximum soil pollution with brittle metals was noted when calculating the ecological and geochemical indices and amounted to 13% (by the Zc index) to 80% (by the NPI index) of the total number of measurements. The excess of oil products in soils was insignificant and 6.6% of soils were determined as polluted. Comparative analysis of integral indicators of the current ecological state of soils. Petropavlovsk-Kamchatsky has identified a number of methodological problems in assessing the level of pollution. For the regional center and Kamchatka Territory as a whole, one of the main difficulties is taking into account regional geochemical levels of both heavy metals and oil products in soils. Given the influence of active volcanism, both in the geological past and in the present of the peninsula, identifying background values for the content of a number of pollutants is an urgent task for conducting objective environmental monitoring of the soil cover in the region.