Articles

It is shown that time has always been considered by soil scientists as a “special” factor of soil formation — the form of the soil's existence as a material body. Soil formation processes are almost always nonlinear in time and cyclical (often this cyclicity is interrupted by the flow of soil formation). The soil, as a natural body, on the one hand, obeys the internal laws of self-development (in particular, the erasure of “lithological memory” and the development of “soil memory” during one stage /spurt of evolution), on the other hand, is subject to various (including anthropogenic) factors of influence, theoretically, all types of nonlinear dynamic behaviors - chaos, multistability, amplitude decay, solitons. The change in soil condition over time within one stage of their multi-stage evolution is usually described by a logistic equation. Differentiating the state function S from time t allows us to get an idea of the rate dS/dt and acceleration d2S/dt2 of soil formation processes. The inflection points on the soil condition graph become the extreme points on the graphs of derivatives of soil formation. It is noted that dissipative processes prevail in the “first half”, and antidissipative processes prevail in the “second half” of each stage of evolution. The predominance of dissipative processes over antidissipative ones is not homogeneous at all: at first it occurs at the start of the acceleration of soil formation, and then — at the stage of decrease.

The dependence of soil bulk density on penetration resistance, moisture content, soil organic carbon content and particle size distribution was investigated for Retisols of the Educational and Experimental Soil and Ecological Center of Lomonosov Moscow State University “Chashnikovo”. Penetration resistance was measured with a penetrologger at six key sites with different land-use types, in areas in front of three soil profiles. Soil samples for bulk density were taken from the same profiles using 100 cm³ cutting rings. The samples were subsequently analyzed for moisture content, organic carbon (by the Tyurin method), and particle-size distribution using a laser diffraction analyzer. Within the study, 24 regression models for predicting soil bulk density were developed and analyzed. The quality of these models varied; the coefficients of determination (R²) ranged from 0.23 to 0.89 and the root mean square error (RMSE) from 0.07 to 0.18 g×cm^–3. Based on the modelling results, the greatest contribution to predicting bulk density was made by organic carbon content, depth and penetration resistance, in descending order. Adding specific particle-size fractions to the model is more informative than using the principal components of particle-size fractions as predictors. The use of specific particle-size fractions is more informative than using principal components as predictors. In many models, field soil moisture proved to be an insignificant predictor for bulk density. Given the labour-intensive nature of determining a full set of predictors, models with a reduced set of predictors were proposed: 1) depth and penetration resistance; 2) organic carbon content and penetration resistance; and 3) organic carbon content alone. The data from the first of these models are automatically collected during the use of the penetrometer, making it convenient for monitoring surveys. The method has important limitations relating to the particle size distribution of soils and how this is determined. For example, it is impossible to take a top-down measurement of penetration resistance with a penetrologger in the presence of large boulders in the soil, as the measuring tool hits them and cannot be pushed into the underlying horizons. The use of regression equations in which particle-size distribution is determined by a method other than laser diffraction is incorrect. The choice of which particle-size fraction to use as a predictor should be based on a correlation analysis for each territory in question.

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.

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 paper presents the results of a study of the impact of rail transport on the forest ecosystems of the Valdai National Park. Previously, comprehensive scientific studies of the impact of railways on specially protected natural areas were not conducted. The location of the park in an important transport corridor affects the ecological state of natural systems. Unlike most territories through which railway communication is carried out, the site chosen for research allows assessing the environmental impact of railway transport in the absence of other anthropogenic sources of impact. The gross content of heavy metals and metalloids in the soils of the section adjacent to the railway and the background territories of the park has been determined. Analysis of the gross content of heavy metals in soil samples taken in 5 m increments from the railway embankment showed an excess of the maximum permissible concentrations (MPC) of some elements at a distance of 30 meters from the track. The maximum permissible concentration is observed in manganese, nickel, copper, zinc, arsenic, cadmium and lead. The embankment has a high content of elements such as strontium, barium, copper, and iron. The calculation of quantitative indicators of soil contamination showed that a strong level of contamination is observed at the embankment and at a distance of 25 and 30 m from it. A correlation analysis was conducted, and a model for the distribution of heavy metals and metalloids was presented. An important result of the study was the identification of the role of natural plant communities in the migration and accumulation of pollutants. It was found that the gray alder, located 30 meters away from the embankment, acts as the first mechanical barrier that limits the spread of heavy metals. The second barrier is formed by the sour spruce, which grows 43 meters away from the railway track. These natural filters help to reduce the intensity of the migration of pollutants into the depths of the forest. Exceeding the permissible limits for manganese, nickel, copper, zinc, and cadmium in soils is associated with the wear and tear of railway transport facilities (wheels, rails, and wagons). Arsenic is a component of diesel particulate matter. The increased copper content is associated with railway lubrication, and barium and strontium indicate the use of carbonate crushed stone on railway embankments. The results obtained contribute to understanding the mechanisms of the spread of pollutants from linear transport facilities, are of practical importance for the development of environmental protection measures, and can be used to normalize the impact of rail transport within specially protected natural areas affected by railway.

The article presents a comparative analysis of the spatial structure of technogenic impacts on soil cover under conditions of localized (point-source) and diffuse (area-wide) pollution. The study focuses on the territories of Sverdlovsk and Tula regions, which are contrasting in terms of land use and the nature of anthropogenic transformation. The former is characterized by an industrial landscape dominated by stationary emission sources, while the latter represents an agro-industrial region with a developed background level of pollution formed by the combined effects of agricultural activity, dispersed emissions, and long-term radiological impacts. Based on data on heavy metal (Cu, Pb, Cd, Zn) concentrations in soils and the application of remote sensing (NDVI) and geoinformation analysis methods, a functional zoning approach is proposed. This approach allows for the differentiation of land areas by the intensity of technogenic pressure and the degree of ecological transformation. The methodological framework includes key concepts such as the environmentally permissible background (EPB), the anthropogenically modified background (AMB), and the point of no return (PNR), the latter being interpreted as a critical threshold beyond which ecosystem degradation becomes irreversible and bioproductivity steadily declines. The zoning model comprises sanitary protection zones (SPZ), ecological responsibility zones (ERZ), and post-contamination zones (PCZ), each of which possesses specific functional and regulatory attributes. The paper substantiates the need to move away from universal maximum permissible concentrations (MPCs) toward regionally adapted background-based benchmarks derived from empirical observations. The proposed methodology was tested across representative sites with varying degrees and types of anthropogenic influence and demonstrated high sensitivity to the interplay between physicochemical and landscape factors. The findings offer a more substantiated basis for the design of sanitary and environmental protection measures, refinement of soil quality standards, and formulation of sustainable land-use strategies. The developed approach can be applied in the practice of environmental and cadastral services, regional spatial planning, industrial environmental assessment, and soil and environmental monitoring systems at both regional and municipal levels.

The results of a vegetation experiment on the humus horizon of sod-podzolic sandy loam soil (Albic Retisol) are presented. Until 1990, sewage sludge was added to the soil, which resulted in the formation of complex polyelement pollution with heavy metals, and even after 30 years the soils remained contaminated.

During this period the phosphorus content decreased by 4 times, potassium by 1.5, and the organic carbon content by 1.6 times. The content of heavy metals also decreased significantly compared to the initial level: Cd by 5 times, Zn and Cu by 1.5 times, Pb by 1.4 times. Vegetation experiments using zeolite clinoptilolite, zeolite ZION and the humic preparation “Vibrostand” showed the possibility of reducing the content of heavy metals using ameliorants in Vicia sp. plants and, to a smaller extent, in Avena sp. A study of the effect of ameliorants on the content of heavy metals in plants grown on soils fertilized with sewage sludge 30 years ago showed that their application changes the content of heavy metals and their distribution within plant organs. Moreover, Vicia sp. plants accumulate significantly less heavy metals than Avena sp., which can be used on soils taking into account their pollution levels. The ameliorants used in the experiments reduce the content of Cd, Zn, Cu and Ni in Vicia sp. plants by 40–60%, but the standard content of heavy metals in plants could not be achieved with such a high level of soil pollution. For Avena sp. plants, the ameliorants were less effective.

The number of soil bacteria is an indicator of the condition and health of soils under chemical contamination. However, the native abundance of soil bacteria in the soils of different climatic zones varies significantly. Depending on the soil-forming factors, the number of bacteria in the soils of different climatic zones will vary. To assess changes in the number of soil bacteria, soil contamination of different climatic zones (semi-deserts, steppes and forests) with lead (Pb) in the following concentrations was modeled: 100, 1000 and 10,000 mg Pb×kg^–1 of soil. It was found that at a maximum concentration of 10,000 mg Pb×kg^–1 of soil, the number of soil bacteria in different types of soils was inhibited by 46–92% compared with the control. With an increase in Pb concentration, the number of soil bacteria decreased in semi-desert soils: from 1.61 billion×g^–1 (typical salt marsh) to 0.89 billion×g (chestnut and brown semi-desert soils); in steppe soils: from 4.50 billion×g^–1 (podzolic chernozem) to 0.80 billion×g^–1 (common chernozem); in forest soils: from 8.00 billion×g^–1 (dark gray forest soil) to 1.90 billion×g^–1 (sod-podzolic soil). The soils of the forest climate zone were found to be the most resistant to Pb pollution, while the soils of the steppe climate zone were the least resistant. Among semi—desert soils, the most sensitive are typical salt marshes, among steppe soils — podzolic chernozems, forest soils - sod-podzolic illuvial-ferruginous soils. A comparison of the number of soil bacteria in three climatic zones of Russia with lead contamination has been carried out. The results of the study can be used to indicate the ecological status and health of soils contaminated with heavy metals.

The concept of "soil health" has gained significant popularity in scientific literature as a key framework for ensuring ecosystem sustainability. However, the meaning of this term remains ambiguous, and universal assessment criteria are lacking. The aim of this article is to analyze contemporary definitions of "soil health" proposed by domestic and international soil scientists and to review methods for its evaluation. Emphasis is placed on indicators and monitoring systems that claim a degree of universality in diagnosing soil health. According to the European conceptual framework, the term "soil health" should reflect the broad influence of soil cover on ecosystems, including traditionally recognized aspects such as crop productivity, water and air quality regulation, climate regulation, biodiversity conservation, and the provision of social and cultural ecosystem services. In 2021, the European Union adopted a soil development strategy aimed at achieving healthy conditions for all EU soils by 2050. The term "soil health" is expected to be formalized with the adoption of the Soil Monitoring and Resilience Law, which will establish soil health standards. Researchers from Cornell University (USA) have proposed a similar methodology for comprehensive soil health assessment, termed CASH (Comprehensive Assessment of Soil Health). Both systems – CASH and the Soil Monitoring and Resilience Law – are examined in detail in the article. Additionally, the search for a universal soil health indicator continues; the article discusses metrics such as organic matter content, the soil organic carbon-to-clay ratio (SOC:Clay), and its alternatives (Observed/Typical SOC ratio, SOC/SOCexp). A literature review reveals that the rationale for introducing the term "soil health" remains questionable. In practice, "soil health" is almost universally interpreted as a combination of physical and chemical properties that potentially influence soil fertility. Moreover, practices aimed at restoring "soil health" primarily focus on maintaining agronomic soil properties. In this regard, the indicators and methods for assessing "soil health" differ little from those used to evaluate "soil quality". Russian studies tend to explore fundamental aspects of soil system resilience, emphasizing the biological origins and biodynamic essence of soil. Proposed assessment methods are also based on microbiological indicators: thermodynamic characterization of microbial systems, the heterotrophic parameter of soil health, the self-sufficiency parameter for biophilic elements, phytosanitary soil status indicators, and enzymatic activity. The reviewed indicators and monitoring systems demonstrate potential for comprehensive soil diagnostics. However, their universality is limited by variability in soil-climatic conditions and land-use types.

The review provides a brief description of ecotoxicodynamics as a section of environmental toxicology including the subject of research, theoretical underpinnings and relevant studies. It has been shown that the development of ecotoxicodynamic studies at the present stage associated with the assessment of environmental quality and risk, establishing a database for ecological regulation, analysis of the processes of degradation and self-restoration of natural ecosystems.Particular attention is paid to the analysis of achieved successes in the study of the action of ecotoxicants on the example of their new types (nanoparticles, microplastics, harmaceuticals, food additives). The potential for them to exhibit toxic effects from genetic to ecosystem level including with real existing content has been demonstrated. The effects in organisms manifest as geno- and cytotoxicity and are reflected in violations of the reproductive, immune, enzymatic and digestive systems, behavioral reactions, decrease the rate of growth and development of organisms, the rate of photosynthesis, etc. In ecosystems the consequences of these effects may be а decline in the number and extinction of sensitive species, negative changes in interspecies relationships, loss of biodiversity and productivity of the biocenosis. Gaps in the study of new ecotoxicants are shown, to eliminate them promising research directions have been proposed in particular: investigations оn sublethal effects under real ecosystem loads, assessment of the possibility of developing chronic and delayed effects, detection of the influence of ecotoxicant properties and environmental factors оn toxic effects as well as consideration of combined effects of several ecotoxicants and products of their transformation. The problematic aspects in the study of ecotoxicants were noted by authors of the reviewed research papers. They are (1) the differences in the "scenario" of experiments among different authors, that make comparative assessment difficult to identify general patterns of possible ecotoxicant action in the environment, (2) application model experiments with standard media, that do not reflect real natural conditions and reduce the practical significance of the results obtained.

A laboratory experiment was carried out to investigate the sorption behavior of 2.4-D onto two types of bentonite material: Na-Ca bentonite and organically modified bentonite (HDTMA-Br) using hexadecyltrimethylammonium bromide. The amount of HDTMA-Br was equivalent to the cation exchange capacity of the dominant mineral, montmorillonite, in the bentonites. The results showed that the organically modified bentonite absorbed 4.5 times more 2.4-D compared to the unmodified Na-Ca bentonite, indicating a significantly stronger sorption affinity for the organic cation. This finding suggests that organically modified bentonites may be more effective for the removal of 2.4-D from contaminated soil or water. In the range of pH values between 4 and 6, the sorption sites on the hydrophobic surface of organobentonite were found to have a relatively uniform energy for 2.4-d molecules (Freundlich constant n ≈ 0.8). Hydrophobic interactions were the dominant mechanism for the uptake of 2.4-D at these pH values. The possibility of using HDTMA-bentonite to reduce the mobility of 2.4-D in soils and landscapes, or to create new formulations, should be considered only after a thorough evaluation of the toxic effects of the organoclay on nontarget organisms.

Currently, the physiological and biochemical role of certain groups of phenols that have high biological activity remains poorly understood. Thus, the functions of hydroxycinnamic acids, related to phenylpropanoids, and, in particular, caffeic acid (CA), remain unclear.

The purpose of this work was to study the effect of different concentrations of caffeic acid on barley productivity, both under normal plant development conditions and in the presence of salt stress.

In a series of laboratory experiments using different test cultures and in a growing season on spring barley plants Hordeum vulgare L., the effect of CA was studied. The activity of different concentrations of caffeic acid was determined using several methodological approaches to phytotesting: the express method in Petri dishes; in plastic flat tablets using the applicate method; in conditions of growing plants in aqueous solutions. The vegetation experiment was carried out on gray forest medium-loamy soil with an organic matter content of 3.8%, a slightly acidic reaction of the soil solution (pH_KCl 5.9). NaCl solution (7.5 g×l^–1) was added to the 2–3 leaf phase. Plants were treated with CA foliarly once during the tillering phase. Three concentrations of CA were used in the experiment, based on the results of preliminary laboratory experiments: 100 µM, 50 µM, 10 µM. At the beginning of booting, the barley plants were harvested and soil samples were taken. Potassium, sodium and total nitrogen content were determined in dry plant mass. The flag leaf of plants was used to determine the content of chlorophyll and carotenoids.

According to the results of phytotesting, it was established that for monocotyledonous and dicotyledonous crops the greatest activity is manifested in variants with the lowest concentrations of CA (10 and 25 μM), while higher concentrations of CA (50 and 100 μM) significantly reduce all test indicators. Based on the results of the growing season, it was established that CA does not have a reliable stimulating effect. Under conditions of sodium chloride salinity with the use of a high concentration of CA (100 μM), a slight increase in the potassium content in the soil occurs. The sodium content in the soil decreased with the use of CA. The total plant weight per vessel decreased significantly from 1.25g/vessel to 0.25g/vessel. Without the use of NaCl, CA treatment was not accompanied by significant changes in barley weight. The content of chlorophyll (a and b) in the control variant (1.83 mg×g^–1) was significantly lower compared to their content in the leaves of plants that were treated with CA (4.03 mg×g^–1 — 10 µM and 3.14 mg×g^–1 — 100 µM). Against the background of NaCl, the content of total chlorophyll decreased to 0.24 mg/g, and when plants were treated with CA it increased from 1.26 mg×g^–1 at low concentration (10 µM) and to 2.14 mg×g^–1 at high concentration (100 µM). The use of CA at a concentration of 100 µM was accompanied by an increase in carotenoid content from 0.22 mg×g^–1 to 0.61 and, against the background of salinity, from 0.16 to 0.38 mg×g^–1. Thus, the use of CA for treating plants during the growing season under salinity conditions affects changes in physiological processes, which contributes to their adaptation.

The response of biological activity and the content of labile forms of biogenic elements in peats of different genesis to variation in their moisture content was studied under laboratory conditions. Samples of peat soils of the northern and southern taiga (Tyumen and Moscow regions) were used in this work. A series of manipulation experiments were conducted in which the dynamics of such indicators as basal respiration (BR), microbial biomass carbon, labile carbon and nitrogen content were estimated for different peat types at different moisture levels. The effect of the experiment duration and type on the dynamics of peat properties was also assessed. It was found that all the studied peat samples are characterized by a wide range of moisture content, at which the maximum of biological activity is observed. In general, it is in the range from 20–30% to 80–90% of water–holding capacity (WHC). In this range, no significant relationship is observed between moisture content and BR. In most experiments, a reliable decrease in biological activity was observed only in the "extreme" humidity ranges - less than 20% and more than 90% WHC. It is shown that the nature of the response to moistening is individual, determined by the properties of the sample and depends little on the type of sample preparation. In experiments and model calculations, it is proposed to use the obtained sensitivity coefficient to moisture — W₂₀, which is 1.0‒1.2 in the range of 40‒80% WHC for peat samples of different genesis. Long-term variants of incubation experiments showed a more pronounced response to overmoistening and a reliable decrease in biological activity at high humidity values (more than 80% WHC). This may indicate their better applicability for solving problems of modeling the behavior of ecosystems in the event of a change in the hydrological situation.

The article presents the results of the study of the dynamics of changes in agrochemical parameters of soils and soil cover structure changes as a result of hydrotechnical melioration, using the example of the experimental site of the agricultural organization “Bobrik”. It was established that over a 50-year period, the reaction of the soil changed from slightly acidic pH_KCl 5.5–6.0 (68.8% of the area of the farm under study (530 ha)) to neutral (pH_KCl 7.0–7.5) and slightly alkaline (рН_KCl 7.5–8.0), while the optimum for sandy soils is 5.5–5.8 рН_KCl. Optimum values were reached for potassium content in 2022, after many years of chemical treatment of the site as a whole, and 48.5% of the territory for phosphorus did not reach the range of optimal values. Analysis of the structure of the soil cover showed that the number of soil contours increased from 58 to 172 during economic use, and the average area of the ESA decreased from 15.93 ha to 6.34 ha. An increase in the heterogeneity of the soil cover leads to an even more active redistribution of substances, including excessive accumulation of fertilizers. Based on the calculated morphometric coefficients of the soil cover structure, it was established that only 146 ha (13.9% of the site area) can be effectively used as arable land for the restoration and rational use of the studied agrocenosis. Taking into account the agrochemical potential of lands recommended for removal from agricultural production due to very high heterogeneity of the soil cover, their area is reduced from 72.5 ha to 23.2 ha due to the inclusion of elementary plots with agrochemical parameters sufficient for meadow use.

The historical and modern concepts of fallow lands (abandoned cropland), the causes of their occurrence and some features of their functioning are considered. The main stages of the development of abandoned cropland are highlighted from the perspective of a consistent change of vegetation in agrophytocenoses that arise after the cessation of soil cultivation. The literature data and existing approaches to assessing the land area of arable land withdrawn from agricultural circulation are analyzed. The prospects of using abandoned fallow lands both in the agricultural sector of agricultural production and in the broader ecosystem plan are considered. Attention is drawn to the fact that deposits of different ages are, in fact, chronological sequences of various dynamic biogeocenoses with actively transforming plant and soil components, which make it possible to assess, among other things, the rate of soil formation and degradation processes.

The adsorption properties of dispersed systems are determined by their surface energy, therefore the indicators of hygroscopy (adsorbed water content) and dispersity (specific surface area of the solid phase) of soils and sediments are in close mutual correlation. This well-known empirical fact received a new fundamental interpretation based on the theory of disjoining water pressure according to Deryagin in the form of a thermodynamic equation connecting the specific surface area, hygroscopic water content of soil samples and the relative humidity of the air in the laboratory room. The theoretical equation allowed us to substantiate the methodology for quantifying the hydrophilic specific surface area of soil samples based on widespread data on their hygroscopy. A comparison of the new method with the standard BET-analysis of the specific surface area, as well as with the previously proposed physically based method for its determining by the slope of thermodynamic water retention curves, showed their statistically reliable agreement in a wide range of estimated specific surface area values from 5 to 340 m²×g^-1 for soil samples of different genesis and texture.

The article provides data on a comparative analysis of the features of vegetation restoration in areas of oligotrophic bogs with a high degree of oil product pollution, located on the territory of an oil field in the Middle Ob region, reclaimed according to standard schemes, widely used in the 2000s, and by cutting off oil-contaminated soil. The total projective vegetation cover (TPVC) of all reclaimed areas mostly reaches standard values (above 30%). The TPVC in areas without cutting is slightly higher than in areas with cutting due to the difference in recovery time in favor of the former. At the same time, the average number of all recorded species in areas with cutting is slightly higher, and they include some oligotrophic vascular plants (heather shrubs, Drosera rotundifolia, Eriophorum vaginatum), which spread much less frequently in areas without cutting. The projective cover of the herb-shrub layer is higher in areas without cutting. The content of oil products in the surface layer of 0‒20 cm in areas with cutting is generally lower compared to areas reclaimed by traditional methods. However, even high concentrations (more than 250 g×kg^-1) do not have a significant negative effect on the total projective cover of the grass/herb-shrub layer, while its minimum values are primarily associated with a lack of moisture on high microrelief elements. Similarly, high concentrations of hydrocarbons do not serve as an obstacle to the development of moss cover dominated by sphagnum mosses in areas of cut-off hollows. At the same time, polytrichous and brown mosses were much more sensitive to oil pollution in the form of bitumen crust, and thus avoided areas without cutting.

The effectiveness of remediators in detoxification of soils contaminated with heavy metals was studied in a lab experiment. The objects of the study were the soils of the southern tundra, functioning under conditions of anthropogenic impact: Haplic Gleysols (Gelic) and Histic Fluvisols (Oxyaquic). The chemical ability of remediants to bind metals (Ni and Cu), transferring them to a sedentary state in comparison with the reference variants (without any addition of remediants), was evaluated. In experiments, remediants were used in three doses (D1, D2, D3): shungite; diatomite, glauconite and bentonite. To assess the immobilization of Ni and Cu in soils, acid-soluble (CR) forms (extraction of 1 n. HNO₃), mobile forms (ammonium acetate buffer solution with pH 4.8), water-soluble forms of Ni and Cu (1:20 aqueous extract) were determined by inductively coupled plasma mass spectrometry. The effectiveness of soil detoxification during the application of remediants was evaluated by the phytotoxic effect in an express phytoassay with standardized tests (Brassica rapa CrGC and Avena sativa) represented by higher plants. A decrease in the proportion of mobile forms of Ni and Cu by 50% or more in Haplic Gleysols (Gelic) was revealed with the addition of any dose of ameliorants. The greatest effect of reducing mobility was exerted by shungite and diatomite at a dose of D1 — up to 15% Ni and Cu for Histic Fluvisols (Oxyaquic) soil. The use of the selected remediants in the indicated amounts did not reveal a phytotoxic effect on the tests in the experiment.

We studied morphological properties, pH, organic carbon content, and specific activity of ¹³⁷Cs and natural radionuclides (⁴⁰K, ²²⁶Ra, ²³²Th) in the upper horizons of soils in deactivated and slightly damaged areas of the city. The studies were carried out in the urban ecosystems of the city of Elektrostal (Moscow region) in 2019, i.e. 6 years after local precipitation of ¹³⁷Cs due to a radiation incident. Morphological features of the upper horizons of urban soils were: brownish-gray color, light-loamy composition, small-lumpy and lumpy structure, inclusions of construction and household waste. In the upper horizons of urbiquasizems and urban soils, a low carbon content (less than 1%) with high coefficients of variation - were detected. In the studied urban soils, a wide range of water pH values was noted: from acidic (4,6–5,5) to highly alkaline (>8,0) reaction. Correlation analysis showed that in the upper horizons of UR, the content of organic carbon was reduced and alkalinization of the soil environment was observed. The accumulative type of distribution of ¹³⁷Cs was recorded for soil profiles of polluted urban ecosystems in which decontamination measures were not carried out. The profiles of urban soils that were subjected to decontamination revealed low values of the specific activity of ¹³⁷Cs in surface bulk layers and maxima in buried contaminated horizons. In the bulk horizons of UR, which include a large amount of crushed stone, there is an increase in the specific activity of ²²⁶Ra. Some technogenic horizons UR and TCH, consisting mainly of quartz sand, are characterized by very low values of specific activities ²²⁶Ra and ⁴⁰K. Correlations of chemical and radiation indicators in the profiles of urban soils reflect the different composition and properties of upper horizons formed as a result of excavation and decontamination work.

As part of the study of the ecological state of soils and vegetation in the zone of impact of the Sredneuralsky Copper Smelter (SUMZ), the following tasks were solved: the content of heavy metals in the soils of the test sites laid within the zone of impact of the SUMZ was determined; macrokinetic patterns of seasonal dynamics of the normalized relative vegetation index (NDVI) at the test sites in the zone of impact of the SUMZ were revealed; macrokinetic patterns of vegetation response in the form of NDVI, calculated according to MODIS and Landsat 8 data, to soil pollution by a complex of heavy metals in the zone of impact of the SUMZ were revealed; soil quality was ranked according to the patterns of vegetation response in the form of NDVI to soil pollution by a complex of heavy metals within the boundaries of the natural protection zone (NZZ) of the SUMZ according to 2023.

The intra-seasonal dynamics of photosynthetically active biomass in the form of NDVI was modeled using a theoretical growth equation based on MODIS satellite data. The seasonal maximum of the vegetation index at the trial sites in 2012 fell on the 25‒28 week. In 2023, it occurred on the 27‒33 week, depending on the location of the sampling point. The rate of maximum achievement is characterized by weak intra-seasonal and interannual variation.

The patterns of changes in the concentration of photosynthetically active biomass in the form of maximum NDVI for the 2023 season in response to the gross content of a complex of heavy metals (Cu, Pb, Cd and Zn) in the soil of the test sites were modeled using the theoretical equation of dose dependence. The maximum permissible level of the heavy metal complex in the soil in the form of a geometric mean, which does not cause a decrease in the values of the vegetation index calculated according to the data of the MODIS and Landsat 8 satellites, was 101 and 106 mg×kg^-1, respectively.

The analysis of histograms of the distribution of NDVI values within the NZZ was carried out, which showed how the true frequencies of occurrence of the values of the vegetation index correspond to the empirical boundary of the NZZ associated with the maximum dose dependence point identified by the study of the 2012. The nature of the distribution of true NDVI values for the NZZ exclusively fully supports the used zoning theory based on the analysis of dose dependence. The modern boundaries of the SUMZ natural protection zone are 4‒7 km away from the center of the sanitary protection zone.

Ratuioning of the content of hazardous substances in soil as an object of environmental protection in the Russian Federation is provided by a set of normative acts establishing the principles of assessment, approaches to the use of soils of varying degrees of anthropogenic transformation, the level of their pollution, at which the responsibility of the land user for violation of legislation on soil protection occurs. The analysis of normative acts shows that the most stringent pollution regulation system has been established in Russia, which is based on determining the compliance of the content of chemical elements and compounds in soils with sanitary and hygienic standards in the territories of settlements and agricultural lands. On other lands, as a standard, the excess of which leads to the onset of economic responsibility for pollution, the value of the concentration of the pollutant in the adjacent territory of a similar purpose and type of use, which is not adversely affected by a specific type of violation, is applied. At the same time, chemical elements and compounds are considered as pollutants, regardless of their origin, degree of danger and biological significance. The application of this approach within the framework of law enforcement practice creates significant problems in establishing the fact of negative impact, calculating the amount of damage from pollution, and developing measures for soil remediation. Thus, the current regulations consider as pollutants substances of natural origin, including those that ensure soil fertility and are applied with mineral and organic fertilizers. The use of the background level of substances as the maximum permissible value does not take into account the natural variability of elements and compounds in soils, as well as the errors of their chemical analysis. The excessive rigidity of the applicable standards is the reason for the increased costs of soil remediation measures.

The way out of this situation is to revise the rationing system, taking into account the biological significance of elements and compounds, and the need to introduce a multi-level system of soil quality indicators. There is a need to improve the conceptual framework as part of regulatory documents on soil protection.

The article discusses one of the ways to assess the condition of soil cover to improve the efficiency of land management using the example of the Volozhin region of the Republic of Belarus. A comprehensive assessment of the agrochemical and natural potential of the soil is proposed by means of typing the soil cover depending on agrochemical indicators (pH_KCl, humus content, mobile compounds of phosphorus and potassium) and a quality score reflecting the natural state of the soil. Using geostatistical methods, the values of agrochemical indicators were interpolated from elementary areas into areas of soil varieties of agricultural lands and classified according to the degree of content of agrochemical elements that made up the agrochemical potential (AP). After crossing the AP with the bonitet score, 9 groups of soils were identified according to soil-agrochemical potential (SAP), of which the largest share (58,2 %) is occupied by soils with average potential (61,950 ha). Based on the results of a spatial assessment of the PAP, it was determined that sod-podzolic and sod-podzolic swampy soils developing on light loams and cohesive sandy loams have the greatest potential. It was also revealed that areas with low PAP gravitate towards the most dissected areas of the terrain with sandy and cohesive sandy soils. Based on the typification carried out, the main types of preferred land use in the Volozhin region were determined: more than half of the agricultural land can be used for intensive agricultural use for arable land (52,1 %) and meadows (12,5 %), traditional land use is possible for 29,3 % territories and only 6,2 % of lands require the use of soil protection farming systems, primarily focused on erosion-hazardous areas of the area.

For landscape conditions in the upper reaches of the river Klyazma, Solnechnogorsk district, Moscow region, the height and reserves of snow cover were investigated, and the chemical composition of the snow was determined. The basis for considering the component composition of snow cover was the geochemical taxonomy of chemical elements based on the characteristics of water migration and abundance.

Data from 23 snow sampling points were interpolated in SAGA GIS using the inverse distance weighting (IDW) method. On this basis, zones differing in the chemical composition of snow are identified. One of the zones is confined to the M-10 Moscow-St. Petersburg highway, while the second borders on populated areas. The area close to the highway is characterized by increased levels of calcium, sodium, aluminum, and chloride ions in the snow cover. The second zone, bordering populated areas, is characterized by a high content of calcium, copper, and manganese in the snow. For the third zone, low concentrations of components in the snow were observed, which are characteristic of a superaquatic landscape due to the distance from sources of pollution.

The studied composition of snow waters belongs to the bicarbonate-sodium-calcium-chloride class. It has been shown that the height and reserves of snow cover are partially controlled by two factors: the type of elementary landscape and the type of ecosystem. Against this background, the spatial distribution of concentrations of elements and anions in snow is predominantly controlled by the anthropogenic factor.

The aim of the work was to assess the contribution of the following components – biomass and mortmass of tree stands, undergrowth, living ground cover, and forest litter — to the total organic matter’s pool of plant community. The object of the study was a territory of coniferous-deciduous forest located in Solnechnogorsk City District of the Moscow region, in which five permanent sample trial plots of 50×50 m were allocated. The greatest contribution to the total organic matter mass of studied plant communities was made by forest stand perennial parts (up to 87%) and forest stand mortmass (up to 14%), and phytomass of deciduous trees in stand containing 32 to 98%, which was connected with incompleteness of forest restoration succession process. The contribution of forest litter was no more than 3%; litter deposit was low (0,18–1,21 kg×m^-2), which is not typical for spruce forests, as is the fact that all litter is of the destructive type. Living ground cover in terms of floristic composition and ecological-coenotic structure was typical for the subzone of coniferous-deciduous forests; its contribution to the overall productivity of forest biogeocenosis was insignificant. The spatial intrabiogeocenotic structure of litter reserves and living ground cover biomass distribution was disturbed compared to typical spruce forests due to the high proportion of deciduous species in the forest stand. Deciduous species inclusion in the tree tier, typical of the final stage of formation of a secondary coniferous forest during succession, caused a slight increase in the intensity of the biological cycle, which was indicated in this case by a decrease in the supply of litter and a simplification of their structure. Since the biomass and mortmass of tree stand make the greatest contribution to the sequestration of carbon by forest biogeocenoses, it is these components that require the most detailed assessment during monitoring observations, the purpose of which is to assess the carbon reserves of terrestrial ecosystems.

The influence of the discharge of spent aircraft deicing fluid (ADF), utilized in civil aviation, on the chemical composition of the eluate of sod-podzolic soil was being studied in a column experiment. It was determined that Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, and Zn are released into the environment together with the ADF. It is also shown that the ADF leads to changes in the indicators of the composition of lysimetric waters such as СOD, pH, Eh, electrical conductivity, and heavy metal content. As a result of the ADF discharge, several elements, including Fe and Mn, become more mobile and migrate to the liquid phase, while others are fixed in the soil, resulting in the redistribution of elements in the soil profile.

Changes in the physical properties of podzolic soils were analysed three years after a cutting of coniferous-deciduous plantings in the territory of the middle taiga of the Komi Republic with three‒ and ten‒fold forwarder passes, as well as after leveling deep ruts formed after ten passes. The influence of different number of passes on soil density, filtration coefficient, penetration resistance is shown. An assumption about various mechanisms of soil change has been made: three forwarder passes lead to compression, ten — to compression and turbation, which was confirmed by indications of soil density and hardness. It was revealed that compression leads to an increase in density by 0.15 g×cm^‒3 and penetration resistance by 25%. Meanwhile, filtration rate did not change. Ten passes lead to turbation, which levels the possible compaction due to an introduction of forest litter into the upper mineral soil horizons. Moreover, hardness values decreased by 2‒3 times and water permeability decreased from 70 to 1 cm×day^‒1. It was revealed that leveling deep ruts causes a noticeable decrease in soil density after three years, including in comparison with the undisturbed soil. Furthermore, filtration rate increases several times. Penetration resistance is also increased. An estimation of the water retention curve approximation parameters by the van Genuchten equation made it possible to identify changes in soil of ruts compared to the a mechanically undisturbed site. A decrease in the range of mobile moisture was noted as a result of compaction after heavy equipment usage, leading to moisture stagnation in ruts.

The high water retention and water capacity functions of detritus determine its potential hydrological significance in the formation of the water regime of soils and phytoproductivity of forest landscapes. Using computer modeling of water exchange in the “soil-plant-atmosphere” HYDRUS-1D system, we preliminary studied the hydrological func- tion of detritus for water retention of precipitation and root water consumption at different amounts and variants of the arrangement of detritus layers in the soil profile. The soil structures designed on the basis of this information for sustainable afforestation with increased carbon sequestration demonstrated in field experiments with water balance monitoring high efficiency in optimizing the water retention capacity of the soil and roots water consumption of the test crop (Glauca spruce) with a 2-3-fold reduction in unproductive water losses and a 1.5–2-fold increase in the current plant growth relative to untreated control. The physical mechanism of the detritus hydrological function is the formation of capillary barriers blocking evaporation and capillary resorption of soil water due to due to surface accumulation (forest litter) or placement in layers inside the soil (peat layers in constructosems).

Milestones in the study of oil-contaminated soils at the Faculty of Soil Science for 50 years of its foundation are dis- cussed from the prospects for the development of environmental regulation and new technologies of soil reclamation. The development of a methodological framework for the determination of oil and petroleum hydrocarbons in soils, studies of soil properties, the chemistry of oil and its components in soil and adjacent media are shown. The devel- opment of legislation on the rationing of petroleum hydrocarbons in soils is given, including the important role of the staff of Faculty of Soil Science of Moscow State University in the work out of a number of regional standards for the permissible residual content of petroleum hydrocarbons in soils is noted. The approaches to ecological rationing of oil and petroleum hydrocarbons in soils are proposed, in the aspects of natural climatic zones and the type of landuse. The importance of improving the regulatory and methodological framework and continuing work in this direction is emphasized. The necessity of research at developing technologies for reclamation of oil-contaminated lands and special use of oil-contaminated waste is indicated.

The article summarizes the results of recent research by the staff of Soil Biology Department Faculty of Soil Science of Lomonosov Moscow State University in the field of assessing the genetic potential of microbial communities of soils and their application in the development of fundamental soil and environmental technologies. Promising areas of further work related to the use of the microbial potential of soils for the purpose of bioremediation territories from ecotoxicants, the development of technologies for self-purification of soils based on the stimulation of natural communities of microorganisms, as well as the use of microbial cultures for biodegradation of petroleum products, pesticides and synthetic polymers. Another important direction is related to the development of scientific basis for the indication of biological objects in the environment and space objects. Within the framework of this direction, genomic analysis of uncultivated microorganisms from the Arctic, Antarctic and other extreme habitats is carried out, and the knowledge gained apply as a model of alien life. Another relevant direction for the Department of Soil Biology is the development of agrobiotechnologies based on the management of the natural soil microbiome, the creation of microbial preparations-stimulators of plant growth and development, microbiological ways to increase the proportion of biological nitrogen in plant nutrition, application of microbial plant endosymbionts and bioin- secticides. An equally important aspect is the search of producers of biologically active substances, such as phyto- hormones, antibiotics, enzymes, probiotics, hydrolytics of natural and artificial polymers. The considered areas of research in the field of soil biology are important for improving land management, environmental protection and the development of environmental technologies.

The article deals with issues related to the development of radioecology as an independent scientific discipline. The achievements of the past years, the studies that are currently being carried out, as well as promising areas of development in this area are analyzed. A corrected periodization of the stages of development of radioecology is proposed, taking into account the experience accumulated to date in the field of this discipline. At the initial stage (1895–1929:), empirical material was collected; at the first stage (1930–1960), the theoretical foundation was laid and radioecology was formed as an independent discipline; at the second stage (1961–1990), intensive development of radioecology was noted, and at the third stage (1991–2010) — progressive development of radioecology; the forth modern stage of radioecology development falls at the beginning of the twentieth century (2011 — present). For each stage the main scientific achievements and evolution of ideas in the field of radioecology are considered. It is postulated that at present the development of this discipline is associated with the further improvement of world nuclear technologies, the elimination of the consequences of a number of radiation incidents (the accident at the Fukushima nuclear power plant, 2011), the revision of the concept of radiation protection of the environment and a number of other provisions. Particular attention is paid to forest radioecology, one of the most important main directions of this science.

Paleopedology is a booming scientific discipline that studies the soils of the past geological epochs in order to assess the paleoenvironmental evolution. The scope of paleosol studies embraces not only soils themselves, but also the products of their involvement in biogeosphere cycles. This ensures the planetary role of pedogenesis, which includes the transformation of the upper layers of the lithosphere including the increase in fine earth, new minerals, residual or accumulative concentration of elements. In the geological history of the Earth, pedogenesis is realized within the framework of exogenesis, which includes weathering, soil formation, sedimentation, diagenesis, and geochemical migration. The pedolithosphere records the critical points in the landscape evolution of the Earth from the very onset of the geological record, including the oxygenation of the atmosphere, the emergence of the higher plants and herbaceous biomes, the dynamics of interglacial-glacial cycles, etc. Paleosols are the base for paleogeographic recon- structions and predictive models of the future climate change. Paleopedology expands the horizons of soil science within the system of biogeosphere sciences and determines the development of new scientific disciplines — bacterial paleontology, paleogeochemistry, biogeomorphology, astropedology, geoarchaeology, ecological paleopedology, soil paleocryogenesis and the cryobiosphere studies. The historical dimension granted by paleopedology makes pedology a mature historical science.

For the purposes of ecological monitoring, the features of living ground cover and forest floor in spruce stands within Moscow urban territory were studied. Using ecological scales by Nitsenko, Ramensky, Ellenberg and Landolt, let to consider, that ruderalization of living overground cover is a result of recreation. Independently of spruce forest type, the absence of undergrowth results in increasing light penetrating and increasing species quantity. Variety of ecological spaces is a result of moderate trampling, which is mostly expressed in between-crown spaces. Hight trophy index by L.G. Ramensky is a result of increased weediness of overground cover. It is shown, that living overground cover characterizes the variety of tree layer and the level of anthropogenic impact on phytocenosis.

The forest floor in urban spruce stands is sensitive to changes in functioning conditions and can be used for ecological monitoring. Availability of forest floor studying and simplicity of parameter estimation allows getting information about organic matter accumulation in express-regime under various degrees of anthropogenic impact on urban ecosystems.

Within the system of trunk, crown and open space, the simplification of litter structure and decreasing organic matter total deposit are observed — this can be considered an invariant process.

Maximal uniformity of coverless spaces litter, composed by needles and branches, results from absence of living overground cover, in combination with low recreation in these spaces. This fact let to conclude, that coverless spaces are able to be used as most important objects for comparing spruce ecosystems with different overground cover. Two groups of indexes, characterizing structure-functional litter organization, are proposed. Indexes, characterizing structural litter organization, include the total deposit of litter and L horizon deposit. Indexes, characterizing functional litter features, include deposit and proportion of detritus as well as the same for easy-decomposed components, ratio of thickness (deposit) of L horizon and F horizon. The peculiarities of long-term spatial functioning are characterized by litter typology in the system trunk-crown-open space.

Spatial and temporal variability of the vegetation index were investigated in the vicinity of the anthropogenic source of heavy metals. The analysis of the special points of the theoretical equation of the dependence of the concentration of photosynthetically active biomass on the resulting concentration of pollutants in the soil revealed the maximum permissible concentration of heavy metals in the soil. The results of its determination in the northern forest-steppe under the current level of anthropogenic pressure, according to MODIS materials, amounted to 12,3, according to Sentinel-2 — 12,5 mg/kg, respectively. A method for generalizing the macrokinetic patterns of the response of the living organisms to anthropogenic impact is proposed. The results of the environmental risk assessment showed that the probability of exceeding the threshold concentration is 74%.

Based on the five-level quality scale and the indicator of soil state, the quality of soils and vegetation cover was ranked. The areas of the same resistance of soils and vegetation to the action of pollutants in the plant impact zone were mapped. Territories near the plant mostly correspond to the I and II categories of soil quality. The natural protection zone of the enterprise is allocated, and background territories are defined.

We studied the soils and vegetation cover of tombolo – bridges between the mainland and small islands on the coasts of the White and Baltic Seas. Tombolo are characterized by complex dynamics of sedimentation that determines a high level of heterogeneity of soils and associated vegetation cover. At the Kolezhma plot on the White Sea coast, ground- and surface-gley marsh soils are formed. Vegetation corresponds to marsh meadows of the lower and middle levels, and varies depending on salinity, acidity level and soil texture. At the Gakkovo plot on the Baltic Sea coast, soils are characterized by greater uniformity; in general, they have a sandy texture. The influence of the Baltic Sea on the soil and vegetation cover is significantly lower than that of the White Sea due to the weakly pronounced tidal dynamics of the Baltic Sea.

The article discusses the processes of transition to the aqueous phase and uptake from it by plants of stable (Cd) and radioactive (¹⁰⁹Cd) isotopes. Regularities of the distribution of Cd/¹⁰⁹Cd between different forms of their chemical compounds in the soil were revealed by means of sequental extraction procedure (SEP) according to the Tessier-Förstner method. It was shown that content of labile and conditionally labile forms of compounds (fraction F1-F3) of stable Cd was 1,2–1,8 times less than that of radioactive ¹⁰⁹Cd and, conversely, 2,4–5,3 times more fixed conservative forms of metal compounds (fraction F4-F6). The Cd concentration, ¹⁰⁹Cd activity concentration, distribution and concentration coefficients of natural Cd and ¹⁰⁹Cd radionuclide, accumulation and removal of metal by plants were evaluated. Values of enrichment coefficients of natural (stable) Cd contained in sequentially extracted chemical fractions by ¹⁰⁹Cd radioisotope were determined, the value of stock of labile cadmium compounds in studied soil was calculated. Based on the results of solid-state ¹³C NMR spectrometry, the qualitative composition of high-molecular organic compounds of the soil solution was determined and their ability to specifically sorb heavy metal cations was assessed.

An analysis of the isotopic composition of vegetation and organic matter of permafrost burozems in the south of the Vitim Plateau was carried out. The soil profile is characterized by a pronounced uneven distribution of carbon. The main part of carbon reserves is concentrated in the humus-accumulative horizon, down the profile — much lower.

Vegetation on burozems belongs to the C-3 type of photosynthesis. In legumes, forbs, and semi-shrubs, the aboveground parts are somewhat depleted in the ¹³C isotope compared to the underground ones. In trees, the content of 13C in branches, needles, and leaves differs slightly.

The isotope composition of carbon in the upper horizons of soils depends on the type of phytocenosis and has close values to δ¹³C in dominant plants. With depth, carbon isotope fractionation shows a clear vertical differentiation along the soil profile.

The carbon of humic acids in soils from the humus-accumulative horizon and from cryogenic fissures slightly differs in isotope composition. The composition of stable carbon isotopes of humic acids in the soil profile remains approximately at the same level. These data indicate the similarity of the processes of humic acids formation in the upper soil layers and in humus pockets.

Natural ¹³C abundance of different organic matter (OM) pools of Haplic Chernozem (Streleskaya steppe plot of the Central Chernozemic State Biospheric Reserve) isolated by granulo-densitometric fractionation was studied. Natural variations of the ¹³C/¹²C ratio (δ¹³C) allowed to confirm the sequence of OM decomposition in soils, which follows a continuum from fresh and partially decomposed organic materials in the discrete OM (Free and Occluded) to significantly/completely processed in the mineral-associated OM (Clay and Res). This is reflected in the increase of the δ¹³C value during passing from discrete to mineral–associated OM. All studied OM pools are subjected to microbial processing, but in different extent. Free OM, despite the fact that it consists of well-recognized plant material, is not always the most fresht and most undecomposed organic material. The «lighter» isotope signature of occluded OM as compared to free OM, despite its obvious higher degree of microbial processing, may be a consequence of its physical protection in microaggregates (unstable under the sonication) within the soil structural units. The most microbial processed mineral-associated organic material (Clay and Residue fractions) is characterized by the «heaviest» isotopic signature. The isotopic composition of carbon in the whole soil is mainly determined by the Residue fraction due to its quantitatively domination in the bulk soil.

The conceptual scheme allows to quantify the carbon (C) fluxes of in the OM pool / soil system. It was revealed that the main C fluxes in the OM pools go from the Free OM to the Residue fraction through unstable under the sonication microaggregates. The most probable C flows into the whole soil — unstable under the sonication microaggregates, as well as the Residue fraction, which are characterized by the lowest Δ¹³C values (difference between Δ¹³C of «sourse» and «product»).

The total content of lead, the content of its acid-soluble and mobile forms of compounds in sod-carbonate soils of the impact zone of the Cherepovets Steel Mill (Vologda region) were studied. The isotopic composition of lead of its specified forms of compounds has been determined. It is shown that lead, being a part of the gas and dust emissions of the enterprise, is detected in increased quantities up to 6–10 km in the north direction studied by us from the source of pollution. The penetration of technogenic lead compounds down the soil profile up to horizon B is observed. The isotopic ratios of lead ²⁰⁶Pb/²⁰⁷Pb, ²⁰⁸Pb/²⁰⁶Pb and ²⁰⁸Pb/²⁰⁷Pb studied by us reveal clear dependencies on the lead content in soils. For all isotopic ratios in the series «total lead < acid-soluble lead < mobile lead», the contribution of technogenic lead compounds to its isotopic composition increases, since in the same series there is an increase in the proportion of technogenic lead compounds from its total amount. Extrapolation of the dependence of the ratio ²⁰⁶Pb/²⁰⁷Pb on the lead content in the low content area gives the value of this ratio in the range of 1,19–1,25, which corresponds to the isotopic composition of the total lead of the background soils of the European part of Russia. In high polluted soils near Steel Mill, this ratio decreases to 1.10, which corresponds to numerous literature data. The choice of isotope ratio is crucial for obtaining more detailed information about the nature and sources of technogenic lead contamination of soils. Thus, in soils with a low lead content, according to the values of the isotope ratio ²⁰⁸Pb/²⁰⁷Pb, lead is released associated with another source of pollution, presumably from a city thermal power plant operating on coal.

From 1978 to 2021, the migration parameters and dynamics of the distribution of ¹³⁷Cs in arable and virgin soils of the Tula region were studied. Identical patterns of distribution of ¹³⁷Cs from global and Chernobyl fallout in the soil profile of leached chernozems were revealed. On arable land, agrotechnical measures contribute to the uniform distribution of ¹³⁷Cs in the arable soil layer. In virgin soil horizons of chernozem soils of meadow phytocenoses, the processes of redistribution of radionuclides in the surface layers were most active in the first 10-year period after the fallout, which this contributed to the equalization of ¹³⁷Cs content in layers 0–2 and 2–5 cm and its increase in the 5–10 cm layer to more than 30% by the beginning of 2000. Nowadays, more than 75% of the ¹³⁷Cs content in virgin chernozem soils of the Tula region is concentrated in the upper 15 cm layer, and the penetration depth of radionuclides reaches 40–45 cm.

From 1978 to 2021, the migration parameters and dynamics of the distribution of ¹³⁷Cs in arable and virgin soils of the Tula region were studied. Identical patterns of distribution of ¹³⁷Cs from global and Chernobyl fallout in the soil profile of leached chernozems were revealed. On arable land, agrotechnical measures contribute to the uniform distribution of ¹³⁷Cs in the arable soil layer. In virgin soil horizons of chernozem soils of meadow phytocenoses, the processes of redistribution of radionuclides in the surface layers were most active in the first 10-year period after the fallout, which this contributed to the equalization of ¹³⁷Cs content in layers 0–2 and 2–5 cm and its increase in the 5–10 cm layer to more than 30% by the beginning of 2000. Nowadays, more than 75% of the ¹³⁷Cs content in virgin chernozem soils of the Tula region is concentrated in the upper 15 cm layer, and the penetration depth of radionuclides reaches 40–45 cm.

The study of ¹³⁷Cs and K behavior in «soil-plant» system of chernozem zone in remote period after Chernobyl accident was carried out. Experimental plots in agrosystems such as wheat, soybean, buckwheat, rapeseed, sunflower, grass mixture, and natural biosystem of a dry meadow were selected in the central part of Plavsk radioactive hotspot in Tula region. The level of ¹³⁷Cs soil contamination was 171 ± 26 kBq/m² (498 ± 100 Bq/kg). Average gross K content in soils was 2,0 ± 0,1%, including exchangeable K — 235 ± 54 mg/kg and non–exchangeable K — 816 ± 116 mg/kg. Vertical distribution of ¹³⁷Cs within contaminated 30-cm soil layer of agrosystems, as well as gross K, was uniformly accumulative, while K_ex and K_non-ex distribution was regressive and accumulative. At the same time, ¹³⁷Cs microdistribution in root zone was invariant, and gradient enrichment of soil near the root surface was shown for mobile forms of potassium. Intensity of ¹³⁷Cs transfer from soils to plants for all studied crops was 1–2 orders lower than intensity of K root uptake. Element distribution between plant organs differed. ¹³⁷Cs distribution was acropetal for Cereals and basipetal for crops from other families, and K was distributed basipetally in all tested plants.

The aim of the work is to summarize the data available in the scientific literature on the values of the ¹³⁷Cs/¹³³Cs isotope ratio in soils and vegetation cover of forest ecosystems in radioactively contaminated and background territories. The values of the specific activity of ¹³⁷Cs and the concentration of ¹³³Cs presented in radioecological studies are unified by calculating the molar ratio of these isotopes. Based on the generalized literature data, it is shown that the values of ¹³⁷Cs/¹³³Cs in soils, forest litter and vegetation increase in radioactively contaminated areas. In background regions exposed only to global radioactive fallout, the isotopic ratio of ¹³⁷Cs/¹³³Cs is about 0,1–1,0 (× 10^-8), whereas in the Chernobyl fallout zone it increases by 1000–100 000 times. The isotopic ratio of ¹³⁷Cs/¹³³Cs decreases down the soil profiles in various forest ecosystems. Spatial variation of the ¹³⁷Cs/¹³³Cs ratio in litter is associated with the diversity of ecotopes in forest biogeocenoses. The alignment of the values of the ¹³⁷Cs/¹³³Cs ratio in the vegetation cover and upper soil horizons indicates the achieved equilibrium of technogenic ¹³⁷Cs with natural stable ¹³³Cs in the biogeochemical cycle of this element. A comparative study revealed that the isotopic ratio of ¹³⁷Cs/¹³³Cs increases in the following range of plant cover representatives: Bryophyta < Sorbus aucuparia < Lichenes < Russula vesca < Frangula alnus < Polypodiophyta. For fungi, interspecific differences were noted in the following increasing series in the isotopic ratio ¹³⁷Cs/¹³³Cs: Lactarius deliciosus < Sarcodon scabrosus < Suillus bovinus < Tricholoma saponaceum < Lepista nuda < Russula delica < Macrolepiota excoriata. For the reference species of coniferous trees — Pinus sylvestris - the isotopic ratio of ¹³⁷Cs/¹³³Cs in the forest area of the Bryansk region polluted by Chernobyl fallout increases in the following number of components: roots < large branches < trunk wood < needles < small branches < cones.

The article provides an overview of the results of long-term studies of the migration of radionuclides in the composition of lysimetric waters. The features of lysimetric studies at various stages of radioecology development are considered. It is noted that the use of lysimeters for a long time was limited to low levels of radionuclides in soil solutions, and large-scale studies began after the Chernobyl fallout (1986). It is shown that the greatest output of radionuclides in lysimetric waters occurs in forest, especially coniferous phytocenoses, the least — in meadow and agrophytocenoses. In the long-term dynamics, the maximum intensity of radionuclide migration in the lysimetric waters is observed in the initial period after aerial precipitation, in the seasonal period — in the summer. A small amount of radionuclides migrates with downward water flow. Annual outflow with vertical subsurface runoff varies depending on soil-climatic conditions, the period after precipitation, the thickness and depth of the layer. Annual outflow from the forest litter layer varies from tenths to units of percentage, from the layer 0–20 cm — from hundredths to tenths of a percentage from the total radionuclide supply in these layers. The relative output of ⁹⁰Sr is much bigger than ¹³⁷Cs. In soil solution from 70% to 90% radionuclides [¹⁴⁴Ce, ²³⁹Pu ¹⁰⁶Ru ,¹³⁷Cs and ⁹⁰Sr] are in the form of radionuclide-organic compounds of various molecular weights. 

We studied the ecological state of the soils of the seven most visited recreational areas located throughout Moscow: Losinyi Ostrov, Park Pobedy, Ostankino, Sokolniki, Izmailovo, Kuzminki-Lublino, and Tsaritsyno. Soil samples were collected in summer of 2018 at three sites in each park. The concentrations of 38 chemical elements (Na, Si, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Br, Rb, Sr, Mo, Sb , Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Tm, Yb, Hf, W, Au, Th, U, Cd, Pb and Cu) in soil samples were determined using neutron activation analysis and atomic absorption  spectrometry. We made the sanitary-hygienic and ecological-geochemical assessment of soils samples and identified slight exceedances of approximate permissible concentration by elements belonging to the first hazard class (As, Cd, Zn). Also, we calculated the total pollution index. The moderately soil pollution by elements belonging first and third danger class was found in the territory of the following parks: Sokolniki, Izmailovo and Park Pobedy. The total pollution index calculated using all trace elements indicated that 50% of the sites belonged to the dangerous pollutionies. Sb, Th, Tb, Cs, and Hf significantly contributed to the total pollution. The highest pollution indices were found in soils samples collected on the territory of the Eastern administrative district in Sokolniki and Izmailovo parks.

In Russia, the lands with oil contaminated soils exceed tens of thousands hectares. However, to date, there were no unified approaches to the rationing of oil and petroleum hydrocarbons (PH) in soils, a guideline to choose optimal evaluation indicators. The response of plants in the pot experiment could provide significant results for assessing and rationing of PH content in soils and their use in agriculture after land remediation. In this work we assessed the response of higher plants as a marker of the direction and intensity of biological processes in soils in the pot experiment under oil contamination to justify the standards of permissible residual content of PH in soils of agricultural lands. The composition and properties of Luvic Chernozems, Calcic Chernozems, Voronic Chernozems (WRB, 2015) used in the pot experiment, which was carried out in a month after the soil contamination with crude sulfur-containing oil, were investigated. The effect of different oil doses on the bioproductivity of wheat and peas was evaluated. Wheat in terms of dry biomass showed higher sensitivity to PH, containing medium and heavy fractions, than peas. Rationing the PH content in chernozems, a nonlinear regression model described by a logistic curve was applied. The quality standard values found for wheat biomass was 0,9; 0,4; 1,0 g * kg^-1 for Luvic Сhernozems (humus content ~ 9,8%, sandyloam texture); Calcic Chernozems (humus content ~7,6%, clay loam texture), Voronic Chernozems (humus content ~12.8%, loam texture), respectively. The residual PH contents, found as 30% of soil functioning change, which corresponded to the risk level of soil degradation, estimated by the soil fertility parameter — dry wheat biomass were 1,2 g·kg^-1 for Voronic Chernozems; 0,5 g·kg^-1 — Calcic Chernozems; 1,1 g·kg^-1 in Luvic Chernozems.

New indicators of lanthanide affinity for carrier phases in the soil, based on the rationing of lanthanide concentrations by their soil clarks, are proposed. This made it possible to obtain an original indicator of the affinity of lanthanide A_LN to carrier phases in soils. The indicator of affinity of lanthanide A_LN showed its advantage over the accepted pC_Ln index in the analysis of Russian and Swedish soils.

Salt neoformations in sandy and silty loam soils of the Aral Sea dried bottom in the south-western part were studied by X-ray fluorescence, electron microscopic, sedimentation methods of analysis and laser diffractometry. The surface layers of soils are significantly saline and enriched with CaCO₃. The distribution of CaCO₃ over the area is quite uniform, which indicates relatively close conditions of its formation during desiccation. The salt content varies from 0.4 to 1.2% in sands and from 3.1 to 5.8% in silty loam. The latter are characterized by the highest salinity, when, in addition to gypsum and halite, readily soluble salts are formed: eugsterite (2Na₂SO₄^.CaSO₄.2H₂O), astrakhanite (Na₂SO₄^.MgSO₄^.4H₂O), and mirabilite (Na₂SO₄^.10H₂O). Precipitation of calcite upon drying leads to the formation of CaCO₃-ooids in sands and CaCO₃- microaggregates from clay and silty particle in silty loam. The reason for the increased activity of easily soluble salts in the processes of aeolian transport has been established. This transport and, correspondingly, the salinization of adjacent territories are facilitated by the blocking of adsorption centers in clays by calcite, which prevents the binding of easily soluble salts in clay-salt microaggregates.

We present a review of the literature data and the results of our own studies on the influence of soil invertebrates of the macrofauna size class on the processes of creating and maintaining the heterogeneity of soil properties in the temperate zone. Significant changes in physical, chemical and biological parameters of soils, compared with background indicators, were noted in excrement and associated soil aggregates, as well as substrates — products of vital activity of key groups of large invertebrates, such as earthworms, diplopod millipedes, diptera and coleoptera larvae, woodlice, and ants. Most of the research is related to the impact of earthworms and ants on soils, whereas for other groups few reports exist. The results of the research will be useful for practical purposes, in particular for the development of sustainable anthropogenic ecosystems.

Methodological aspects of identification, accounting, analysis of development and interaction of soil heterogeneities of various genesis are considered. The modern views on their origin are summarized, methodigical approaches and features of the study are shown. Conceptual views in the field of soil science are presented, which allow a deeper and more comprehensive approach to the assessment of such a phenomenon as soil heterogeneity: the hierarchical orga- nization of soil space, historical and modern («soil-memory» and «soil-moment») components of soil heterogeneity, soil succession and their role in understanding the essence of the phenomenon under consideration. The concept of primary and secondary heterogeneities is formulated, which are defined as a universal feature that manifests itself at all levels of the organization of the soil space and is formed, respectively, by paleo- and cenotic mechanisms. It is shown that the primary heterogeneity is the result of the action of pedogenesis factors, which reflects the desire of the soil to find an equilibrium state with the environment. Secondary heterogeneity is a consequence of the action of various natural and anthropogenic factors that bring the soil system out of equilibrium. A scheme of factors and causes of primary and secondary heterogeneities is proposed and formalized, as well as a scheme of modern factors and causes leading to the emergence of secondary heterogeneity of various origins. The priority role of the works of E.A. Dmitriev and his school in the formation of modern views on the heterogeneity of soils, in the development of field and statistical methods for analyzing the assessment of this natural phenomenon, which he put in a number of direct objects of research, is emphasized.

Th e article discusses the current approaches to the assessment of the heterogeneity of soil properties. On the example of the experimental plot (106 ha) of the RUNE “Grodno Zonal Institute of Plant Industry of the National Academy of Sciences of Belarus” it is shown that ignoring the intra-fi eld heterogeneity leads to even more signifi cant diff erences. On the experimental fi eld, using satellite images and multi-temporal indices EVI, microplots with an area of 50 to 200 m2 with а signifi cantly reduced level of eff ective fertility, up to the death of plants, were identifi ed, on the basis of which а sampling grid was developed. During the fi eld work, 214 pHKCl samples were taken with а sampling step of 70 m and 53 additional samples in the “problem areas”. Using geostatistical methods, data on the spatial heterogeneity of pHKCl were obtained, the degree of spatial dependence and the accuracy of the results obtained were estimated for various numbers of samples (107, 216, and 268 points). Further use of stochastic modeling made it possible to construct high-precision cartograms of acidity with а pixel resolution of 4 m and 12 m. We also showed that the use of cell sizes less than the processing device is not useful for solving applied issues of precision farming. Probabilistic-statistical models were obtained, represented by cartograms of mean square errors and the probability of the phenomenon. Th e resulting cartograms showed the presence of ultra-acidic soils in the “problem zones”; such а reaction also determines the presence of toxic aluminum compounds and extremely low calcium and magnesium contents, which jointly lead to the absence of seedlings of cultivated vegetation. А detailed accounting of soil acidity in comparison with а classical agrochemical survey provided savings of $ 2807 by the application of СаС03, which made it possible to fully compensate for the additional costs of taking and analyzing а larger number of samples.

The regularities of the spatial distribution of ¹³⁷Cs in forest soil at the microlandscape level in semiromophic and hydromorphic conditions in the Bryansk region at different measurement steps with the KORAD radiometer (10, 2 and 0,5 m) are investigated. The variability of the ¹³⁷Cs stock obtained by two devices differing in the size of the sampling area (RPO) is compared: 1) CORAD radiometer 2) sampler D=14 cm. The ratio of the variability of the ¹³⁷Cs distribution obtained by field radiometry to the sampling data (CVcorad/CV sample) for the entire site is 0,63; for the hydromorphic part, B1-1 is 0,87. For the entire site (size 50x80 m), a weak spatial correlation was revealed (the effect of a "chessboard"), for a local hydromorphic site, a strong correlation with a rank of 1,4 m.

The aim is to present statistical portrait of soil cover pattern for farm as series of cumulative statistical distributions of soil horizon’s depth and thickness. The object is soil combinations of Haplic or Luvic Protosodic Kastanozems and Solonetzs at the experimental station “Irrigated” localized in southern-western end of the Volga Upland near the Volga-Don Channel. Majority of empirical statistical distributions of soil horizon’s depth for general data fetch (182 profiles) cannot be approximated by normal one. Nonparametric indices are used. Separation of soil groups using substantial properties does not guarantee data fetches with normal distribution for all morphometric properties. Soil types and subtypes according to Russian soil classification system have different complex of statistical distributions of soil horizon’s depth. Many differences are related to changes of carbonate profile, development of secondary solonetzicity, crust formation, local surface washout and accumulation of upper part of arable horizon.

Soil respiration, which is one of the main fluxes in the global carbon cycle, is characterized by high temporal and spatial variability. Based on the year-round continuous 21-year monitoring of the respiration of soddy weakly-podzolic soil in the forest and meadow coenoses of the southern taiga zone, an assessment of the temporal variability of CO₂ fluxes from soils was made at different time levels: monthly, seasonal, and annual. The values of total respiration of soddy weakly-podzolic soil varied most significantly at the monthly averaging level (coefficient of variation, CV=25–56%), while the variability of the annual respiration of soils was 20–22%. At the seasonal averaging level, the highest variability (CV=39–44%) was noted for winter CO₂ fluxes from soils, whereas the variability of total soil respiration in the other calendar seasons was close and amounted to 26–29%. The effect of the type of cenosis on the total CO₂ fluxes from the soddy weakly-podzolic soil was statistically significant both at the annual averaging level and in all calendar seasons of the year, except for winter. The most stable indicator characterizing the seasonal distribution of CO₂ fluxes within a year is the contribution of the warm period (May–October) to the total annual CO₂ flux from soils, which averages 73–77%. Its variability over 21 years of observation in both coenoses was 8%. It can be recommended to use this indicator to obtain estimates of annual CO₂ fluxes from soils based on field measurements carried out only within the growing season. The numerical experiments performed have shown that continuous measurements of CO₂ emission from soils for five consecutive years reduces the variability of annual and seasonal CO₂ fluxes from soils by more than 2 times compared to a one- or two-year measurement period. This makes it possible to recommend a five-year observation period as the optimal required for obtaining adequate values of annual and seasonal CO₂ fluxes from the soils of the southern taiga zone. 

The current state of the problem of soil mapping is considered. It is shown that there has been a replacement of traditional soil mapping methods by methods based on geoinformation digital and remote sensing technologies. The main advantages and disadvantages of the currently used soil mapping methods are outlined, and the necessity of taking into account the level of generalization of the information used in the process of soil mapping is demonstrated. We demonstrated the errors arising in soil maps when digital spatial data with different levels of information generalization is used. The most promising directions in the development of soil mapping methods are identified. It is shown that the primary attention should be paid to the development of digital soil mapping methods based on remote sensing data, which contain the most accurate information on the spatial variation of the surface soil horizon properties. The use of methods of spatial interpolation of point data is less accurate than the use of remotely sensed data. But the latter allows us to confidently detect only certain soil properties and not all of those necessary to create soil maps in the traditional form. Mapping individual soil properties is a more promising approach. Maps of individual soil properties are more convenient and accurate for evaluating soil and land resources. In the future, they can be used as a basis both for the re-creation of soil units in terms of accepted soil classification and for the creation of soil maps in traditional form (with the reflection of classification units of soils on them). But for a complete transition to the mapping of soil properties, it is necessary to deepen research in studying the spectral reflectance of the soil surface and its relationship with the properties of the underlying soil horizons.

The article is a review of the scientific problems that the Honored Professor of the Lomonosov Moscow state university Evgeny Anatolyevich Dmitriev. The main area of his scientific interests is the genesis of soil and land cover data. Numerous works carried out under his supervision convincingly demonstrate the influence of sampling methods on the results of determining certain soil properties. As a consequence, this influence also extends to the final conclusions, which can be highly distorted if the method of obtaining them is not taken into account. In an attempt to solve the question “What classifies soil classification?”, he develops the concept of “single soil”, which can be the object of soil classifications, not being directly a soil body, but acting as a kind of standard element of sampling. Theoretical understanding of the influence of heterogeneity of soils and soil cover at all hierarchical levels on the features of its “life” is the subject of the second part of the scientific legacy of E.A. Dmitriev. He puts forward the concept of soil bodies of different dimensions, shows the influence of the dimensional characteristics of these bodies on soil regimes and, in particular, on the water regime, and discusses the need to study soil regimes at different hierarchical levels. To fix the heterogeneity of the soil and soil cover, he developed special devices, with the help of which studies were carried out on soddy-podzolic, gray forest, chestnut, and other soils.

The features of anthropogenic transformation of natural chestnut soils and genesis of urban soils and conditions of the dry-steppe natural zone on the territory of Volgograd were studied in detail. The study was carried out by comparing the morphological characteristics of natural soils and their anthropogenic-modified counterparts. A morphological description was carried out for each of the 16 transects. The morphological characteristics of urban soils and chestnut soils of the city outskirts were compared. Under the influence of urban pedogenesis, natural light humus horizons AJ disappear, and the average thickness of diagnostic xerometamorphic horizons BMK decreases. The upper boundary of accumulative-carbonate horizon BCA lowered relative to the surface by an average of 32 cm compared to natural chestnut soils. Under the influence of urban-techno-pedogenesis there appeared inclusions represented by debris of building materials and garbage, accumulated in the process of human settlements functioning, the structure, density, nature of boiling from HCl 10% have changed. Modern surface horizons often boil off HCl 10%. In the landscaped recreational areas of the city, carbonate leaching has occurred due to irrigation of the area. The variants of morphological transformation of chestnut soils formed on the territory of Volgograd as a result of urban pedogenesis have been revealed. The first variant - soils of initial stages of technotransformation, with changes at the level of the upper horizons. The second option — soils with thick urban horizons, overlapping the preserved diagnostic horizons. The third option — burial of natural rocks by man-made soils of varying thickness with almost complete destruction (removal) of natural soil horizons. The fourth option — soils with thick humus horizons formed at the expense of intensive infusion of organic matter in underpourings of compost. It is noted that most of the soils of the city have profiles, completely formed on man-made sediments, and do not contain natural soil horizons in the upper 1,5 m thickness. According to the Field Identification of Soils of Russia, the studied soils of the first variant of transformation are defined as urban-stratified. The soils of the other options of transformation can be attributed to man-made surface formations. The content of organic carbon in the urban, technogenic, and replanted horizons averages 1,1, 0,25, and 1,6%, respectively. Chemical analysis of urbic, reclamation, and technogenic horizons revealed a low content of readily soluble salts — 0,14% and carbonates — 0,9%. Density in UR and RAT horizons is on average 1,4─1,43 g/cm³, in TCH horizons — 1,55 g/cm³. Buried horizons average density is 1,43 g/cm³ in AJ, 1,49 g/cm³ in BMK, 1,62 g/cm³ in B, and 1,54 g/cm³ in BCA, which is higher than average density for native chestnut soils. Also for the buried horizons is characterized by leaching from salts (mid. 0,2%) lower values of calcium carbonate content than in the background, alkalinization of the environment, as well as a decrease in organic carbon by an average of 0,35% in the AJ, BMK, and B horizons, and by 0,28% in BCA. The average CaCO3 content in the upper humus and median horizons is 1,4% and in the carbonate horizon 4,3%. The obtained results allow us to study in more detail the peculiarities of the genesis of urban soils and the anthropogenic transformation of natural chestnut soils in urban conditions of the dry-steppe natural zone.

Water-soluble organic substances (WSOM) of sod and humus horizons of Mollic Gleysol artificially saturated to full moisture capacity were isolated by sequential centrifugation from pores with a diameter of more than and less than 30 microns. The total concentration of carbon and phenolic compounds, the absorption and fluorescence spectra of the solutions do not differ significantly, but a strong variation in the parameters (the ratio of maximum and minimum values is 415 times) indicates the heterogeneity of the composition of the extracted substances. The concentration of simple phenolic acids in solutions of large pores of the humus horizon is 48 times higher than in smaller ones, salicylic, benzoic and cinnamic acids predominate (75% of the total amount). In small pores, p-hydroxybenzoic and benzoic acids predominate (67% of the total amount). Dissolved organic matter (DOM) of soil solution of the Podzolic soil (ELBTg horizon, moisture 22%), were obtained by tension lysimeters from pores with a diameter of more and less than 14.7 microns. DOM in solutions from large pores contain more C, N, phenolic compounds and, according to the absorption spectra, have a large molecular weight and a degree of aromaticity. Organic substances from small pores are more hydrophobic and are characterized by a greater C:N ratio; these features potentially promote DOM resistance to decomposition. Predominant localization of phenolic substances in large pores is favourable for the conservation in soil since transport with water flows assist their chemical stabilization in the lower horizons as organo-mineral compounds. 

Under the conditions of a laboratory incubation experiment, the effect of the introduction of crop residues (rye straw) and mineral nitrogen fertilizer on the formation of nitrous oxide by Albic Retisols was studied. It was found that the increase in the carbon content of microbial biomass is linearly related to the mass of introduced plant residues. An important indicator characterizing the system under study is the C:N ratio of microbial biomass and its dynamics both with changes in the amount of crop residues introduced and over time. At the ratio C:N = 40 in plant residues at the early stages of their decomposition in the soil, the predominant process of microbial nitrogen immobilization is replaced by the predominance of the process of mineralization of organic nitrogen compounds. It is shown that the maximum immobilization "capacity" of microbial biomass in relation to nitrogen is achieved at a ratio of C:N in the substrate equal to 20-40. The dependence of the intensity of nitrous oxide emission by soils on the amount of crop residues introduced has been established. It is shown that the maximum values of the emission factor are characteristic of the experimental variants with the introduction of a substrate enriched with nitrogen (C:N = 7,5-10), which may be associated with better decomposition of plant residues under conditions of better nitrogen supply.

The features of the ground cover in connection with the use of care in typical urban plantings in Moscow are determined. The character of plantings care determines the main features of ground cover more than the type of tree species. As a result of planting care, nemoral shade-tolerant species in the grass layer are actively replaced by meadow nitrophilic and ruderal species belonging to annuals and turf grasses, which contributes to an increase the biological cycle intensity.  In urban ecosystems, the indicative role of plants in relation to soil properties is reduced due to the lack of direct long-term relationships between these components.

Within the landscapes of the upper reaches of the Klyazma River, the long-term component composition of natural waters in the system has been studied: snow waters — soil solutions — soil-ground waters — surface waters. It has been determined that the regular excess of the content of the main macro- and microelements in soil solutions in comparison with snow waters at subsequent stages is first replaced by an increase in the concentration of components in soil-ground water, followed by a decrease in the content in surface waters — streams and river waters. It is shown that the relatively high mobility of sodium, magnesium, potassium and calcium, and of the anions chloride and nitrate ions, is accompanied by a significant decrease in the mobility of elements of the family of iron, copper and zinc at the transition from groundwater to surface water. This explains the wide distribution of segregated forms, presented in the form of nodules in soils of semi-hydromorphic landscapes, up to ortsands, and in the boggy conditions of near-terrace depressions on the border with the super-aquatic landscape, the formation of typical bog ores. Thus, the composition of natural waters and its change serves not only as a good, but also a necessary tool for explaining the features of migration of elements in the soil — natural water system.

Methodological problems of the quantitative assessment of pollution of urban soils by benzo(a)pyrene and their bioremediation are considered by the example of the Moscow metropolis. Available materials of scientific publications and official reports of the «Mosecomonitoring» municipal system about pollution of urban soils by benzo(a)pyrene and the patterns of its dynamics were used. The methodological basis of the study was mathematical modeling, including both non-linear regression analysis in the S-Plot-11 program and numerical computer simulation in the Matlab-7 software. Analysis of published materials reveals at least a double excess of the maximum permissible level of pollution of urban soils by benzo(a)pyrene at 70% of the territory of the Moscow metropolis, with a high probability of an extremely high degree of pollution in several dozen MPCs at 10% of the city's area. Unlike known works in this field, the study links such a negative situation not with the resistance of benzo(a)pyrene in soils, but with its high technogenic load. A simple kinetic model, verified for experimental information on biodegradation of benzo(a)pyrene in soils, makes it possible to assess the permissible limits of technogenic load, guaranteeing the self-cleaning of urban soils from this dangerous pollutant in the conditions of Moscow.

It is shown that the cultural layers of urban ecosystems are distinguished by the accumulation of all groups (general, mineral, organic) phosphorus compounds. At the same time, the humus of the horizons of anthropogenic origin is enriched in organic phosphorus in comparison with natural analogues by 3-10 times. Due to the neutral and close to neutral character of soil acidity, the mobility of all groups of phosphorus compounds is reduced, which is the main reason for their fixation in the profile of stratozems. It was found that the group composition of phosphorus in the soils of settlements and settlements does not reflect the zonal patterns of accumulation and profile distribution of phosphorus, but it can serve as a reliable indicator of the presence of anthropogenic activity in the past.

Urban soils contain a substantial pool of organic matter (OM), the decomposition of which leads to intensive CO₂ emission that important in terms of global climate change. The OM decomposition increases in line soil temperature, the magnitude of such effect largely depends on the soil physicochemical properties. At the same time, the contribution of the functional microbial diversity on the temperature sensitivity of OM decomposition (Q₁₀) is still poorly understood, and especially for urban ecosystems. Consequently, our study aimed to assess the effect of the microbial functional diversity on the Q₁₀ value for urban soils considering its physicochemical properties. In the St. Petersburg, Moscow, Voronezh and Krasnodar, located in different bioclimatic zones (southern taiga, mixed forests, forest-steppe and steppe, respectively), four parks were selected. In each park the samples were taken from the topsoil (0-10 cm layer). In soil samples, decomposition of OM was determined at the temperature 10, 20, 30, and 40°C for the subsequent calculation of Q₁₀ value. The soil physicochemical (moisture, texture, pH, content of C, N, P₂O₅, K₂O) and microbial (functional diversity, biomass) properties were determined as possible Q₁₀ index drivers. The Q₁₀ value in humus horizons of urban soils was mainly correlated with its texture, moisture C and N contents, while the microbial functional diversity was correlated with P₂O₅. The regular distribution pattern of Q₁₀ and the studied soil properties of urban parks along the latitudinal gradient has not been found, however a negative relationship between Q₁₀ and the microbial functional diversity has been revealed (R² = 0.50). Apparently, the high microbial functional diversity contributes to a decrease of the temperature sensitivity of OM decomposition.

Complexes of cultured saprotrophic bacteria and yeasts from different components of soil constructions (humus soil horizon and peat) were studied simultaneously with the assessment of auxin-producing activity (synthesis of 3-indolylacetic acid, IAA), of some bacteria and yeast strains isolated. The study was conducted at the stage of laying two variants of constructions in Syktyvkar, formed from components of local origin (variant 1) and imported (humus soil horizon, Moscow, peat "Seliger-agro", Tver region) (variant 2).

The taxonomic structure of microbial complexes isolated from the studied substrates had significant features of similarity. At the same time, components of variant 1 revealed a greater diversity of cultivated saprotrophic bacteria (Bacillus species) species resistant to adverse environmental conditions as well as the presence of psychrophilic basidiomycete yeast Leucosporidium scottii, which was not found in the components of variant 2.

The average IAA production by the yeast strains studied was 647.6 µg/L and by saprotrophic bacteria - 741.3 µg/L. The highest values of IAA concentration were found in the culture liquid of the yeast Tausonia pullulans (strain Y-6) - 3362.6 µg/l, isolated from the humus soil layer of variant 1, and of the two saprotrophic bacteria Flavobacterium рsychrophilum (strain B-7 - 2616.8 µg/L and B-5 - 1056.3 µg/L), isolated from the humus soil horizon in variant 1 and from peat of variant 2. For strains of the yeast Leucosporidium scottii and the cultured saprotrophic bacteria Flavobacterium psychrophilum the ability to synthesize IAA was found for the first time. 

We used sequential static chemical extraction methods for studying soil pollution with heavy metals. This allowed determining the amount of metals extracted with this reagent. The new equipment for dynamic extraction of HM and obtaining extractograms, opens up additional possibilities: to determine the number of particles’ groups that differ in resistance to this reagent and to determine the statistical indicators of each group of particles. The technique for decrypting extractograms is based on their deconvolution into a series of asymmetric Gaussians corresponding to a separate group of particles – carriers of HM. The statistical indicators of Gaussians include the relative stability of each group of particles to this reagent, their dispersion D, asymmetry As, and excess Ex. Statistical indicators of Ca-Mg particles of HM carriers in urban soils show a high heterogeneity in the resistance of particles to acetic acid compared to particles in non-urban soils. The probable reason for the difference between urban and non-urban soils is a different composition of Ca-Mg minerals: , most Ca-Mg minerals in non-urban soils are carbonates. Urban, initially carbon-free soils are contaminated with Ca-Mg-containing construction waste: cement, lime and asbestos, and also contain secondary carbonates formed from Ca-Mg-waste. Urban acetic soluble pollutants belong to the following groups of minerals: technogenic hydroxides, silicates and aluminates of calcium and magnesium, which greatly distinguishes their chemical properties from the properties of carbonates. The abundance of pollutant forms as carriers of HM determines the diversity and heterogeneity of groups of particles soluble by acetic acid in urban soils.

The article discusses the existing methodological approaches used in Russian and foreign studies of urban soils. The analysis of methods for studying the soil cover as an object of landscape design, considering its formation and functioning on the example of the Moscow city. Information is provided on the territorial and functional organization of urban space. From the point of view of methodological approaches for the study of urban soils, it is proposed to divide them into two groups: uneven-aged soils with bulk surface horizons from various recultivants, formed according to design documents, and natural and surface-transformed soils without filling layer. The features of methodological approaches for studying each soil group are considered. It is noted that the material composition of the ground materials from which urban soils are formed has a significant impact on their structure, properties and functioning. The use of ground materials of different composition and properties for the formation of the upper part of urban soils, sometimes an unknown history of their functioning and land use, and possible numerous violations cause extremely high and most often unsystematic spatial and temporal variability of urban soils. With the increasing interest of the scientific community in the qualitative assessment of the urban environment, the most promising is the development of methods for studying the resulting ecological functions of urban soils using integral indicators, as well as the development of approaches, methods and technologies for creating urban soils that meet the criteria of green environmental management.

Key words: soils of Moscow city, zoning of urban areas, soil science methods, urban ecology, ecological functions of soils, ground materials.

The estimation of the radial migration of petroleum hydrocarbons (TPH) in soil profile and their inflow into lysimetric leachates was done to establish acceptable TPH limits in main soil types of Sakhalin Island. The maximum concentrations of TPH, especially medium and high-boiling fractions of TPH, were accumulated in peat and humus horizons, as well as in soil horizons, characterized by heavy loam or clay granulometric composition, which could be considered as radial geochemical barriers to the migration of pollutants. Benzene and its homologues were detected in filtrates from soil monoliths, after passing a water volume corresponding to three-quarters of the annual precipitation, yet these compounds were not revealed after passing the annual precipitation rate through the soil. The toxicity of the leachates was assessed in bioassay with ceriodaphnia and ciliates. The criteria for establishing the acceptable TPH norms in soils according water migration index can be: concentration of TPH, the content of monoaromatic compounds in leachates and their toxicity for hydrobionts in lysimetric experiments.

The migration of the water-soluble fraction of petroleum hydrocarbons in typical soils of Bashkortostan is studied. In a lysimetric model experiment, the possibility of water migration of petroleum hydrocarbons in Fluvic Phaeozems, Haplic Phaeozems and Amphiskeletic Pantocalcic Chernozems was revealed. Among the dissolved organic substances that pass into lysimetric waters from oil-contaminated soils, the components that are not extracted by hexane, but have fluorescence in water at the wavelengths typical for petroleum products are revealed. These substances differ from soluble organic matter of background soils by higher HIX humification indices and presumably represent oxidized products of transformation of petroleum hydrocarbons. Lysimetric waters from all oil-contaminated soils are characterized by biotoxicity, regardless of the presence of non-polar petroleum hydrocarbons. The toxicity T-index positively correlates with the content of dissolved organic carbon and chloride ions that accompany soils oil pollution.

Surface waterlogged soils, drained by ceramic and plastic drainage, are an analogue of large-area lysimetric installations, the drainage runoff in which is represented by gravitational waters like lysimetric waters. The drainage runoff module in the spring and autumn periods at landfills drained with plastic and ceramic drainage, and its dependence on the humidity of the year have been established. It is shown that drainage transforms the type of water regime from stagnant-washing to washing. The long-term and spatial dynamics of the removal of the silty fraction of soils and iron compounds has been studied. The removal of chemical elements with drainage runoff and its influence on the intensity of the loessivage process in agro-gray drained soils have been established.

The main components of the CO2 balance - emission from the surface, removal with lysimetric runoff, and dynamics of reserves in a 1.5 m soil layer, taking into account interphase equilibria, were quantitatively assessed in a 2-year soil-lysimetric experiment. A significant (up to 20-90%) contribution of lysimetric runoff to the total gas exchange in cold weather (autumn-winter) against the background of a small (0.3-3.7%) share during the growing season (spring-summer) is shown. Due to the unsteadiness and inertia of gas accumulation / unloading processes inside the soil, emission from the surface does not adequately reflect the gross CO2 production by the soil volume, underestimating in the spring-summer period and overestimating in autumn. The obtained 2-year correlation between emission and gross-production indicates the possibility of a 1.3-1.4-fold underestimation of the dissimilation component of the carbon cycle in the traditional emission assessment of soil respiration.

The theoretical equation of the concentration of trace element compounds entering the soil with atmospheric precipitation as a function of depth and time is tested on the example of data on the long-term dynamics (1965, 1995, 2006, and 2013) of Cu, Ni and Mn compounds in the soil profile under artificial phytocenoses of the MSU soil lysimeters. The obtained results indicate the possibility of using an analytical model for predicting the content of heavy metals in the soil profile.

Mineralization rates of soil organic matter (SOM) decomposition of non-remediated and remediated oil)polluted, as well as background soils from the main types of West Siberian middle taiga’s ecosystems were measured in laboratory experiments. Rates of SOM mineralization were measured by alkali absorption of CO₂ released from wet soil samples at 20°C (basal respiration). Because of linear character of cumulative curves of CO₂ release SOM mi neralization rates were expressed by mineralization index K1 equal to the annual amount of CO₂ released per 1 gramm of soil. K1 values varied in a range 0,123—1,578 mg СО₂/g/day. Highest value was found in background forest soil, lowest — in oil-polluted peat soil with extremely high oil content (544 g/kg). K1 values negatively correlated (K = –0,57) with oil content. SOM mineralization rates in remediated oil)polluted peat soils varied in a range — 0,31—0,85 mg СО₂/g/day

Abundance and diversity of soil saprotrophic bacteria complexes were monitored for two years on the territory of one of the large industrial cities of the European North of Russia, Syktyvkar. The work was carried out before and after quarantine in connection with the COVID-19 pandemic. The capital of Komi is characterized by a high population, and by tense environmental conditions according to the ecological standard. Studies were conducted in 2019—2020. Topsoils (0—10 cm) of urbanozems, horizon A in the park area in the urban space, as well as zonal undisturbed podzolic soil were analyzed. Comparison of the two)year monitoring results demonstrated a marked increase in the number and diversity of saprotro) phic bacteria complexes in 2020 both in urban and control soils (topsoil, 0—10 cm).

Detailed studies of Enterobacteriaceae demonstrated a decrease in the share of opportunistic (Enterobacter agglomerans, Citrobacter europaeus, Klebsiella oxytoca, Serratia marcescens, etc.) as well as fecal coliforms (Escherichia coli, Enterococcus faecalis) in urbanozems in 2020 — a consequence of a sharp and prolonged decrease in the anthropogenic impact on the environment. It can be viewed as a manifestation of the soil ability to “self-purification” when anthropogenic impact on the environment reduces.

The creation possibility of highly effective universal stimulating preparation for presowing seed treatment of various grain crops on the base of sorption)stimulating preparation (SSP), consisting of calcium bentonite (CB), humate (H), brewer’s yeast autolysate (BYA), and gibberellin (Gibb) is studied. The introduction of some non)ionic surfactants into the preparation composition results in the disintegration of bentonite aggregates into individual montmorillonite particles and an increase in the active surface of the sorption complex. It gives an opportunity by increasing the gibberellin concentration to improve the SSP efficiency in 1,5 times. As a result, 5)component composition (SSP-5), including CB, H, BYA, Gibb, PEG, is developed, and its efficiency on spring wheat of Lisa cultivar on sod)podzolic soil is 56%.

The introduction of other BAS into the preparation to make up a possible lack of these compounds in seeds showed that with an increase in the stimulation of some seeds for other ones, the supplementary adding of phytohormones reduces the overall effect. These data allow suggesting that it is not possible to create universal preparation highly effective for all seed.

Since gibberellin stimulates seeds development much more often than other phytohormones, we tested the SSP-5 action on seeds of different cultures and cultivars. It is established that, in most cases, this preparation effective for seed stimulation, but the efficiency values from its application vary markedly.

The simulation model of seasonal dynamics of ¹³⁷Cs in the components of the snytevoy oak forest ecosystem EcoradOak_CS_FW was further developed, which now includes first- and second-order consumers. The radiocesium redistribution in a full-scale food web of   a forest ecosystem of the type “soil—vegetation cover—herbivores—predators” is modeled. The algorithm used in the model allows us to take into account the influence of soil, meteorological, phenological and physiological factors on the behavior of radionuclide in the food web and predict radiological situations under various conditions of radioactive fallout. Data   on the contamination of animals with radiocesium obtained using the model are used to calculate the dynamics of the internal dose. The results of modeling can be used in the rationing of forest products of deciduous forests. The model is also applicable to the study of potassium redistribution in the trophic chain of a deciduous forest ecosystem.

In south taiga, as the former hayfields overgrow, the biomass of herbaceous layer decreases even before the formation of a closed tree stand. In the topsoil, increase of actual acidity   was observed, which was adequately reflected by the species of living ground cover;   a more distinct trend was revealed for light soils. The content and reserves of organic carbon in the soil of the hay meadow, where the mowing was preceded by perennial grazing, is rather high in comparison with the soils of hayfields without prior grazing. In general, after grass mowing stop, the content and reserves of organic carbon in topsoil decrease. Long)term cattle grazing slows down the postagrogenic dynamics of organic matter in meadow soils.

The litter properties of Moscow State University urban stands with a different type of  care, from lack of care to regular care, were studied using birch stands, lime stands and maple stands as examples. Simplification of the vertical structure as a result of care increases the open space inside the stands, changing the degree of shading and wind regime. For park stands, the special role in litter formation belongs to lateral wind transfer and care regularity, these factors influencing on litters pool and fraction composition. The use of stand care is accompanied by the withdrawal of from 50 to 90% of the stocks of litter, which leads to decreasing recirculation of organic matter and ash elements in urban ecosystems.

The characteristic of symbiotic relationships is presented on the example of vesicular-arbuscular mycorrhiza in the case of Trifolium pratenseL. at different succession stages of meadow phytocenoses. It is shown that the functional potential of symbiosis changes in the course of succession and is fully revealed under conditions of an undisturbed climax community. The fundamental possibility of biological diagnostics of the state of phytocenosis using discriminant analysis according to the indices of an individual legume plant, taking into account the symbiotic potential, has been demonstrated.

Under the conditions of a model vegetation experiment (30 days), the responses of microbial communities of agro-soddy-podzolic soil of two sites (Chashnikovo, Moscow region) with different organic carbon content (Corg 3,86 and 1,30%) to polymetallic pollution with heavy metals (HM: Cu 660, Zn 1100, Pb 650 mg/kg) and treatment with biochar (5%) and lignohumate (0,25%) Methods of classical inoculation on Czapek agar and analysis of soil lipid profiles by gas chromatography—mass spectrometry, an assessment of the differences in abundance colony forming units (CFU), the biomass of fungi and bacteria, the diversity of cultivated fungi in humus-rich and humus-poor soil. HMs did not have a significant effect on the number of CFU and the number of cultural-morphological types of colonies, but they reduced the biomass of fungi and bacteria in both soils, while this decrease was much more pronounced in a weakly humus soil. In addition, the differences between the soils manifested themselves in a different increase in the proportion of resistant melanized forms of fungi under the influence of HM in a highly humified soil — by 25,9%, and in a weakly humified soil — by 45,7%. The sensitivity and universal significance of structural indicators as indicators of the stability of microbial complexes under chemical contamination of soils of different humus content are discussed; among the studied, the most sensitive and reliable indicators include the assessment of the proportion of melanized fungi.

The characteristic of typical and humus petrozems of the most high-altitude belt zone of the Khibiny, formed under three predominant types of plant groups corresponding to different stages of primary succession, is presented. For these soils, there is no differentiation of the profile by the content of most elements, with the exception of phosphorus, which is concentrated in the surface organogenic horizons. According to many chemical and phy sicalchemical properties, the soils of the char belt are close to Entic Folic Podzols formed in the underlying mountain-tundra belt under shrubby vegetation. The biological activity of petrozems below or is comparable with this parameter in the soil of shrub tundra. It was found that as the structure of vegetation becomes more complex, the activity of microorganisms increases and the organic matter of the soil stabilizes. Overall, the microbial community of petrozems well adapted to extreme conditions.

Indicators of cadastral value of soils in agroclimatic subzones of agrolandscapes of the Irkutsk region are determined. The sensitivity of cadastral value calculation approaches to various soil and geographical conditions is shown. Low values of the cadastral value of agricultural land are due to low values of agroclimatic potential.

The article is devoted to the assessment of the influence of biotic, abiotic and anthropogenic factors on the dynamics of production processes of various ecosystems located in one natural and climatic subzone — the southern taiga of the Eastern European Plain.

The study was carried out on the example of four key sites in the Vladimir region, located in different landscape provinces in similar climatic conditions, but with certain differences associated with the characteristics of the soil and vegetation cover, anthropogenic load, and land use structure. Calculation of productivity indicators in carbon units is based on MODIS GPP/NPP data. The amount of organic carbon in the soil is determined according to the UN Food Organization (FAO) based on the Trends.Earth module of the GIS QGIS package.

Common to the four ecosystems is the course of changes in the indicators of vegetation productivity over the years against the background of its different absolute values. Favorable conditions for the accumulation of carbon in the soil are formed in areas with high productivity and a large number of overgrown lands. The results of analysis of variance ANOVA demonstrate that the factors of time and spatial position of key sites do not affect the content of soil organic carbon and gross biological productivity. Land use structure is a significant factor. It is shown that the insufficient productivity of some ecosystems is compensated by an increase in the productivity of neighboring ones, therefore, the preservation of intra-landscape diversity is a necessary condition for maintaining the stability of their functioning.

The composition of water extracts of soils developing within the het erolithic geochemical landscape of the Klyazma river basin in its upper reaches has been studied. The main factor that determines the content of water-soluble components is the genesis of soils and the position of the soil in a series of elementary landscapes. The specifics of the content of water soluble macro- and microelements in the soil profile outside the zone of anthropogenic influence and developing according to the eluvial- illuvial type is due to their natural organization, with the combination of podzolization in combination with texture organization. Under the con ditions of a supersquale landscape that has emerged from the flood regime, characterized by the complexity of the soil cover, the distribution of water soluble components in the soil profile is determined by the carbonate content and proximity to the surface of soil ground water. An additional factor determining the composition of soil water on the lowered elements of the relief is the underlying soil with peat bogs. It is shown that calcium is among the most important elements that determine the specificity of the studied heterolithic landscape. The composition of water-soluble components for each of the soils is specific, which is confirmed on the basis of the results of cluster analysis.

This article provides an analysis of structural and functional indicators of bacterial complexes taken for examination from the complete profile of the fens that form part of “Klukvennoye” and “Karbyshevskoye” wetland systems in the Tomsk Region. In the fens bacteria was found throughout all the profile. The number of bacteria was high and varied from 27 to 78 ´ 10⁹ cells/g of dry peat. This data was obtained by direct method using fluorescence microscopy. The high count of the saprotrophic bacteria (reaching up to 10⁸-10⁹ CFU/g of dry peat) was found by the plate method. Those results allowed to identify a trend, showing that the number of saprotrophic bacteria increased down the fen profile.  The results of this study give an opportunity to state for the first time that the index k ( k is a dimensionless universal characteristic of natural prokaryotic communities, k stands for microscopy/plate) in fen profiles does not increase, but decreases with depth. The following bacterial cultures were identified and isolated from the fens studied (those cultures were attributed to 10 taxa): Bacillus, Streptomyces, Arthrobacter, Microbacterium, Pseudomonas, Pedobacter, Flavobacterium, Dyadobacter, Janthinobacterium, Myxobacteriales. Bacterial cultures, representing Bacillus and Streptomyces genera, were dominant in the acrotelm. At the same time Pseudo-monas, Dyadobacter and Arthrobacter dominated in the catotelm. The functions of bacterial genera and species, identified by molecular biological methods, were described. A study of nitogen fixation, nitrogen decline and methanogenesis showed that bacteria were in a viable state and were able to remain active throughout the entire peat profile.

The features of the modern radioecological situation in forest (pine, spruce, birch) and fallow ecosystems in the contaminated (southern part) and background (northern part) territories of the Kaluga region are analyzed in this article. The density of soil contamination of the studied region by natural radionuclides (²²⁶Ra, ²³²Th, ⁴⁰K) corresponds to background levels, while technogenic radionuclide (¹³⁷Cs) significantly exceeds the background value (3 kBq/m²) and ranges from 60,8 to 273,8 kBq/m². Forest ecosystems (especially coniferous) are the most contaminated by ¹³⁷Cs, and fallow ones are the least contaminated. The density of ¹³⁷Cs soil contamination has decreased on average by more than 3 times compared to the initial period after fallouts (1986), but still significantly exceeds the permissible level (37 kBq/m²). The main contribution to the total specific activity of soils, as well as the power of the equivalent absorbed dose, is made by ¹³⁷Cs in the ecosystems of the contaminated areas, and by ⁴⁰K - in the ecosystems of background areas.

Soil is the basis of food systems at all levels. Preservation of the ecological functions of the soil cover, its condition in the territories newly introduced or withdrawn from agricultural use determines the degree and time of the onset of environmental risks, as well as risks and threats to food security.

The global value and cost of soil resources is increasing. Russia has a maximum soil cover of approximately 14,5 million km2—one sixth of the planetary. Soils, which are a unique national wealth and strategic resource, are underestimated. The volumes of applied agrochemicals are insufficient for the reproduction of fertility.

The achievement of food security indicators in the country and the export of food pro ducts occur due to non-reimbursable expenses of soil fertility reserves. There are no state documents that would clearly and unequivocally determine how many arable soils and agricultural land are needed to conduct modern agricultural production and fulfill tasks for sustain able development goals.

The composition of bottom sediment in the estuarine part of the Simmi River, a small tributary of the Amur River (Bolon State Nature Reserve, Russian Far East), was studied using X-ray fluorescence, electron microscopy, sedimentation analysis, and laser diffractometry. It is established that the formation of labile components in the bottom sediments (vivianite–clay microaggregates, gypsum microcrystals, and vaterite mesocrystals) is linked with effects of the pyrogenous factor in the Simmi River basin and the level regime of the main river. The formations are mobile due to their small size (<100 μm). The bottom deposits are primarily formed by such suspended sediments (particle size <100 μm), which is consistent with the lacustrine–alluvial genesis of the area. Two vivianite formation mechanisms have been identified in the bottom sediments in periods following fires, when the concentration of phosphate ions in the river water is elevated. Vivianite is formed on the surface of ferruginous–clay microaggregates, due to the reduction of Fe (III) in the presence of organic matter and on biological templates (organic residues and single-celled microorganisms).

In soils developing within a monolithic soilgeochemical catena, the composition of water-soluble macro-, microelements and anions has been studied. It has been shown that, as hydromorphism increases from eluvial to accumulative landscapes, the carbon and nitrogen contents naturally increase. The nature of the distribution of water-soluble forms of macro$ and microelements is due to bioaccumulative processes and features of eluvial-illuvial differentiation of soils. In the marginal parts of the watershed depression, the combination of eluvial$illuvial differentiation of the soil and intensive lateral removal in the spring determines the maximum leaching of the upper soil horizons. The use of cluster analysis confirms in the system of geochemical catena the relationship of genetic affiliation and soil position with the composition of water extracts.

In laboratory conditions, the decomposition of glyphosate with the formation of aminomethylphosphonic acid (AMPA) and its effect on the total abundance of bacteria and fungi, as well as the number of copies of genes encoding the enzymes C-P lyase of a-proteobacteria ( phnJ ), acid and alkaline phosphatase ( phoC and phoD ) and Fe-protein nitrogenase ( nifH ). It is shown that when applying glyphosate in recommended doses (5-10 mg/kg) 5-7% of the introduced herbicide is detected after 14 days, but when the dose is increased to 100 mg/kg, this value increases to 23%. Slowing down the rate of degradation of the herbicide appears only in the first week of incubation and is accompanied by a decrease in the number of copies of the phoC, phoD, nifH genes and an increase in the abundance of fungi. The obtained results indicate a predominant degradation of glyphosate with the C-P bond breaking and the formation of phosphates, as well as a possible inhibition of the nitrogen fixation process. It is shown that at an application dose of glyphosate 100 mg/kg, the accumulation of the first metabolite AMPA can occur during the degradation of the herbicide with a break in the C—N bond. Bioassay using wheat showed that when applying glyphosate at a dose of 100 mg/kg, there is an inhibition of plant development: the length of the roots and the biomass of the shoots reduced by 60 and 20% compared to the control, respectively. Based on the obtained data, it is proposed to use the reduction in the content of copies of the phoC gene and the growth of copies of ITS rRNA as indicators of the predominant decomposition of glyphosate through the sarcosin pathway. A reduction of copies of ITS rRNA gene by 40% or more can be used as an indicator of the possibility of AMPA accumulation during glyphosate degradation.

The laboratory study of the solid phase of salted peat by X-ray fluorescence analysis revealed the presence of some halogen-organic compounds. Cl-organic compounds were formed in one third of peat samples, while their share is small: 14-15% of the total Cl. On the contrary, Br-organic compounds are formed more often and Br_org proportion is higher: from 12 to 23% of total Br. Relatively weak development of halogenisation of the organic matter in salted peat bog is explained by the recovery conditions that prevent the synthesis of halogen-organic compounds. In X-ray diffraction analysis of peat ash, errors are possible, both due to the growth of minerals, and due to incomplete identification of the number of phases in high-ash peat samples. The second type of error can be corrected using data on the content of chlorine in peat by X-ray fluorescence analysis. In the characteristic of peat bog contamination, in addition to salt profiles in the solution, it is necessary to determine the number and composition of halogen-organic compounds, some of which have herbicide properties.

The process of natural remediation of oil-polluted and salt-polluted raised bogs of KhMAO - Yugra reclaimed 14-16 years ago is analyzed. In general, the revegetation is proceeding successfully, although mesophytic grasses sown during reclamation have almost completely fallen out of the grass stand. In salt-contaminated areas, there is a gradual desalination of peat soil, accompanied by a succession of halophytic (hemigalophytic) plant communities dominated by Calamagrostis epigeios, Eriophorum angustifolium and Phragmites australis with the participation of sphagnum and brown mosses, as well as liverworts. A characteristic feature of these habitats is the settlement of a number of rare protected species ( Heterogemma laxa, Thelypteris palustris, Triglochin maritimum ). In oil-polluted bogs, during the re-vegetation, hydrocarbons often flow from the underlying peat soil horizons to form the surface crust. At the same time, grass stands from Eriophorum angustifolium and some other species with powerful root systems are replacing grass-sedge-cotton grass communities. Sphagnum riparium and Warnstorfia fluitans play also a certain role in the overgrowth of crusted surfaces. Unsuccessful recovery is typical for hollows with difficult runoff in the case of salt-contaminated bogs and the most dry locations in the case of oil - contaminated ones.

Sewage sludge introduced 28 years ago in sod-podzolic sandy loam soils determines the increased content and mobility of Zn, Cd, Cu, and Ni compounds, and it is the most characteristic for Cd and Zn. The most polluted are the arable horizons of soils. The contaminated layer is within the arable horizon, which indicates on the low rate of heavy metals (HM) migration, which were introduced into the studied soils as part of SS. Heavy metals are washed out of soils with intrasoil runoff insignificantly. This is determined by their chemical properties: low solubility of their compounds, adsorption by mineral and organic components of soils, as well as neutral pH values of the soils themselves. Plants grown on contaminated soils are characterized by an increased content of HM, which varies in 5-7 times depending on the type of plants and their ability to accumulate HM.

The current study presented a genesis characterisation of iron-illuvial podzols formed on esker mainly coarse-grained deposits consisting of coarse and moderately coarse-grained sands including the gravel-pebble fractions with rubblestones. Under similar bio-climatic conditions, the iron-illuvial podzols on esker showed quantitative differences in composition and their properties from the iron-illuvial podzols formed on sandy moraines. The source of these differences were the relief and lithology of deposit genesis of uncommon structure of esker. The still commonly used description of fluvioglacial deposits, without their differentiation in esker as an inner-glacial deposit and periglacial deposits formed out of glacier range were insufficient in terms of a pedogenesis with special features in relief and sediments.

The features of the dynamics of the morphology and chemical properties of forest litter during post-agrogenic reforestation of arable land in the southern taiga subzone are studied. The relationship between the dynamics of the structure of litter with the floristic composition and the ecological-coenotic structure of the soil cover is shown. The increase in stocks, as well as the diversity of the structure and the degree of spatial variation of the main morphological indicators of litter as the regeneration of the stand has been established. Acidification and a decrease in the ash content of litter, as well as a decrease in the fraction of easily decomposed fractions, are adequately reflected in the composition of the soil cover, in which the role of species adapted for increased acidity and low content of nutrients in the substrate increases. After spruce enters the first tier, the spatial distribution of the structure, reserves, power, and fractional composition of litter is determined by the position in the tesser. In general, the course of succession, as well as the dynamics of the morphology and chemical properties of litter, indicates a decrease in the rate of circulation in biogeocenosis. The ecological scales of Ellenberg, Landolt, Tsyganov and Ramensky as applied to ground cover can serve as an important tool in analyzing the dynamics of forest litter in forest ecosystems.

For the first time, the ratio of large taxa and the genera spectrum in the prokaryotic complex of the rhizosphere soil under typical plants of bogs were revealed by high-performance sequencing. The dominance of acidobatheria and alpha-proteobacteria was established with a low proportion of other taxa (less than 10%). Among the 24 bacterial genera found, representatives of the phylums Acidobacteria and Actinobacteria, as well as the Alphaproteobacteria class, predominate. Common bacterial genera were identified in rhizosphere soil under plants and surface layers of peat. Representatives of most of these bacteria are adapted to grow in an acidic environment and at low temperatures. Their functioning is determined by the use of various sugars, polysaccharides, aromatic compounds, organic and amino acids. Bacteria of the genera Cytophaga and Acidothermus are capable of cellulose destruction, Occallatibacter - chitin, Nocardia - humic substances and lignin.

Some aspects of application of simulation modeling of radionuclide behavior in food chains of terrestrial ecosystems are discussed. The model of behavior of ¹³⁷Cs in the system of type soil-vegetation-herbivores-predators is described. The results of modeling, including the calculation of the dynamics of dose load on animals, are presented. It is shown that in the simplified “Chernobyl” scenario of the radiological situation, dose loads on herbivores are significantly lower than on predators. In general, in animals in the first 10 years, the main contribution to the dose load is made by external irradiation. Then the external and internal dose loads become approximately equal.

In closed soil conditions on tomato, cucumber and pepper cultures, the effectiveness of the integrated use of chicken compost, silicon fertilizer based on diatomite and the microbial preparation of the Bacillus amyloliquefasciens culture was evaluated. New technology allows you to get a crop increase of all high-quality vegetable crops. The studied agrochemical properties of gray forest medium loamy soil after harvesting did not deteriorate. In contrast to experiment options using traditional mineral fertilizers, the collected products fall under the definition of “organic” or with improved quality indicators, the so-called “green”. The resources of raw materials for the creation of nature-like innovative technologies of “green agrochemistry” are calculated. Now Russia produces about 310 million tons of organic animal waste, less than 70 million tons or 23% is used. The total content of only three plant nutrient elements (NPK) in the organic matter is 2,9 million tons of active substance. Their cost at current prices for mineral fertilizers exceeds 70 billion rubles. Perhaps the full useful use of organic resources in the system of measures for the “revitalization” of rural territories in terms of maintaining soil fertility and preventing “decarbonization”. This will reduce the negative impact of uncontrolled turnover of nitrogen and carboncontaining products on the components of the environment.

The composition of water-soluble organic matter (WSOM) of coniferous-deciduous, coniferous and moss litter was studied. Type of decay affects the composition of WSOM. Sphagnum litter contains less N and dissolved organic carbon (DOC), but more carbohydrates, the WSOM is characterized the lowest extinction coefficients Е₂₅₄. WSOM from mixed litter with a predominance of birch litter has a maximum content of N and a small amount of soluble phenolic (SP) substances. WSOM from litter of pine needles differ from the rest with a lower content of carbohydrates, the maximum amount of SP and hydrophobic fraction. All investigated WSOM are characterized by high rates of decomposition: half-decomposition time of their stable fractions is 2-4 months. WSOM from pine litter at pH ~ 6 are absorbed by the BF horizon of Podzol, since the concentration of DOC of 100 mg/l. Substances from birch-spruce litter in similar conditions adsorbed slightly.

Based on publications on the soils of the Northwest Pacific, particularly wide effect of climatic factor on soil formation associated with the influence of the ocean has been established. Together with the amount of liquid atmospheric precipitation, the regime and the intensity of their precipitation play an important role. Heat supply is determined not only by insolation, but also by the wind regime, as well as the presence of warm and cold currents. The scale of the pulsed contribution of sea water salts with sediments is related to the distance to the coastline. In additions, the ornithogenic factor acts on small islands. All this creates variants of soil formation specificity on the characterized islands.

Research of soil cover heterogeneity of Khibiny mountains within the Polar-Alpine Botanical Garden was carried out. Podzols and podburs occupy larger area in the garden (90%). Human-transformed soils are widely spread in the areas disturbed during the construction and introduction of plants. The soils of the garden are in the zone of influence of apatite-nepheline factories and metallurgical plants. As a result, in upper horizons there is a high content of some heavy metals and metalloids such as Ni, Cu, Pb, As, Zn, V, Sr.

We conducted soil zoological studies on the Southern coast of Crimea in the Nikitsky botanical garden and in the natural reserve “Cape Martian”. We found 22 taxonomic groups of large invertebrate soil animals, whose number was up to 1000 spec/m², and biomass - up to 25 g/m², in the artificial stratozems of the garden and in the natural red-colored soils of the reserve. The territory of the Nikitsky garden is characterized by a greater biomass and taxonomic diversity of the soil macrofauna than Cape Martian, but the structure of the communities of the two territories have similarities. Higher biodiversity and biomass in the garden are explained by increased soil moisture due to sprinkling and the mosaic distribution of vegetation in the arboretum. Both territories are characterized by a large internal heterogeneity of the soil population, which is due to the variability of soil properties, which is determined by the differences in the artificial soils of the Nikitsky garden and the gulley erosion of the soils of Cape Martian. These factors, together with the diversity of vegetation cover, affect the heterogeneity of the macrofauna distribution and provide high biological b-diversity of the territory.

The article considers agrochemical factors for cultivation of medicinal plants with focus on biomass increase primarily due to a role of nitrogen and zinc and change in the fractional composition and concentration of carotenoids in Calendula officinalis L. A two-year vegetative experiment with calendula of Kalta variety was carried out. Effects of Zn and Zn supplemented with N intake on morphological changes, blooming and reproduction were studied. Intake of nutrients into above-ground plant parts was studied utilizing a variety of chemical methods. The quantitative and qualitative composition of carotenoids by HPLC was established. The calculated value of the accumulation of carotenoids by plants for the entire vegetation period was performed. Data were subjected to analysis of variance (ANOVA) and means were separated by Duncan multiple range test at P < 0,05 significant level. Factors selected by us in the growing experiment, formed contrasting options which allowed to determine the most effective way to grow medicinal crops on chernozem soil.

The mineralogical composition of fraction of more then 0,1 mm of podzolic soils of the Kostroma region was studied. One of the debatable versions of finding the boundary between the glacial deposits of the Moscow and Dnieper ages is confirmed. Signs of destructions of minerals are established, this indicates the role of this process in providing mineral elements of the subsurface, which formed on weathered glacial deposits.

The study of the mineralogical composition of sand (0,25-0,05 mm) and coarse silt (0,05-0,01 mm) fractions revealed a significant lithological heterogeneity of soil forming material on the territory of the Zvenigorod biostation. The predominance of ore minerals in the heavy fractions (up to 42% of the grains) and, to a lesser extent, hornblende and biotite, explains the ironing (significant presence of iron oxides, hydroxides) of the profiles and the brown color of sandy loam soils. This feature, along with the insignificant presence of the clay fraction, admit us to classify texturally undifferentiated soils as ferric-metamorphic soils, and more differentiated - as eluvial soils.

The composition of water extracts of the soil, litter and land litter was studied for the conditions of the nesting places of the gray heron and the control plots in the zone of distribution of gray forest soils of the broad-leaved ecosystems of the Tula area. It has been established that the entry of bird excreta leads to an almost universal degradation of land cover, the formation of specific litters, with a significant influx of large tree litter, which is associated with the nest building process. It is shown that the upper horizons of gray forest soil, litter and litter in nesting conditions are characterized by an increased content of such elements as calcium, potassium and magnesium, and among trace elements - copper, zinc and strontium. Among the anions in the soils and litters of bird nesting sites, an increase in the content of nitrates, phosphates and chlorine was found.

The properties of representative soil profiles of podzols included in the database of the Unified State Register of Soil Resources of Russia are considered. As a result of processing and analysis of the data array (53 measured profiles), the ranges of values of a number of parameters were adjusted. It was found that in most cases the properties of podzols had a wider range of values compared with the estimated profiles given in the literature (thickness of illuvial horizon, humus content in eluvial horizon), at the same time, the range of values of the humus content for the illuvial horizon was narrower. The specificity of the podzols of individual regions obtained by combining of soil provinces of the Map of soil-ecological zoning is revealed. Regularities can be traced in the geography of the profile thickness of these soils, the content of humus and its profile distribution. In Siberian regions humus prevails in the eluvial soil horizon, in the European territory of the country and in Primorye - in the illuvial horizon.

In hydromorphic soils are important not only sustainable Fe-minerals, defined traditionally in dried soil, but also unstable Fe-minerals, changing the colors of the clay after extracting the sample fr om the soil, as well as — weakening gley signs in the dry season. New indicators are offered for the additional characteristic of Fe-minerals. The first is that it characterizes the interaction of active Fe-minerals with colloids, it is index I: I = CEC/Fe (free), wh ere CEC is the cation exchange capacity. The second indicator is the change in the gley color after drying, assessed by the change in the redness Да*. In Fe-enriched, reduced gley Gr with a low index value (/0,1) and a strong increase Aa* ~ 9 after drying, the green rust is transformed into a brown lepidocrocite. During the humidity decrease, the transition of the reduction gley to the oxidized gley is accompanied by a change in the composition of the green rust: the transformation of fougerite into a trebeurdendite: Fe-ephemera with a higher degree of Fe oxidation and the growth of Да* ~ 3. When oxidized gley Go with the index I = 2—8 is dried, the slow Да* growth is caused by the inhibition of Fe-hydroxide crystallization by colloids. In the “de-ironed” gley Gdf with a high value the index 1= 6—27, the lack of red growth (a* « 0) on drying, is probably due to the Fe clay minerals inertia.

The paper presents a comparative analysis of the structural and functional characteristics of the microbial communities of the gray forest soil of fallow and intensively cultivated areas. Long-term anthropogenic impact with massive annual mineral fertilization when growing a monoculture of potatoes has led to the degradation of the soil microbial system. A catastrophic decrease in the functional potential of the microbial system (environmental services) is shown using eco-exergy as a thermodynamic indicator of the “health” of the soil.

The texture of bottom sediments of the Simmy River and its tributaries in the area of the “Bolon'sky” reserve (Khabarovskiy region, Far East) was studied with methods of laser diffractometry, sedimentation and electron microscopic analysis. It was found out that the texture of Simmy sediments in downstream is characterized by the accumulation of fine sand, which corresponds to alluvial-lake genesis of the studied area. In the wellhead part of river sediments are formed mainly by suspended sediments with a predominance of the clay fraction. This is due to the impact of the floodplain Bolon Lake, which level fluctuations correspond to changes in the level of water in the Amur River. It is shown that coagulation and deposition of suspended particles with low content of organic matter (< 1%) leads to the formation of volumetric aggregated, dense and viscous sediments. The high content of organic matter in sediments (> 6%, the Kirpy River, the tributary of the Simmy River) leads to the “nodal” differentiation of spatial structures and to the formation of porous microaggregates.

The taxonomy of peat soils is not currently given more attention, especially with regard to taxonomic units in the species rank. The procedure of diagnostics of 51 soil profiles in the various oligotrophic mire types in the Numto nature Park (north taiga subzone of West Siberia) allows to make some proposals to improve the existing soil classification. These ones are: 1) to limit the peat horizon thickness in the peat-gleyzem type to 30 cm; 2) to divide the peat-gleyzem type by the trophic status into oligotropic and eutrophic subtypes; 3) to expand the list of taxa, determined by the botanical composition of peat, by means of the division of soil species into subspecies on the basis of classifications of peat and peat deposits; 4) to use current vegetation as one of the main diagnostic (indicative) criteria in determining the soil type in mires; 5) in order to determine the variety of peat soil it is suggested to use the degree of decomposition of the peat layer underlying the peat soil. The article draws attention to the difficulties in determining the classification position of soils of frozen large mounds in palsa bogs and proposes alternative solutions to this problem.

We discuss the dynamics of the snow cover and its composition for the period 2013-2018 is shown that the annual dynamics of the snow cover is characterized by the alternation of high and low values. Thus, the highest values were typical for the winter of 2012/2013, followed by a decrease in 2013/2014. The leading role in the distribution of snow cover belongs to the position of the elementary landscape within the geochemical landscape. In all years of research, the water equivalent of snow cover is characterized by bicarbonate-calcium composition. The content of micro components in General is in the same order with the results given for the South taiga landscapes. Some excess of individual components in the composition of snow water in comparison with Meshchersk and Baikal landscapes, taken as a background, due to the proximity of the studied geochemical landscape and the main road M-10 (Moscow-St. Petersburg). It is assumed that the relatively high content of calcium in the snow water of the superaqueous landscape is associated with its possible arrival from the surface of meadowmarsh carbonate soils, boiling from the surface. Sulfate ion has been found to play a leading role in the diagnosis of atmogeochemical pollution, which is partially established for the studied landscapes.

The resistance to mineralization of water soluble organic matter (WSOM) extracted from a litter of Podzol is increased upon the interaction with the mineral horizons. Both the fraction of WSOM susceptible to mineralization and the average rate of decomposition decrease after the passage through E-horizon, by 2-3 times respectively, in comparison with the values obtained for the initial WSOM. Sorption in the BF horizon gives extra stability to the incoming organic matter. The relative content of mineralized carbon is reduced to 2% (by 8 times). In natural soils sorbed organic matter can be even more resistant to the mineralization, due to lower temperatures and less biological activity, so it can be considered as the basis for the formation of a humus storage. Taking into account the calculated rate of mineralization, the accumulation of the organic carbon in the BF horizon due to WSOM sorption, may range up to 13,5/100 g per year, but this value depends on the concentration of organic substances in soil solutions, hydrological regime and other factors.

The influence of anthropogenic activity on the quality of urban alluvial soils, the conditions of growth and the state of tree plantations is estimated. The level of negative consequences for natural components correlates with the degree of human exposure. In the profile of soils moisture decreases, humus content varies in different directions, pH of waters and electrical conductivity increase. Densification of soils and inhibition of biological activity are noted in the surface horizons. The coefficient of the ecological state of soils decreases by 6-24% compared to the optimum conditions. The correlation analysis showed the presence of a significant weak matching between vegetation state and soil quality (Spearman's coefficient is -0,53).

A comparative description of the structural and functional organization of plant litter and forest floor in the course of natural postagrogenic reforestation in the chronory series of ecosystems for 12, 40 and 100 years is given. As the age of the stand increases, an increase in the total reserves and diversity of litter types, a decrease in the proportion of easily decomposable components, and a decrease in their pH and ash content are found. The change of ground cover is accompanied by the replacement of grass cover with grass-shrub, which indicates a decrease in the trophicity of ecosystems. The characteristics of the litter are adequately reflected by the composition of the ground cover. As the stand is restored, a regular decrease in the decomposition intensity of the ground detritus and the speed of the biological cycle occurs. Spatial differentiation of litter types serves as a trigger for the subsequent divergence of soil organic profiles.

Speciation of ²²⁶Ra and ²³²Th in sod-podzolic-gley concretionary soil are studied. It has been shown that with periodic overmoistening by surface waters and alternation of reducing and oxidizing conditions, the mobility and availability to plants of ²²⁶Ra is substantially higher than ²³²Th. The sum of fractions available to plants (water-soluble and exchangeable) and mobile (water-soluble, exchangeable and mobile) of ²²⁶Ra is 2-10 times higher than ²³²Th. Segregated ferruginous nodules formed in the eluvial horizons of this soil have a weak effect on the mobility of ²²⁶Ra, but significantly reduce the mobility of ²³²Th, much of which is substantially fixed inside the crystal lattices of newly formed minerals.