Moscow University Soil Studies Bulletin. 2026. 3.

The wide species diversity of chitinolytic actinomycetes producing secondary metabolites and hydrolytic enzymes offers opportunities for effective soil biocontrol aimed at protecting plants from phytopathogens and preserving soil biodiversity. This study examined the chitinolytic potential of five soil actinomycete strains from the genus Streptomyces(S. flavovirens TT, S. sindenensis TK, S. baarnensis assi-23TB, S. anulatus TG, and S. xiamenensis TB) through integrated analytical and molecular biological approaches.The study demonstrated that the fundamental mechanism of Streptomycesstrain adaptation to chitin utilization is the targeted induction of functional chitinase genes.We identified distinct genome activation strategies and observed that high genetic activity leads to a robust physiological response, including active biomass accumulation and CO₂ emission. These findings confirm the high competitiveness of the investigated strains under conditions of limited access to readily available carbon and nitrogen sources. The study elucidated the interaction of the target strain Streptomyces baarnensis assi-23TB (VKPM Ac-2228) with two specific phytopathogens in both in vitro and in planta systems, using wheat seedlings (Triticum aestivum L. cv. Arkhat) and microclonal potato plants (Solanum tuberosum L. cv. Romano) as host models. A comparative analysis was performed to correlate the metabolic capabilities of S. baarnensis assi-23TB, as theoretically predicted by bioinformatic tools (antiSMASH, PATRIC), with its actual phenotypic metabolite production. The strain exhibited significant chitinolytic activity. Our analysis revealed dibutyl phthalate (DBP) to be a constitutive secondary metabolite responsible for the baseline antimicrobial activity.Notably, several predicted biosynthetic gene clusters (10-epi-HSAF, keivymicin, alkylresorcinol, desferrioxamine B, naringenin, and zeatin) remained in a "silent" state under the experimental conditions. We found that the S. baarnensis exometabolome strictly depends on the presence of the host plant and specific pathogens (Fusarium graminearum and Phytophthora infestans). The association with wheat exclusively triggers the synthesis of the phytostimulant putrescine and energy metabolism regulators, such as lactic and succinic acids. This symbiotic system also drives the production of amino acids, sugars, and myo-inositol.The study experimentally confirms the multifunctionality of the Streptomyces baarnensis assi-23TB strain, which integrates direct enzymatic lysis of pathogens with the biochemical stimulation of plant growth and adaptive responses

A comprehensive study of the mycobiota in eutrophic peat soils under forests was conducted: birch forest, mixed forest (Tomsk District, Tomsk Region), black alder forest, and pine forest (Zapadnodvinsky District, Tver Region). The litter (layers L and F) and eutrophic peat horizon (TE: 0–20, 20–30, and 30–50 cm) were analyzed during the summer and autumn of 2021. The stocks and structure of fungal biomass were studied using luminescent microscopy, and the number of cultivated representatives was determined using the sowing method. Fungi were identified on the basis of phenotypical characteristics and the results of 26S rRNA nucleotide sequence sequencing. It was found that in the litter of the studied soils, fungal biomass ranged from 2 to 30 mg∙g‒1, fungal biomass stocks ranged from 28 to 189 g∙m–2, and fungal biomass carbon stocks ranged from 139 to 945 kgC∙ha‒1. In the eutrophic peat horizon, they ranged from 0,4 to 19,4 mg∙g–1, from 52 to 622 g∙m–2, and from 262 to 3110 kgC∙ha‒1, respectively. All indicators of fungal abundance increased from summer to autumn. The contribution of litter to fungal biomass reserves was more significant in soils under deciduous forests — up to 67%, while in soils under coniferous forests it did not exceed 10%. Fungal biomass in the studied horizons was mainly represented by mycelium, with spores accounting for 1 to 40%.The number of cultivated fungi in the studied soils ranged from 103 to 106 CFUg‒1 and was 2–3 orders of magnitude higher in litter than in TE. Seasonal changes in the number of micromycetes were detected mainly in litter (summer values exceeded autumn values by 1–2 orders of magnitude). Over two seasons, 85 species of micromycetes from 46 genera, 27 families, 15 orders, 7 classes, and 2 divisions (Mucoromycota and Ascomycota) were isolated from the studied soils.Representatives of the Ascomycota division predominated, accounting for 89% of the total species composition. In soil microfungal communities, fungi of the Penicillium and/or Trichoderma genera dominated or were frequently encountered, but the vast majority of representatives of other genera were characterized as rare and incidental. In litter, the Shannon index ranged from 0,78 to 2,32, and in TE from 0,31 to 2,55. In autumn,as rule, a decrease was observed in almost all soil horizons.The species similarity of the communities of cultivated fungi (Ks) of the studied soils varied in the range of 0.42–0.56, and between horizons reaches 0.70.

The article presents the results of the research of the prokaryotic complex associated with plants in blackalder-meadowsweeteutrophic swamp (Zapadnodvinskiy District, Tver Region). The phylloplane (leaves, stems), rhizoplane (roots), and rhizosphere soil of six plants, namely Calla palūstris L., Filipendula ulmaria (L.) Maxim., Carex cespitosa L., Urtica dioica L., Athyrium filix-femina (L.) Roth ex Mert.and Scirpus sylvaticus L., were analyzed. The abundance of unicellular and mycelial bacteria in plant and soil substrates was determined by luminescent microscopy and culture method. The taxonomic composition of cultured bacteria was assessed on the basis of phenotypic characteristics and the results of 16S rRNA nucleotide sequence analysis. It was found that the dimensionless universal characteristic of prokaryotic communities — the K index (the ratio of bacteria counts based on microscopy and culture data) —and the alpha diversity index (the Shannon index)— increase in the order phylloplan<rhizoplan< rhizosphere soil. Representatives of 4 phyla, 23 genera, and 63 species of cultivated bacteria, 27 of which are mycelial. were isolated and diagnosed from the analyzed substrates. It was determined that Carexmicroloci were characterized by maximum abundance and diversity of bacteria. Filipendulamicroloci are promising targets for the isolation of streptomycetes with antagonistic potential against phytopathogenic fungi that cause various diseases in agricultural plants. It was shown that rhizosphere soil under plants in blackalder-meadowsweeteutrophic swamps is a substrate for the isolation of bacteria of the genus Stenotrophomonas, which are used as effective bioinoculants to stimulate plant growth and as microbiological agents for biocontrol.

A comprehensive study of prokaryotic communities (microbiomes) of bacterial mats and snottites from the karst cave Sheki-Kh’ekh was carried out for the first time, with comparison to cave soil-like bodies (SLBs) from the Muhammed-Kh’ekh cave and adjacent brown forest soil. The total abundance of bacterial cells in mats and snottites varied within a relatively narrow range, from 0.26 to 0.35 billion cells per mL, reaching maximum values in floating bacterial mats and minimum values in snottites. In soil-like bodies, the total bacterial abundance was 0.28 billion cells per g. Actinomycete mycelium was detected in all cave samples, with the highest values observed in floating bacterial mats and the lowest in shoreline bacterial mats.
Metabarcoding analysis (16S rRNA gene sequencing) revealed high taxonomic diversity of prokaryotic communities across the studied substrates. The greatest diversity was recorded in floating bacterial mats (25 phyla and 74 genera). In all cave substrates, the dominant phyla were Pseudomonadota and Bacillota, while Bacteroidota also dominated in floating bacterial mats. Lower relative abundances were observed for Actinomycetota, Verrucomicrobiota, Chloroflexota, Chlorobiota, and Thermodesulfobacteriota. Eleven bacterial phyla were shared between soil and floating bacterial mats: Pseudomonadota,Bacillota,Bacteroidota,Verrucomicrobiota,Chlorobiota,Chloroflexota,Actinomycetota,Acidobacteriota,Cyanobacteriota,Planctomycetota, and Armatimonadota, along with two candidate phyla, Sumerlaeota and Hydrogenedentes. Two archaeal phyla, Woesearchaeota and Nanoarchaeota, were detected in bacterial mats.
A total of 191 bacterial genera were identified across all studied substrates. Only 12 genera were common to bacterial mats and soil: Brevundimonas,Devosia, Flavobacterium,Luteolibacter, Paenibacillus,Paenisporosarcina,Pseudarthrobacter, Pseudomonas,Rhodanobacter,Sphingomonas, Sumerlaea, and Thermomonas. A distinctive feature of floating bacterial mat communities was the high representation of genera involved in sulfur cycling processes. Functional profiling revealed the predominance of sulfur- and iron-cycle-related functions in bacterial mats, whereas nitrogen-cycle-related functions and chemoheterotrophy prevailed in soil communities.
This study significantly expands current knowledge of the taxonomic composition of prokaryotic communities inhabiting bacterial mats and snottites of sulfidic caves in the Chechen Republic. The presence of bacterial genera involved in sulfur and iron transformation processes highlights their ecological significance. The results obtained on the diversity of prokaryotic communities in mats, snottites, and soil-like bodies are of interest for understanding ecosystem functioning and for the targeted search of strains with valuable biotechnological properties.

Actinomycetes are key functional group of soil microorganisms that play a critical role in organic matter decomposition and the regulation of biogeochemical cycles in tropical ecosystems. This study provides a comprehensive analysis of actinomycete community structure and the physiological traits of cultivable strains in soils and litter from two protected areas in Southern Vietnam: Bidoup and Cat Tien Nature Reserves. We combined culture-based and molecular approaches, including quantification of cultivable actinomycetes, assessment of strain tolerance to abiotic stresses, evaluation of enzymatic activities, and high-throughput 16S rRNA gene sequencing to determine the taxonomic composition of prokaryotic communities. Actinobacteria were found to be dominant across soils, with clear differences between soils and litter. Litter communities were relatively uniform across elevations, whereas soil communities displayed pronounced variation. Cultured Streptomyces strains exhibited broad stress tolerance and high enzymatic activity, underscoring their ecological significance in tropical soil functioning.

For the first time, a comprehensive study of the biological activity of microbial communities in protected tropical ecosystems of Vietnam has been conducted using the example of four types of substrates: mineral soils and associated plant litter, rhizospheric soil, and specific soil-like formations —“suspended” soils in baskets of epiphytic ferns. It is shown that suspended soils and plant litter are characterized by 3‒5 times higher microbial biomass (up to 1.44 mg•g⁻1), as well as significantly more intensive processes of carbon dioxide emission, nitrogen fixation and denitrification compared with mineral soil horizons. The revealed high biological activity of these substrates correlates with an extremely high content of organic carbon (up to 51.4%) and less acidic pH values. For the first time, methane emissions were quantified for this territory, showing maximum values in the upper soil layer (up to 173 ng CH4•g‒1•day–1) and a negative correlation with altitude (p=0.0001). The data obtained make it possible to identify plant litter and epiphytic “suspended” soils as key loci of biogeochemical cycles of nitrogen and carbon in the tropical forests of Vietnam.

Abstract.This study presents the findings of an investigation into the abundance and morphological diversity of bacteriophages in samples of urban soils (Urbanozem and Replantozem) and atmospheric dustfall (ADF) collected across Moscow from sites with varying degrees of anthropogenic impact. Using direct epifluorescence microscopy with the SYBR Gold stain, it was demonstrated that bacteriophage abundance (virus-like particles, VLPs) was higher in soils (1.12–2.1010⁹ VLPg‒1) than in ADF (0.42–0.6410⁹ VLPg‒1), correlating with total bacterial counts. Through enrichment culture techniques followed by biological purification, a collection of bacteriophages (coliphages) infecting Escherichia coli strains with different cell surface compositions (different O-antigen types) was obtained. Transmission electron microscopy revealed that some of the isolated coliphages belong to the class Caudoviricetes (tailed phages) and are characterized by Siphoviridae (possessing long, non-contractile tails) and Podoviridae (possessing short tails) morphotypes. The obtained data underscore the significant role of bacteriophages in the functioning of microbial communities within urban ecosystems and their potential for use in the bioremediation of urban soils.

The aim of this study was to investigate the patterns of plant diversity formation on extensive green roofs in a continental climate and the role of adjacent lawns as sources of colonizing species. In 2024, extensive green roofs were established in Moscow and Yekaterinburg on two substrate types (regional and universal) at two depths (15 and 25 cm), with 3 replicates per treatment. In May 2025, regional plant species (seedlings) were planted: in Moscow —Festuca glauca Vill., Thymus serpyllum L., Achillea millefolium L.; in Yekaterinburg —Aster alpinus L., Festuca glauca Vill., Festuca rubra L., Origanum vulgareL., Dianthus acicularisFisch. ex Ledeb., Veronica spicata L. Weeds were not removed. In September 2025, species were recorded, and community similarity (Jaccard coefficient, Bray – Curtis index) was measured between lawns and roofs, as well as within roofs between different treatments, together with alpha diversity (Shannon index H', Simpson index 1-D, and evenness). In parallel, the species composition of adjacent lawns was surveyed. In total, 50–60% of roof species were also present on lawns; the Jaccard coefficient ranged from 0.14 to 0.32; H' for roofs ranged from 1.08 to 2.08 (13–15 species). Unique species of Moscow roofs were dominated by R/CR strategies (Lactuca saligna L., Lactuca serriola L., Amaranthus retroflexus L., Portulaca oleracea L., Digitariasanguinalis(L.) Scop., Gnaphalium uliginosum L., Iva xanthiifolia Nutt., Acalypha australis L., Euphorbia virgataWaldst. & Kit., Lipandrapolysperma(L.) S. Fuentes, Uotila & Borsch, Epilobium obscurumSchreb., Myosotis sparsifloraJ.C.Mikan ex Pohl, Veronica longifolia L., Festuca arundinaceaSchreb.), whereas in Yekaterinburg C/CR species dominated (Trifolium arvense L., Medicago falcata L., Lolium perenne L., Rumex obtusifolius L., Viola tricolor L., Galiumspurium L., Arenaria serpyllifolia L., Setariaviridis(L.) P.Beauv., Rudbeckia hirta L.). High spatial heterogeneity in similarity and diversity indices was observed for Moscow roofs, whereas substrate type and depth had no significant effect. Thus, lawns were the main source of spontaneous colonizers of green roofs. Vegetation succession during the first year on green roofs went through an R/CR stage, probably under the dominant influence of climatic factors.

Theresults of studyingmicroarthropodcomplexesinsoilsunderdeciduouswoodyvegetation of fourrecreationalareas of Moscowwithin the CentralandWesternadministrativedistricts: the garden of the manorMuseum of L.N. TolstoyinKhamovniki, the BotanicalGarden of Moscow State UniversityonVorobyovyGory, the VorobyovyGoryNatureReserve, the TroparevskyLandscape Reserve are presented.Soil and zoologicalwork was carried out in2018,2019and2024. Dark humus stratozem, gray humus surface residual carbonate, gray humus (turf) and other soils were studied among the soils.
17taxa of smallarthropods were found,from10to14in the soils of most of the studiedsites.Ticks(Acari)predominatedeverywhere,accounting for at least53%of the totalnumber of microarthropods. The share of Collembolavariedfrom21%to45%. The number of microarthropodssometimesreachedvaluesup to 118,000specimensm‒2,whichisseveraltimes higher than the knowndatafornaturaldeciduousforests near Moscow.Aplot has been allocated in the centralpart of Moscowwith a lowpopulationonaveragenomore than 20,000specimensm‒2,where the destruction of leaflitter,frequentmechanicaldisturbance of the surfacehorizons of the soilandothertypes of impacts have ledto a steadydecrease in the numberandcomposition of microarthropodcomplexes.Thelowestvalue of the soilbiologicalqualityindex(QBS=55) was recorded at thesamesite. The resultsobtainedconfirmthatindicatorssuchas the number(populationdensity),composition of microarthropods,andthesoilbiologicalqualityindex(QBS)can be usedasindicators for assessing the state of soils.

We obtained data on the number of saprotrophic bacteria and the structure of bacterial complexes of cultivated bacteria of the soil of the fallow field, the material of anthills located in the field under study, and ants of the species Lasius niger and Lasius flavus, which are dominant species in this fallow field. It has been established that ants of two closely related species from the genus Lasius differ significantly in the number and composition of the cultivated bacteria associated with them, and have a different effect on the microbiocenosis of the soils they inhabit. A high similarity of bacterial complexes of L.niger ants and the material of their nests was shown, at the same time, such a pattern was not revealed for L. flavus. It has been established that the structural components of anthills differ in the number and composition of cultivated bacteria. It has been shown that in general, anthills are loci of increased abundance and higher bacterial diversity compared to control soils, which can be traced not only in the surface soil layer. It has been found that the nesting activity of ants promotes the redistribution of microorganisms down the profile, as a result of which the increased biodiversity of microorganisms is maintained at a greater depth than in the control. To a greater extent, this phenomenon is characteristic of soil-dwelling ants L. flavus. In anthills, an increased number of fertility-improving bacteria with high biotechnological potential, such as Pseudomonas koreensis, capable of fixing atmospheric nitrogen, and Paenibacilluschitinolyticus, showing chitinolytic activity, was found compared to control. According to the results of additional studies, representatives of Agrobacterium radiobacter, not identified by direct inoculation, were identified from the accumulation culture on Ashby's nutrient medium. With the help of genome-wide sequencing, several species of bacteria were identified that were not determined by mass spectrometry.

Yu. V. Zakalyukina, A. R. Zaytsev, A. A. Belov, Yu. A. Zavgorodnyaya, M. V. Golichenkov The study assessed the impact of the nest-building activity of Camponotusvagus ants on the biological activity of microbial communities in the nest material compared to the surrounding soil. The objects of the study were samples from the aboveground and underground parts of theblack carpenter’s nest, built in a dead wood of Pinus sylvestris L., collected in the Ryazan region in a pine forest on humic arenosols. Using optical and scanning electron microscopy, a specific "nest material" was characterized, consisting of wood, plant debris and sand, densely woven with fungal mycelium, in which the presence of actinomycetes and unicellular bacteria forming associations was also shown. Comparative analysis of the elemental composition (C, N, P, S) demonstrated that this woody material is significantly enriched in all biophilic nutrients, and the C:N ratio in the nest material is effectively reduced compared to dead pine wood. The microbial community of the "nest material" was characterized by an increased intensity of processes involved in the nitrogen and carbon cycles (potential activity of nitrogen fixation, denitrification, CO₂ emission, and CH₄ production) compared to the microbial communities of the soil part of the nest and the control soil. Thus, during their nest-building activity in pine forests formed on poor sandy soils, Camponotusvagus ants intensify wood decomposition and thereby create unique habitats ("hotspots") with elevated biological activity. This underscores the important ecosystem function of carpenter ants. There are grounds to suggest possible symbiotic relationships between the ants and the mycelial microorganisms that form the so-called "nest material".

Despite the significant role of the black garden ant (Lasius niger) in soil formation processes, the seasonal dynamics of microbial biomass in its nests and adjacent urban soils remains poorly understood. The relevance of this study is related to the need to assess the contribution of L. niger to the biological activity of soils under anthropogenic stress. The study is aimed at analyzing the dynamics of microbial biomass and its activity in the nests of L. niger ants and the surrounding urban soils during the growing season. In this work, methods of luminescent microscopy were used to estimate the total number of microorganisms and the dynamics of its changes during the growing season, as well as the method of multisubstrate testing to determine the functional diversity of microbial communities and methods of mathematical statistics. In the studied urban soils, there was a significant decrease in the proportion of fungal and an increase in the proportion of bacterial components in microbial biomass compared to zonal soils. The predominance of fungal cells (spores and yeast cells) was recorded in the fungal biomass, while their maximum number and minimum biomass of fungal mycelium were noted at the end of the growing season. The effect of L. niger ants on the composition of microbial biomass in the soil was manifested in an increase in the length of the fungal mycelium and bacterial biomass reserves compared with the control. The influence of anthropogenic stress on the structure of microbial biomass in anthills is more pronounced than in control soils. The nesting activity of ants had a significant impact on the functional parameters of microbial communities formed in the soil. The material of the anthills showed a change in the spectrum of organic substrates consumed by the microbial complex and the rate of their consumption compared to the control soils. It was found that microbial communities less climactic than in the soil form in anthills in areas with the lowest anthropogenic load, which may be due to a more intense foraging activity of insects in these areas. It should be noted that the stability index (d) of microbial complexes in anthills showed less variability during the growing season than in the same indicator in soils.

The article presents the results of an 18-month field experiment assessing the impact of 11 mulching substrates used in urban soils on a range of physical, chemical, and biological properties. The following substrates were studied: serpentine, marble, volcanic tuff, foam glass, coconut chips, painted and unpainted pine chips, large and small fractions of larch bark, and large and small fractions of pine bark. The substrates used were shown to have no negative impact on pH, total carbon (Corg) content, or its water-soluble forms (Cws), and no effect of the substrates on soil bulk density. The use of mulching substrates on urban soils contributed to an increase in the biological activity of the soil prokaryotic complex and a decrease in the number of sanitary-indicator and potentially pathogenic bacteria (Escherichia coli) in the soil, which reduces potential risks to the health of the urban population. The most favorable soil properties, based on the totality of the studied parameters, are formed under organic mulching substrates consisting of fine-sized particles, coconut chips and larch bark. An increase in the content of microscopic fungi in the upper horizon of urban soil under a 5-cm-thick mulch layer was detected. This may pose potential risks to human health due to the allergenic and potentially pathogenic properties of some soil micromycetes and requires further research. The obtained results allow us to recommend mulching urban soils with organic substrates not only for decorative purposes but also to enhance biological activity and, consequently, improve the biological condition of soils in anthropogenically transformed conditions.

The lithological matrix of surface soil profiles in the northern Mologo-Sheksna Lowland, within the wide valley of the lower Sheksna River and the foothills of the Andoga Ridge, reveals the final stage of Late Pleistocene aeolian sedimentation, reflected in the composition of the surface soils. Morphological and genetic analysis of soil profiles at the macro- and microlevels, supported by analytical characteristics and particle size distribution data, allowed us to identify and substantiate at the regional level a series of four contiguous layers of different ages and lithologically contrasting features. The base of the studied soil profiles is the Moscow glacial basal till (layer I, which displays consistent features of Mikulino pedogenesis (Bt horizons). The final stage of loess sedimentation in the upper part of the soil profiles during the Late Glacial (layer III) has been dated using the OSL method and falls within the range of 17,000–22,000 years ago. Layer II, represented by gravelly-sandy sediments in the middle part of the profiles of several of the studied soils, reflects a local stage of active sedimentation after the Mikulino period, during which the upper part of the glacial till may have been truncated (eroded). Thus, the studied soils represent a pedocomplex formed in the Late Pleistocene (a 150,000-year macrocycle). Identifying the final stage of loess sedimentation in the Late Glacial will allow us to assess the contribution of soil and lithological processes to the formation of the profile of loamy soddy-podzolic soils. Establishing the final stage of eolian sedimentation in the Late Glacial is also of great importance for paleogeography, as it reflects the impact of the global climatic rhythm at the Late Pleistocene-Holocene boundary on the modern landscape. The mantling of the Sheksna River valley by glacial basal till confirms V.V. Dokuchaev's (1877) concept of the role of glaciations in the structure of river valleys on the Russian Plain. The terrace levels in the studied areas represent ancient basement steps and do not belong to the modern river valley.

Thermal diffusivity of typical chernozems from Kursk region collected under a four-year-old fallow land, a fifteen-year-old fallow land, and a 46-year-old shelterbelt was studied. Undisturbed soil samples were cut vertically using thin-walled metal cylinders 7 cm high and 5 cm in diameter. Three replicates were collected for each depth. Thermal diffusivity was measured using a laboratory steady-state method, pre-saturating the samples with capillary feeding on a sand substrate and then drying the samples step by step to an air-dry state. The range of soil moisture content in the studied samples during laboratory measurements was from 0,03 cm3•cm–3 to 0,55 cm³cm–3. The bulk density of the samples varied from 0,85 g•cm–3 to 1,42 gcm–3, the organic carbon content changed from 2,1 to 3,9%. Thermal diffusivity of the studied horizons varied within the range of 1,35–4,03•10–7 m2s–1 under a four–year–old fallow, 1,06–4,28•10–7 m2s–1under a fifteen–year–old fallow, and 0,93–2,89•10–7 m2s–1under the shelterbelt. The correlation coefficient between the maximum value of thermal diffusivity and the sample bulk density was 0,61, and between the maximum value of thermal diffusivity and the organic carbon content it was –0.59. The dependences of thermal diffusivity vs. moisture content in most cases had the form of a curve with a slightly pronounced maximum in the range of high moisture contents and a section of almost unchanging thermal diffusivity in the range of moisture contentslower than 0,10 cm³•cm-3. Samples from the upper part of the former arable horizon under a fifteen-year-old fallow stood out in relation to the others; for these samples, the dependences of thermal diffusivity vs. moisture content had a pronounced S-shaped form, with an unusually long flat section in the moisture content range from 0,03 to 0,20 cm3 cm–3 and a sharp increase of thermal diffusivity in the moisture content range of 0,20–0,30 cm3 cm–3. A comparison of the results with previously obtained data for virgin land and arable land showed that in the series “virgin land – arable land – four-year-old fallow” the thermal diffusivity of the topsoil increases, while in the series “four-year-old fallow – fifteen-year-old fallow –shelterbelt” it decreases. Fifteen years of fallowing is not enough to return the soil thermal diffusivity to virgin land values.

This study assessed the impact of soil surface contamination with used motor oil on the migration and accumulation properties of zinc and copper, as well as estimated the activities of soil urease and catalase, two of the most important parameters characterizing soil self-healing processes under oil contamination. X-ray fluorescence, titrimetric, infrared spectrometry, and other methods were used to determine soil parameters and analyze petroleum products. Six years of monitoring under field experimental conditions revealed a significant accumulation of zinc in the surface soil layer (0–10 cm)—up to three times that of the control. This accumulation was due to the increased influence of the natural geochemical barrier—the upper organogenic soil horizon—by the added petroleum products, as well as the increased activity of ureolytic bacteria capable of precipitating this metal as insoluble carbonate minerals. Copper exhibits significant mobility under contaminated conditions, characterized by migration from the 0–10 cm layer and accumulation at a depth of 10–30 cm, exceeding the control level by up to 2.6 times, due to the high affinity of this metal for water-soluble fractions of petroleum hydrocarbons, heavy precipitation that fell during the monitoring period, and the presence of a thick clay layer at a depth of 60 cm and below, which served as a geochemical barrier preventing its further downward migration. Urease activity in the soil increased significantly, which was observed throughout the experiment. Soil catalase activity was inhibited immediately after the application of the petroleum product to the soil, and by the end of the study period, it increased to values 47,6% higher than the control level, indicating a gradual restoration of the microbiota and stimulation of soil self-purification processes.

This work aimed to study the effect of sorbents on the phytotoxicity of soils of heaps by changing the values of germination energy and seed viability, as well as morphometric indicators of model plants.Three dumps were selected as the objects of research – two rock dumps (Kalinin mine, Zaperevalnaya mine and one dump of a central processing plant (Chumakovskaya CPP), located on the territory of the Donetsk coal basin within the city of Donetsk, Donetsk People's Republic. Soil of heaps was used for laboratory modeling, as well as soil with the addition of biochar (1%) and layered MgFe-LDH double hydroxide (0.5%). Festuca rubra L. and Trifolium rubens L. were used as test cultures. It was found that the phytotoxicity of technogenic ecotopes had an inhibitory effect on the seed viability and germination energy of the seeds of both test crops. The greatest phytotoxic effect was found for embryozems of the Chumakovskaya CPP, where the decrease in seed viability and germination energy was 83–92% relative to the control. The most sensitive indicators were the length and mass of the root. The submission of sorbents, especially MgFe-LDH, contributed to a decrease in phytotoxicity, most pronounced on the embryozemsof the Chumakovskaya CPP, which was confirmed by the positive dynamics of morphometric parameters. According to the integral toxicity index, the rock of the dump of the Chumakovskaya CPP is assigned to hazard class I (extremely high toxicity), while the dumps of coal mines are classified as low toxicity or normal. The greatest positive effect was fixed with the use of MgFe-LDH, which not only stimulated growth processes, but also contributed to the transition of the substrate to the category of a lower hazard class.

Analysis of tilosin migration in sand and sod-podzolic soil: a laboratory filtration experiment A. K. Toskhoporan, A. P. Kiryushina, S. V. Patsaeva, A. Yu. Shulakov, A. D. Batakov, V. A. Terekhova, A. B. Umarova The migration of the antibiotic tylosin in fine-grained quartz sand and the upper layer of sodpodzolic soil was studied in laboratory filtration experiments to obtain output curves and calculate the parameters of antibiotic migration in variants with different pore structure. It was found that the transfer of tylosin can be tracked by analyzing its concentration in filtrate portions, measured by the absorption spectra of the antibiotic. It has been experimentally shown that the appearance of an antibiotic occurs in the first shift of the entire pore space of the column. Tylosin actively migrates in all variants of sod-podzolic soil, and its erosion front reaches 40 cm. Similar behavior of antibiotics and potassium cations in soil was revealed. A high negative correlation (k = 79% according to Pearson) was found between the direct method of determining the tylosin content in filtrates by spectrophotometry and its algotoxicity in migration experiments. Keywords:soil, porosity, granulometric composition, output curves, macrolide antibiotic, mixing step, migration, spectrophotometry, ecotoxicity.