Southern Chernozem Research Articles

Палеоэкологические условия в степной зоне Восточно-Европейской равнины в посткатакомбное время

The article is devoted to reconstruction of paleoecological conditions of the steppe zone of the Eastern European Plain in the late Middle Bronze Age. The buried soils of the Kurgan of the Babinskaya culture in the Bogucharsky district of the Voronezh region were studied. It is shown that chemical properties of soil are determined by winter precipitation, while the state of its microbial community reflects the moisture content in the warm season. Annual precipitation trend in the steppe zone in the post-Catacomb period was reconstructed on the basis of findings of a comparative analysis of the chemical and biological properties of soils. It has been established that soils at the end of the 3rd millennium BC showed obvious signs of aridization, which led to a change in soils properties and types causing Southern Chernozems (rich black soils) formation in areas where Ordinary Chernozems is currently located. At the same time, microbial biomass in the buried soils significantly exceeded the current values, and the structure of soil microbial community was dominated by microorganisms involved in plant litter decomposition, which indicates favorable summer conditions and intense summertime precipitation. The research data do not relate to the crisis narrative regarding the paleoecological conditions of the late Middle Bronze Age in the steppe zone of the Eastern European Plain. Furthermore, results obtained do not support the idea of crisis as some kind of comprehensive complex of negative natural and social phenomena. It is more correct to speak of an asynchronous change in the annual course of moisture supply with a decrease in winter and an increase in summer precipitation against the background of general climatic cooling. The article raises the question of the specifics of global climate change manifestation and consequences in the steppe zone generally referred to the “4.2-ka BP aridification event”, which caused drought in the lower latitudes and an increase in precipitation in high latitudes while undergoning a general cooling trend. It is suggested that, under those conditions, climatic fluctuation scale in the steppe zone, located intermediately between the boreal and tropical belts, was not so high. Thus, the steppe remained attractive for communities which managed to adjust their economic model to new conditions.

The Bioremediation Potential of Native Microorganisms of the Southern Chernozem

The Bioremediation Potential of Native Microorganisms of the Southern Chernozem

Ecological problems of irrigated soils in the south of Ukraine

Problem formulation. Ecological quality of soils and agricultural products depends on the level of irrigation water mineralization. The quality of mineralized irrigation water has a negative impact on soils, agricultural products and ecosystems. This is especially negative in the conditions of Southern Ukraine within the Black Sea territories where the formation of irrigation waters in the Ingulets river basin depends on the influence of the Kryvyi Rih iron ore basin located in the river basin. The aim of the article is to assess the impact of mineralized irrigation waters on soils and natural ecosystems. Materials and methods. Field sampling of water and dark chestnut saline soils and southern chernozem soils to determine the impact of mineralized water quality on soils and ecosystems, statistical analysis of the obtained data. Results. Discharges of highly mineralized mine waters into the river basin lead to a change in the flow velocity in the river from 4 m³/s to 20 m³/s, which negatively affects the flora and fauna living conditions. Depending on the chemical composition of the discharges, the mineralization of irrigation water varies from 1.393 g/dm³ to 1.7608 g/dm³, and sometimes reaches 4.349 g/dm³. In terms of chemical composition, irrigation water is formed as a hydrocarbonate-sulfate-chloride with almost the same content of sulfates and chlorides, calcium-magnesium-sodium with a significant advantage of sodium. The dynamics of irrigation water quality indicators during 2013-2021 testifies to an increase of the most dangerous indicators for soils: hydrogen index of soil solution (pH) from 7.7 to 8.4, chlorine ion content (Cl–) – from 9.52 to 10.77 meq/dm³ and sodium (Na+) from 9.52 to 13.33 meq/dm³. By means of correlation and regression analyzes, the regularities of water hydrochemical composition formation were revealed and a strong functional connection between mineralization and chlorine ions (r = 0.99) and sulfate ions (r = 0.99), between mineralization and hydrocarbonate ions was established (r = 0.47). As the mineralization of water increases, the content of chlorine ions and sulfate ions increases proportionally, and hydrocarbonate ions play a secondary role in the formation of the hydrochemical composition. To prevent the chlorine ions excess of more than 350 meq/dm³ and sulfate ions excess – 500 meq/dm³, irrigation water mineralization should not exceed 1500 mg/dm³, and to prevent the chlorine ions excess of more than 350 meq/dm³, water flow from the canal should be at least 9.0 m³/s. Scientific novelty. New mathematical models of the irrigation water mineralization, its anionic composition, its chloride content dependence on water consumption from the Ingulets river and the interdependence between mineralization and cationic composition of water are offered. Practical significance. The obtained results are of practical importance for the implementation of agro-ameliorative measures for soil and ecosystem conservation.

Paleogeographic and historical aspects of the ancient polis functioning on the example of the study of the «Orient» section of the Olbian necropolis

Paleogeographic and historical aspects of the ancient polis functioning on the example of the study of the «Orient» section of the Olbian necropolis

Bioremediation potential of native microorganisms of the southern chernozem

In the course of the conducted studies, main groups of soil microorganisms in the southern chernozem were identified. The resistance of isolates to the action of oil in the concentration range of 15–25%, the possibility of using it as a carbon source, the ability of soil microbiota to biodegradate oil in contaminated soil and the resistance of bacteria to low temperatures, high NaCl concentrations, acid and alkali resistance were established. 15 genera (31 species) of heterotrophic bacteria were isolated from uncontaminated soil samples of the southern chernozem subtype. Our assessment of the abundance dynamics of microorganisms isolated from laboratory contaminated soils showed that as a result of oil exposure, there was a significant decrease in the numbers of microorganisms: by the 180th day of our experiment, 10 bacteria species belonging to 3 genera were isolated, namely: Bacillus, Micrococcus and Serratia. Among the isolated bacteria, resistance to the action of the pollutant at a concentration of 25% was established for B. coagulans, B. mojavensis, B. megaterium, M. luteus, as well as for the museum strain of B. pumilus CM. By cultivating the studied bacterial strains on a carbon-free medium M9 with 15 and 20% oil added, their ability to use petroleum hydrocarbons as the only carbon source was established; however, when the concentration increased to 25%, only M. luteus, B. mojavensis and B. pumilus KM retained this ability. The presence of hydrocarbon-oxidizing bacteria in soil samples contributed to the 42% decrease in the oil mass concentration in 180 days. The most significant decrease in the concentration of petroleum products occurred in the period from the 10th to the 30th day and amounted to 25%, which is probably due to the increase in the numbers of heterotrophic bacteria. The ability to grow at a temperature of +4°C was established for representatives of the genus Bacillus, including the museum strain of B. pumillus CM, 4 strains of bacilli remained viable in an acidic environment (pH 5), 7 strains of bacilli and M. luteus and S. plymuthica remained viable in an alkaline environment (pH 9). The studied bacterial strains were growing on a GRM-agar with a NaCl concentration of 7%, the ability to grow at a NaCl concentration of 15% was preserved only by the museum strain of B. pumillus KM. The obtained results open the prospects for the use of hydrocarbon-oxidizing bacteria with a high adaptive potential as potential oil destructors capable of biodegradation at low temperatures, in conditions of high salinity and in a wide range of pH of the medium.

Biophysicochemical properties of the eroded southern chernozem (Trans-Ural Steppe, Russia) with emphasis on the <sup>13</sup>C NMR spectroscopy of humic acids

The morphological, water-physical and chemical properties, basal respiration of the southern chernozem (Chernozem Haplic Endosalic) and erosional sediment in the Trans-Ural steppe zone (Republic of Bashkortostan, Russia) were studied. The surface soil horizon significantly differs from the sediment by the better structure and water aggregate stability. The particle size distribution of the sediments, due to erosion, contains more silt and clay fractions compared to the slope soil. It indicates a great potential for the carbon saturation of the soil which is limited by degradation. The slope soil is slightly saline, the type of the salinisation is sulfate with the participation of hydrocarbonates. The СО2 emissions, the organic carbon and alkaline-hydrolysable nitrogen content is low; and significantly lower than in the erosional sediment, but the content of exchangeable cations and water-soluble salts is higher. The structural composition of the humic acid (HA) extracted from the soil and erosional sediments was determined by 13C NMR spectroscopy. Aliphatic structural fragments predominate (65%) with a maximum signal level in the area of C, H-alkyls in the HA of the surface horizon. In the HA of the erosional sediment, the proportion of aromatic structural fragments is higher (up to 59%), which is associated with the processes of hydrolysis and condensation. In the HA of the slope soil, the formation of predominantly C, H-alkyls, oxygen-containing groups, including carboxyl ones, takes place. Differences in the composition of the structural fragments and functional groups of the soil and sediment HA are due to the different stability of the organic matter under conditions of the development of the soil erosion processes.

APPLICATION OF EXTRASOL ON SOFT WHEAT IN THE CONDITIONS OF KOSTANAI REGION

Studies have been carried out to determine the increase in the resistance of soft wheat variety Omskaya-36 to diseases from the use of the microbiological preparation Extrasol: 2020 - Kostanay district, I-II natural-climatic zone; southern chernozem, heavy loamy, soil solution reaction pH - 8.3, humus content 3.3%; 2022 - Karabalyk district, I-II natural and climatic zone; ordinary chernozem soil solution pH - 7.2, humus content 3.5%. To determine the effectiveness of the microbiological preparation Extrasol on the restraint of the spread and development of diseases, field plots were selected with annual sowing of spring wheat (monoculture).It was determined that the use of the microbiological preparation Extrasol reduced the suppression of the most common diseases in the conditions of the Kostanay region on spring wheat, and timely treatment made it possible to block the development of pathogenic diseases, which ensured the further development of plants.

The influence of the microbial preparation BakSib on winter barley and the state of southern chernozem

In the article, the authors showed the effectiveness of bacterization of winter barley variety Basalt with a complex microbial preparation BakSib. The authors used a semi-dry method of seed treatment (10 l/t of working solution) and a single treatment of vegetative plants on the southern chernozem together with chemical pesticides and without them. After treatment with the drug was observed: 1) a decrease in the number of microscopic fungi in the soil up to 3 times in the tillering phase and by 21% in the full ripeness phase in comparison with the control; 2) an increase in the number of ammonifiers from 44 to 81.4%; 3) an increase in the number of bacteria that assimilate mineral nitrogen from 79 to 116%. The authors revealed the stimulating effect of BakSib on the height of barley plants in all growth phases by 7.9–13.3% compared to the control. The yield of barley increased to 9%, and the number of grains per ear increased by 9.6% compared to the control and by 6.4% when comparing the full technology of plant protection of the farm and additional bacterization with BakSib. The authors also determined the compatibility of BakSib with the insecticide Clothianidin Pro (clothianidin 350 g/l) and the fungicide Sphinx (tebuconazole 60 g/l) for seed dressing. During the study, the authors found that under the action of chemical protectants, the initial titer of the biological product (1010–1012 cells) is reduced by 3-4 times. The maximum decrease noted for individual groups of Baksiba microorganisms is two orders of magnitude. The drug contributed to a prolonged increase in copiotrophic bacteria in the southern chernozem and replenishment of its nitrogen fund during the heading period, which is important for grain productivity due to increased mineralization of organic residues in the soil.

Agronomic evaluation of irrigation water on the Southern Buh and Kamianska irrigation systems

The aim of the research was to study the temporal and spatial dynamics of a set of agronomic criteria for irrigation water in the process of transporting it from the Southern Buh River intake site to the lands of the Southern Buh and Kamianska irrigation systems situated in southern Ukraine. Six stationary research sites for monitoring the quality of irrigation water were established along the route of irrigation water transportation. Determination of agronomic criteria for irrigation water quality was carried out in two terms: at the beginning of the irrigation season, in May, and at the end, in September. The content of cations of sodium, magnesium, calcium, and anions of chlorine, sulphates, carbonates, and bicarbonates was determined. In the field, the pH and electrical conductivity of water, the total salt content, and the total amount of dissolved solids were determined. It is determined that waters have an average level of danger from the point of view of salinisation of soils. This fact leads to a decrease in yield of sensitive to salinity crops (corn, alfalfa and most vegetables). The high content of sodium cations along with the low content of calcium and magnesium cations indicates the danger of degradation of the physical properties of the southern chernozems and the need to use the meliorants containing calcium. There is a high probability of toxic effects on crops caused by sodium cations. At the same time, it is stated that there is no negative effect of chlorine anions on plants.

Agroforestry-Enhancing Typification of Agricultural Territories as a Basic Condition for Increasing the Efficiency of Protective Afforestation

Upgrading the scale of agricultural production and the effectiveness of protective afforestation is based on the strategy of identifying similar crop production conditions. The given research identifies the territories that require different approaches to forest reclamation. The research is based on the use of remote data as well as geoinformation research methods. The area for investigation is the territory of the right bank of the Khoper River in the Volgograd region. This territory is characterized by the distribution of the most fertile soils in the world, southern chernozems and typical chernozems. The study area is a long-standing historical center of agricultural production, and the task of protecting and increasing the fertility of cultivated soils is very urgent for this territory. The investigation of the catchment areas for identifying spatial patterns is an important methodological aspect of the present research. The studies were carried out within the network of catchments in ravines and gullies. The parameters of the areas of each catchment were used to calculate the specific indicators characterizing the territory. Mapping the territory of the research area made it possible to identify the range of parameters which characterize the erosion process as well as the parameters that cause its development. The studies of the interdependence of land structure and relief parameters made it possible to identify the processes for evaluating the agroecological state of the territories and their typification. These parameters include: erosive dissection, km/km2; the density of ravine tops, units/km2; the area of arable land in the catchment located on slopes with a steepness of more than 3°, %; and the nonforested area of slopes with a steepness of more than 8°. The values of indicators estimated on the basis of statistical scoring procedures became the basis for the allocation of four groups of conditional agroecological states of territories: normal, risk, crisis, and disaster. These groups differ in the set of reclamation measures used and their focus and scope.

Modernization of strip-till technology in the cultivation of corn for grains in Ciscaucasia

Relevance. The cultivation of tilled crops with the introduction of new technologies requires a scientific justification of their effectiveness, taking into account the emerging soil and climatic factors. The use of the modernized Strip-till technology is based on the surface treatment of stubble with disc tools, against the background of stubble treatment with glyphosate, which preserves productive moisture.Methods. Research in scientific and production experiment was carried out in the zone of unstable moisture in the southeastern part of the Stavropol Territory on the southern chernozem (humus — 3.0%; PO5 — 11.3 mg/kg; K2O — 276 mg/kg; pH — 7.48). The main moldboard cultivation according to the traditional technology was carried out with a plow PN-82-35, according to the Strip-till technology — deep non-moldboard cultivation with a cultivator — a Blu-Jet slot cutter.Results. Unfavorable climatic conditions of the summer-autumn period of 2018, 2019 and 2020, with a shortage of precipitation in July 2018 by 20.2 mm, in August 2019 by 33.6 mm and in July 2020 by 51.4 mm from the norm, caused reduction in the yield of corn for grain.W ith a higher density of the soil for non-moldboard cultivation in comparison with the moldboard one for the periods of observation, which is 0.02, 0.04 and 0.02 g/cm3 respectively, an increase in capillary porosity by 7, 5 and 3% is noted. Accordingly, a larger supply of productive moisture in terms of sampling at Strip-till is associated with a large volume of capillary pores, with a direct correlation (r = 0.86). The increase in the reserves of productive moisture by Strip-till in the periods of observation, in comparison with dump processing, was 9, 10 and 7 mm, which led to an increase in the yield of corn for grain by 0.24 t/ha and profitability —by 33%.

Influence of irrigation and weather conditions on the duration of interphase periods of winter wheat varieties

The autumn growth and development of plants depend on a complex of external factors: the average daily air temperature, the amount of precipitation, the humidity of the seed layer of the soil, nutrients, light, etc. If winter wheat is sown at a later date, there are risks that the plants will enter the winter not well developed. It is possible to accelerate the passage of interphase periods with the help of irrigation, which is a necessary agrotechnical measure in the Southern Steppe of Ukraine. The purpose of the research is to establish the influence of varietal characteristics, irrigation and weather conditions on the duration of interphase periods of winter wheat in the autumn period on an international scale. Experimental research was carried out during 2020-2021 on southern chernozem, on the basis of the Educational Scientific and Practical Center of the Mykolaiv NAU with two varieties of winter wheat. Field, laboratory and comparative calculation methods were used during the research. The establishment and conduct of experiments were carried out according to the methodology of the research case. Soil moisture was determined by the thermogravimetric method, and phenophases were determined simultaneously throughout the experiment. It was determined that irrigation for 1-2 days reduces the duration of the interphase period of BBCH 00-09; for 3 days – BBCH 10-12; for 11 days – BBCH 13-19; for 5-7 days – BBCH 20-22. In natural conditions (without irrigation), the duration of the interphase periods (from BBCH 00-09 to 20-22) of the growth and development of plants of the studied varieties of winter wheat in 2020 was 93-96 days, which is 23-25 days more than in 2021. In plants of the Ovid variety under conditions of natural moisture (without irrigation), the interphase periods came 1-3 days later than in the Duma Odeska variety, while under irrigation conditions there was no significant difference. The obtained scientific results of the research will contribute to the wider implementation of irrigation, which will ensure the rapid and full growth and development of winter wheat plants in the autumn period, which will further contribute to increasing the yield and gross harvest of grain

Efficiency of application of compost of liquid poultry manure under sunflower in southern chernozem

The article presents the results of three-year field experiments on the application of compost of liquid poultry manure on sunflower crops in the conditions of southern chernozems of the Rostov region. The application of compost increased the yield of sunflower seeds by 0.21-0.67 t/ha, the oil content of seeds - by 2.3-3.5%. It has been established that the maximum yield of sunflower seeds was in the variant with the introduction of 20 t/ha of chicken compost in autumn during plowing, which significantly exceeds the maximum dose of N75P75K75 mineral fertilizers in terms of efficiency. A positive economic effect was after application of compost of liquid chicken manure. An increase in the level of profitability in the experiment compared to the control variant (fertilization) was with an increase in the dose of chicken compost to 10 t/ha, a further increase in the dose led to a decrease in economic efficiency.

Дистанционный мониторинг государственных защитных лесных полос степной зоны европейской части России

State forest shelterbelts are not only one of the components of the ecological framework of sparsely forested steppe territories, but also represent a unique object of steppe afforestation. Age-related changes and a long-term absence of forestry impact negatively affected the sanitary condition of plantations of the state forest shelterbelts. The research is aimed at assessing the current state of the plantations that form the shelterbelts in different soil and climatic conditions in the steppe zone of the European part of Russia. The plantations of the coastal state forest shelterbelts “Voronezh – Rostov-on-Don”, “Belgorod – Don River” and watershed “Volgograd – Elista – Cherkessk” were the research object. The expediency of using the method of remote sensing of the Earth is due to the significant extent and differences in the state of the research object in different soil and climatic conditions. An analysis of the natural conditions of the research region made it possible to determine the boundaries of 5 forestry regions on the main subtypes of zonal soils: ordinary chernozems, southern chernozems and dark chestnut soils; chestnut soils; light chestnut soils with the presence of solonetz and sometimes solonchak soils; and also on azonal sandy soils. Based on the data of our own field surveys of artificial plantations, the interpretation of space images of state forest shelterbelts was carried out using the learning algorithm and spectral indices in the ENVI 5.2 software package. As a result of interpretation, it was found that the safety of state forest shelterbelts decreases as forest conditions become more severe from ordinary chernozems to light chestnut soils from 92.3 to 36.5 %. Oak forests, ash forests, and elm forests predominate in the species composition on zonal soils, and pine forests predominate on azonal soils. With the deterioration of forest site conditions, the share of oak in plantations decreases, it is replaced by elm, the density of plantations decreases. Forest strips on chernozems, dark chestnut and sandy soils are also the most prosperous in sanitary terms. Plantations growing on chestnut and light chestnut soils are characterized by digression increasing with age or complete decay of the forest environment. The conducted research allows to identify the location of plantations in the stage of degression or decay within the state forest shelterbelts, and to recommend for them the nature and volume of forestry impact for the conservation and restoration of the forest.

Adaptability of the Sorghum Bicolor Rhizosphere Microbiocoenosis Inoculated by Microbial Agents in Southern Chernozem Soils

Adaptability of the Sorghum Bicolor Rhizosphere Microbiocoenosis Inoculated by Microbial Agents in Southern Chernozem Soils

Impact of the No-Till technology on erosive degradation of soils in hollows

The present research is aimed at studying the impact of the modern no-till agricultural technology on the development of erosion processes on cultivated arable land in the subzone of the southern chernozems of the Volgograd region. Evaluation of the impact of this agricultural technology was based on the analysis and comparison of soil cover in hollows located in the fields cultivated using either the classic technology or the no-till technology. The research methodology is based on combination of remote, field and laboratory methods for studying the soil cover. Analysis and generalization of data obtained in the course of laboratory studies of selected soil samples made it possible to identify a high degree of erosion processes in the hollows located in the fields, which had been cultivated using the no-till technology for three years. Comparison of the values of the content of organic carbon in the zones of removal, transit and accumulation of fine earth indicates the development of water degradation processes in the middle part of the hollows. Thus, for soil samples taken from a depth of 0-10 cm, the value of organic carbon content in the variant of soil tilled using the new technology is 2.6%, while in the variant tilled using the classic technology, this value is equal to 3.1%. The revealed differences in the soil cover of the hollows can be explained by interaction of the patterns of development of erosion-accumulation processes and the features of the no-till technology in specific natural and climatic conditions.

Use of digital characteristics of soil color for assessing the degree of soil erosion

The present study is aimed at developing and improving approaches to assessment of the degree of soil erosion. The transition from verbal to digital form of determining the color of soils expands the possibilities of using this morphological feature. It allows determining the thickness of soil horizons based on the data of laboratory analysis of the color of soil samples. The methodological basis of the study is represented with the index method or the method of field standardization of territories. According to this method, the main contour of the soil is characterized by a full-profile soil pit, and soil changes caused by the relief near the main pit are estimated by changes in the characteristics of soil layers. Measurement of the latter was carried out in the course of the laboratory analysis of soil samples selected by soil drilling. As a result of the study, the soil color coordinates were determined in the CAI Lab system. Their values correspond to the soil samples of the southern chernozem taken at a depth of 1 meter every 10 centimeters. The linear nature of interconnection between the index of organic carbon content in the soil samples and the corresponding values of the lightness index in the CAI Lab color model was confirmed. The soil samples with varying degrees of erosion were identified in a research object: soils of watersheds unaffected by erosion processes; moderately eroded soils of hollows exposed to water erosion; drift soils of the mouth of hollows.

Soil-biological methods in monitoring the processes of turning the steppe into a meadow near lake ecosystems of Khakassia

The article analyzes the results of the study of microbiological and zoological components in the soils of lake territories in the steppe zone of the Khakassia Republic. It is shown that the transformation of the zoo-microbial complex of the southern chernozem in the process of turning the steppe into a meadow occurs along the way of reducing the biomass of soil microorganisms and a sharp increase in the total and specific metabolic activity of this biomass. At the same time, a sharp decrease in the number of oribatids occurs in the process of turning the steppe into a meadow, with the practical immutability of species richness. At the same time, the composition of the oribatid community is undergoing a radical transformation. These changes in the zoo-microbial complex are associated with changes in the level of soil moisture. The conducted research demonstrated that the identified features of the studied biological and soil indicators (microbiomass, respiration of biomass and metabolic coefficient, the number and species richness of oribatid mites) can be successfully used in the practice of monitoring the process of turning the steppe into a meadow on lake territories in the steppe zone of the Khakassia Republic.

Evaluation of soils of the roadside territory area of the federal highway on the maintenance of heavy metals, arsenic and fluoride ions

Introduction. A hygienic assessment of the fluoride ions, heavy metals (HM) and arsenic content in the soils of the roadside area of the Ryazan-Volgograd highway was carried out. Materials and methods. The assessment was obased on the results of soil sampling from 11 sites over the Ryazan-Volgograd highway along its entire length at distances of 20 and 50 m from the roadbed. To assess the impact of vehicles on roadside soil pollution and exclude industrial sources of pollution, soil samples were taken outside settlements and industrial zones of cities. Results. The content of water-soluble fluorine in the studied soils was found to vary in the range significantly lower than the values of the maximum permissible concentration. With distance from the highway, the concentration of fluorine in the soil decreases, indicates its aerogenic origin. According to sanitary standards, its content corresponds to the permissible level. The accumulation index of HM and arsenic in the soil of the roadside area increases in the order: As → Ni → Zn →Pb → Cu. Cu has the maximum accumulation index, which varies from 1.24 to 4.34, depending on the soil types of the roadside territory. The accumulation of such pollutants as Pb, Zn was noted in the roadside areas represented by southern chernozems and dark chestnut residual calcareous soil types. The highest hazard coefficients are related to As on southern chernozems; Cu and Ni - on gray forest soils of the roadside territory of the federal highway. Limitations. The limitations of the study are associated with one-time sampling and a small number of reference sites, which limits the possibilities of a broader interpretation of the data obtained to determine trends in soil pollution of roadside areas. Conclusion. With the same technogenic load on the roadside area caused by the movement of passing motor vehicles, the self-cleaning ability of different soil types can differ significantly. On those parts of the roadside area where heavy metals are accumulating, it is necessary to organize constant environmental and hygienic monitoring and carry out measures for soil remediation.

Approaches to the development of environmental regional standards for the content of lead in the soils of the Black Sea coast of the Caucasus on the basis of an integral indicator of the biological state of the soil

Introduction. The Black Sea coast of the Caucasus is an actively developing region with a progressively growing tourism and recreation infrastructure. However, there are rare and unique soils, such as southern chernozems (chestnut), brown soils of dry subtropics, yellow soils. Lead (Pb) is a priority group of toxicant metals. However, the use of uniform, common standards of Pb content in all types of soils is impractical, since local regional ecological and geochemical features of soils are not taken into account when calculating them. Materials and methods. Soil contamination of 100, 1000, 10,000 mg Pb per 1 kg of soil was modelling, corresponding to 1, 10 and 100 MPC of this element in Germany and several other countries. After 30 days, changes in biological parameters (the number of bacteria, the activity of soil enzymes and length of roots of radish) were evaluated. To combine the values of the studied biological indicators with different units of measurement into one common indicator, an integral indicator of the biological state (IIBS) of the soil was used. Results. In most cases, there was an inhibition of the biological properties of the studied soils. According to the resistance to Pb pollution, the soils of the Black Sea coast of the Caucasus form the series including southern chernozems (Haplic Chernozems Pachic) (85) > cinnamonics typical (Haplicisols Eutric) (79) ≥ soddy-carbonate typical (Rendzic Leptosols Eutric) (77) ≥ cinnamonics leached (Haplic Cambisols Eutric) (76) ≥ cinnamonics carbonate (Haplic Cambisols Eutric) (74) = sod-calcareouses leached (Rendzic Leptosols Eutric) (74) = yellow soils (Albic Luvisols Abruptic ) (74) > brown forest weakly-unsaturated (Haplic Cambisols Eutric) (67) ≥ brown forest acid (Haplic Cambisols Eutric) (65) > brown forest acid podzolized (Haplic Cambisols Dystric) (59). On the base of the analysis of the degree of failure of environmental functions of soils, regional values of maximum permissible concentrations (rMPC) of Pb in soils of the Black Sea coast of the Caucasus are established. Regional values of maximum permissible concentrations of Pb for southern chernozem is 120 mg/kg, for cinnamonics typical, cinnamonics leached, cinnamonics carbonate, sod-calcareouses leached, sod-calcareouses typical soils and yellow soil - 100 mg/kg, for brown forest acid, brown forest weakly-unsaturated - 70 mg/kg, 65 mg/kg for brown forest acid podzolized. Limitations. The proposed maximum permissible concentrations of Pb in soils are applicable primarily to the territory of the Black Sea coast of the Caucasus. Conclusion. The proposed maximum permissible concentrations of Pb in the soils of the Black Sea coast of the Caucasus can be used by environmental, agricultural and scientific institutions.