Enzymatic activity of soils is the most important diagnostic indicator of the ecological state of soils affected by various types of anthropogenic impact. The aim of the study was to evaluate the enzymatic activity of ordinary chernozem (Haplic Chernozem) contaminated with Ag, Bi, Te, and Tl. Ten enzymes (catalase, dehydrogenase, peroxidase, polyphenol oxidase, ascorbate oxidase, ferrireductase, protease, phosphatase, invertase, and urease) were analyzed. According to the degree of inhibition of enzymes, heavy metals formed the following sequence: Tl > Ag > Bi > Te. With an increase in the concentration of heavy metals, the toxic effect on the activity of enzymes increased. The oxidoreductases showed greater sensitivity to Ag, Bi, Te, and Tl contamination than hydrolases. Among oxidoreductases, the highest sensitivity was found for ferrireductase, and the lowest one for ascorbate oxidase. According to the activity of enzymes of the hydrolase class, invertase was the most sensitive, and urease was the least sensitive. When contaminated with Ag, Bi, and Te, invertase had the highest informative value, and when contaminated with Tl, urease and polyphenol oxidase were the most informative. Among the enzymes of the oxidoreductase class, the highest information value was found for peroxidase, and the lowest one for ascorbate oxidase. Among the enzymes of the hydrolase class, invertase was the most sensitive, and phosphatase was the least sensitive. The results of the study can be used to assess the ecological state of soils contaminated with Ag, Bi, Te and Tl.

Wildfires result in the emission of large volumes of toxic smoke, which is transported hundreds of kilometers away from the fires and can have an adverse impact on soil, biota, and humans. A series of modelling experiments on pyrogenic fumigation of soil has been carried out to assess the effects of gaseous products of wildfires on soil biochemical parameters. The effects of continuous exposure to gaseous substances and periodical, repetitive effects of smoke exposure on soil have been determined. The results have been compared with a single intense smoke exposure. It was found that pyrogenic impact significantly affected the enzymatic activity of ordinary chernozem. The degree of influence depended on the duration and periodicity of smoke exposure. In all experiments, enzymes of oxidoreductase class (catalase, peroxidase, polyphenol oxidase) were more sensitive to fumigation than invertase from hydrolase class. High concentrations of toxic gases were the cause of suppressed enzymatic activity of soils. The following concentrations exceeded the maximum permissible concentrations for atmospheric air: CO 714 times, phenol (hydroxybenzene) 441 times, acetaldehyde 24100 times, formaldehyde 190 times. Accumulation of polycyclic aromatic hydrocarbons (PAHs) in soil after fumigation was revealed, the total content of PAHs was 377 ng/g. The highest values were recorded for naphthalene, where the concentration was 4.4 times higher than the maximum permissible concentration and phenanthrene, 2.8 times higher than the maximum permissible concentration. It has been found that 60-min intensive smoke affects the soil to a lesser extent than continuous and periodical ones. Indices of enzymatic activity of chernozem after such fumigation decreased by 15–33

The effect of contamination of ordinary black earth with platinum oxide (PtO2) on biological properties: root length and germination of radish, total number of bacteria, abundance of bacteria of the genus Azotobacter, activity of catalase and dehydrogenases have been studied. The concentrations studied were 0.01, 0.1, 1, 10 and 100 mg/kg in 10, 30 and 90 days after contamination. A stimulating effect (hormesis) of platinum oxide at a concentration of 0.01 mg/kg on the biological properties of ordinary black earth was recorded. It was found that in other cases, platinum oxide has a negative effect on the studied parameters, and exhibits the greatest toxicity after 30 days after contamination, followed by restoration of soil properties after 90 days. It was concluded that the most sensitive (highest degree of reduction) indicators to platinum oxide contamination were the total number of bacteria, germination and length of radish roots. Early diagnosis of the degree of soil contamination with platinum compounds is recommended in order to obtain a prompt assessment of the impact and prevent possible negative consequences.

Thallium ecotoxicity was assessed in laboratory model experiments by changing in microbiological, biochemical, and phytotoxic properties of soils in the South of Russia: ordinary chernozem (Haplic Chernozem (Loamic)), seropesok (Eutric Arenosol), and slightly unsaturated brown forest soil (Eutric Cambisol), differing in texture, pH, and organic matter content. There was usually a direct relationship between Tl concentration and the deterioration rate of the studied soil properties. The ecotoxicity of Tl nitrate was higher as compared to Tl oxide. The ecotoxic effect of Tl was the strongest for chernozem and seropesok within 10 days and for brown forest soil within 30 days after contamination. Restoration of biological soil properties was recorded on the 90th day. The resistance to Tl contamination was the greatest for ordinary chernozem and the smallest for seropesok. The results obtained indicate a high ecotoxicity of Tl.

The results of studying the effect of fires on the biological properties of brown soils of xerophytic forests (Skeletic Leptic Cambisol) of the Utrish State Nature Reserve, Krasnodar Territory (crown fire of 2020), and burozem of mesophytic forests (Haplic Cambisol (Loamic)) of the Khamyshinsky forestry, Republic of Adygea (ground fire of 2018) are presented. Changes in the reaction of the soil environment, the content of organic carbon, and the activity of such enzymes as catalase, urease, phosphatase, and invertase involved in the cycle of carbon, phosphorus, and nitrogen have been studied. The reaction of enzymes to pyrogenic effects depends on the type of enzyme and the type of soil. A factor analysis was also carried out. The activity of catalase and invertase for two types of soils in a layer of 0–3 cm decreased by an average of 47%, while the reaction of phosphatase and urease differed depending on the soil type. Two years after the fire, the phosphatase activity of the surface layer of post-pyrogenic brown soils approached the control values; urease activity recovered more slowly compared to other enzymes. Four years after the fire, in the 0–3 cm layer, for the post-pyrogenic acid burozem, on the contrary, the values of urease activity approached the control values. An increase in pH values by an average of 30% and a decrease in the content of Corg by an average of 12% were also established for two types of soils. In the 3–10 cm layer, for brown soils, an average increase in the activity of all the studied enzymes was noted, while for acid burozem, on the contrary, a decrease. Factor analysis showed the presence of a relationship between the reaction of the soil environment, the content of organic carbon and the activity of enzymes, while the tightness and nature of the relationship differed depending on the type of soil. The results obtained indicate the influence of the edaphic features of the studied soils on the response of enzymatic activity to pyrogenic exposure.

The results of studying the effect of fires on biological properties of cinnamonic soils of xerophytic forests (Skeletic Leptic Cambisol) of the Utrish State Nature Reserve, Krasnodar krai (crown fire of 2020), and burozem of mesophytic forests (Haplic Cambisol (Loamic)) of the Khamyshinsk forestry, Republic of Adygea (ground fire of 2018) are presented. Changes in the soil reaction, in the organic carbon content, and in the activity of enzymes: catalase, urease, phosphatase, and invertase involved in the cycle of carbon, phosphorus, and nitrogen have been studied. The reaction of enzymes to pyrogenic effects depends on the enzyme kind and the soil type. The factor analysis was also performed. The activity of catalase and invertase decreases by 47

The paper presents the results of our study on the effect of one type of pyrogenic factor (smoke) after burning coniferous wood chips on several bioindicators (soil enzymes, microorganisms, mesofauna, plants of agricultural crops). Exposition to smoke for 60 minutes was found to significantly affect the enzymatic activity of common chernozem. Fumigation caused a decrease in such enzymes as catalase, peroxidase, polyphenol oxidase and invertase. The enzymes of the oxidoreductase class were the most sensitive to smoke. High toxicity of gaseous combustion products to the soil flora and fauna was revealed. The acute toxicity of smoke to the bioindicators was determined as a result of fumigation. High mortality of test objects ( Eisenia fetida, Nauphoeta cinerea ) was recorded in our experiments. Soil microorganisms ( Azotobacter chroococcum and Penicillium chrysogenum ) proved to be informative after 30–120 minutes of fumigation. Resistance of plant sprouts ( Raphanus sativus, Triticum aestivum, and Pisum sativum ) to combustion gaseous products was revealed. An experiment to analyze the chemical composition of gases in smoke was performed. Such hazardous compounds as sulphur dioxide (SO 2 ), nitrogen oxide and dioxide (NO, NO 2 ), carbon monoxide (CO), acetaldehyde (C 2 H 4 O), formaldehyde (CH 2 O), phenol (C 6 H 6 O) hydroxybenzene and others were found to be contained therein. Our analysis revealed that the concentrations of carbon monoxide were 714 times higher than its maximum permissible concentration (MPC), which acetaldehyde was 24,100 times higher. The nitrogen oxide and nitrogen dioxide concentrations were 100 and 300 times higher, respectively.

An attempt has been made to assess the effectiveness of remediation of the tailing’s storage facility of a mining enterprise for the performance of ecosystem functions by a formed soil-like body in comparison with the background soil for this territory. To assess the biological properties of the soil-like body, the following were analyzed: the total number of bacteria, the abundance of bacteria of the genus Azotobacter, the activity of soil catalases and dehydrogenases, germination, and length of radish roots. An integral indicator of the state of the soil-like body was calculated for a comprehensive assessment of the effectiveness of tailings pond reclamation. It was found that the soil-like body of the reclaimed tailings dump performs its ecosystem functions as fully as the background mountain meadow chernozem soil for this territory. It is concluded that the reclamation works were carried out effectively with the restoration of the ecosystem.

The aim of the study Assessment of the floristic composition dynamics during four years after cessation of agrogenic influence on an long-term ploughed plot of ordinary chernozem at the Botanical Garden of the Southern Federal University. Location and time of the study. The research was conducted in the botanical garden of the Southern Federal University (Rostov-on-Don) in 2016-2019. Methods. Geobotanical descriptions were carried out according to conventional methods. Results. During the first four years of abandonement, the floral composition of the studied area increased from nine plant species in the first year to 48 species due to spontaneous revegetation. In the first year of the postagrogenic regime, Asteraceae were the dominant family (96% of the total number of species). Subsequently, the share of this family decreased by 45% after two years and by 40% after three years. Four years after the start of the experiment, in addition to the Asteraceae family (33.3%), Poaceae (17%), Brassicaceae (4.2%), Apiaceae (4.2%), Polygonaceae (4.2%), Fabaceae (4.2%), Rosaceae (4.2%) prevailed in the community, whereas the remaining families accounted for 29%. The productivity of the abandoned site depended on the season of the study. Compared with the first year of observations, the total phytomass stock decreased by 26% by the fourth year of the postagrogenic regime. The spontaneous revegetation of the abandoned plot led to an improvement in the ecological condition and an increase in the biological activity of the soil. Conclusions. Abandonement of the arable land resulted in a rapid increase in flora diversity, in the first years mainly due to the Asteraceae family. Phytomass at the abandoned land increased in the first year due to the cessation of ploughing and consequent spontaneous revegetation. Vegetation development led to an improvement of the ecological condition and increased biological activity of the soil.

The study assessed the ecotoxicity of four chemical compounds of silver (nitrate, oxide, sulfide, nanoparticles) by the enzymatic activity of ordinary carbonate chernozem. The effect of nitrate, oxide, sulfide and silver nanoparticles at concentrations of 0.5, 1, 5, 10, 50 and 100 mg/kg on catalase and dehydrogenase activity was evaluated 30 days after contamination. In most cases, the negative effect of nitrate, oxide, sulfide and silver nanoparticles on the enzymatic activity of ordinary carbonate chernozem was noted. The degree of ecotoxicity of silver is affected by its concentration in the soil. Silver nitrate, which is highly soluble in water and provides greater mobility of silver in the soil, has a somewhat greater ecotoxicity. Practically insoluble forms in water (oxide and sulfide) showed slightly less negative effects. As a result of the study, the ecotoxicity series of four chemical compounds of silver were obtained by enzymatic activity: in % of the control by catalase activity (% of the control): nitrate (90) = nanoparticles (90) > sulfide (91) > oxide (92); by dehydrogenases activity (% of control): nitrate (80) > nanoparticles (81) > sulfide (83) ≥ oxide (83).

Представлены результаты влияния микробиологического препарата с фунгицидным действием в отношении грибов рода Fusarium на основе консорциума штаммов аэробных спорообразующих бактерий рода Bacillus на продуктивность ярового ячменя и активность почвенных ферментов (каталаза, дегидрогеназы, фосфатаза, инвертаза). Объектом исследования был чернозём миграционно-сегрегационный (Haplic Chernozem Loamic). Исследование проведено путём посева ярового ячменя и его дальнейшей обработки биопрепаратом в различных дозах: рекомендуемая (РД – 0,00001 мл/л), десятикратная (РД·10 – 0,0001 мл/л) и стократная (РД·100 – 0,001 мл/л). В результате исследования было отмечено увеличение активности фосфатазы и дегидрогеназ, выявлены фунгицидное воздействие препарата для почвенных микромицетов, а также увеличение продуктивности ярового ячменя при внесении рекомендуемой дозы. The results of the influence of a microbiological preparation with a biofungicidal action against fungi of the genus Fusarium based on a consortium of strains of aerobic spore-forming bacteria of the genus Bacillus on the activity of soil enzymes (catalase, dehydrogenases, phosphatase, invertase) and the yield of spring barley are presented. The object of the study was Haplic Chernozem Loamic. The study was carried out by sowing spring barley and its further treatment with a biological product in various doses: recommended (RD – 0.00001 ml/l), tenfold (RD * 10 – 0.0001 ml/l) and hundredfold (RD * 100 – 0.001 ml/l). As a result of the study, an increase in the activity of phosphatase and dehydrogenases was noted, a fungicidal effect of the biological product on the studied soil was revealed, as well as an increase in fertility when the recommended dose was applied, as well as an increase in the productivity of spring barley when making the recommended dose.

A study was made of the resistance of the biological properties of the main mountain and plain soils of the Crimea to gasoline pollution. It has been established that the soils of the Crimea differ significantly in the resistance of biological properties to gasoline pollution: the most stable are residual-calcareous and southern chernozems, and the least stable are brown forest acidic soils. It was revealed that the resistance of soils to gasoline pollution is determined by the structure and biological activity of the soil. It was determined that the allowable residual content of gasoline (PDOSB) in the soils of the Crimea varies from 0.45% (brown leached red-colored and incompletely developed chernozem) to 0.25% (brown forest acidic soil). It is recommended to use the value of EAPs for Crimean soils to assess and predict possible negative consequences when they are polluted with gasoline.

Animals have a significant impact on the territory where they live by the process of their lives. The studied objects are located in the zone of dry steppes, where climatic conditions limit the development of vegetation and contribute to changes in soil characteristics, which, in combination with the impact of animals, enhances the effect. The purpose of the work was to assess the impacts of animals on the ecological state of the soils of the enclosures of the Wildlife of the Steppe Association. In the course of the study, the main indicators of the ecological state of soils in enclosures with animals on the territory of the enclosures of the Wildlife of the Steppe Association in the arid regions of the Rostov region were determined. We explored enclosures of different sizes, with African ostriches (Struthio camelus), emu (Dromaius novaehollandiae), goats (Capra sp.), Przewalski’s horses (Equus ferus przevwalskii) and saigas (Saiga tatarica), and on the territory with semi-free grazing of ungulates, that is, horses (Equus caballus), camels (camelus bactrianus), buffaloes (Bubalus arnee), yaks (Bos mutus), and lamas (Lama ganicoe). The studied areas differed in the intensity of soil degradation. To assess the physical condition the moisture, temperature, density, and structure of the soil were determined; pH, the gross chemical composition of soils, humus content, and biological activity were also assessed, and plots were ranked according to the degree of pasture digression. In the course of the study, the enclosure with African ostriches had the maximum degree of degradation of ten, which is characterized by severe inhibition of vegetation and soil degradation. As well, the soil density in the enclosure with African ostriches was the highest, 1.49 g/cm3, and the percentage of structure was the smallest, 37%. These parameters had a close negative correlation with the pressure of the animals' hooves and paws on the ground (–0.9). The humidity level in the studied areas did not rise above 11%; despite this, the enzymatic activity of the soils no longer depended on hydrothermal conditions, but on the influence of excretions of animal waste products. In enclosures with ungulates, in particular in the enclosure with goats, the activities of catalase and urease were always higher than in other areas. A high content of humus, 10.3%, was also noted there, which is uncharacteristic for chestnut soils and confirms the influence of animal life on them. According to the research results, the lowest quality of the structure, humus, and biological activity, as well as increased soil density, occurred in the enclosure with the African ostrich. The data we obtained explain the decrease in the growth and development of vegetation in the area where animals kept in crowded conditions live.

— Soil tolerance towards contamination with platinum nanoparticles (PtNP) was assessed using biological parameters for soils of southern Russia differing in particle-size composition, organic matter content, and soil reaction. Model laboratory experiments were performed with samples from the upper (0–10 cm) layer of soils with contrasting genetic characteristics, i.e., ordinary chernozem (Haplic Chernozem (Loamic)), brown forest soil (Eutric Cambisol), and gray sandy soil under pine stand (Eutric Arenosol). PtNP concentrations of 0.01, 0.1, 1, 10, and 100 mg/kg were studied. Soil tolerance was estimated using sensitive and informative biological indices: the total number of bacteria, the activity of catalase and dehydrogenases, and germination degree of radish seeds, and radish root length. In most cases, low PtNP concentrations (0.01, 0.1, and 1 mg/kg) did not affect reliably the biological state of soils, whereas higher doses (10 and 100 mg/kg) worsened biological characteristics. The enzymatic activity of PtNP-contaminated soils decreased to a lesser extent than the phytotoxic and microbiological indices. Ordinary chernozem showed a higher tolerance towards PtNP contamination than brown forest soil and gray sandy soil. The results of this study can be used for predicting ecological risks of soil contamination with PtNP and for assigning the maximum permissible concentration for platinum in different soils.

There are presented new materials on the distribution of the Cypress Jewel Beetle Lamprodila (Palmar) festiva, first discovered in natural stands оf relict juniper forests in the vicinity of the villages Sukko and Bolshoi Utrish in the Abrau Peninsula of the Black Sea coast of the Caucasus.

Data on changes in the enzymatic activity of soils under pyrogenic impact in model experiments simulating natural fires are given. A series of experiments performed under laboratory and natural conditions were aimed at studying pyrogenic inhibition of the activity and dynamics of recovery of enzymes in postpyrogenic soils. The objects of the study were represented by gray-humus sandy soil (Arenosol) and chernozem with migrational and segregational forms of secondary carbonates (Haplic Chernozem (Loamic, Pachic) of Rostov oblast. Model experiments included soil treatment with gas burner flame (heat amount 87–435 × 103 J) and wood fuel combustion (10–279 × 106 J). The exposure duration was from 1 to 5 min in the first case and from 1 to 120 min in the second case. The revealed response of enzymes (catalase, invertase, urease, peroxidase, and phosphatase) to low-temperature plasma impact (1–120 min) depended on the enzyme group and exposure rate. It was found that the penetration depth of thermal effect of simulated fires was limited by the top soil layer (0–10 cm), and the radius of spread from the combustion source did not exceed 20 cm. The temperature varied according to the exposure period, source of heat, and fuel amount (400–600°C). Sandy soils and chernozem got heated and cooled at different rates. The activities of catalase, invertase, and urease were inversely related to the intensity of pyrogenic impact. The dynamics of restoration of the enzyme activity in postpyrogenic soils was analyzed. The invertase activity recovered faster than the catalase and urease activity, but it the recovery was still in complete in a year after fire. The results obtained testify to a significantly prolonged inhibition of enzymatic activity as a result of simulated natural fires.

Soil contamination with platinum nanoparticles is reproduced at a rapid rate, primarily because of the operation of vehicles with platinum exhaust gas converters. Already present on the territory with a concentration of platinum in the soil of more than 2 mg/kg, which is the maximum background content of 750 times. At the same time, the environmental risks of the adverse impact of platinum nanoparticles on the soil are practically not studied. The purpose of this work is to assess the consequences of different buffering capacities of soils to contamination with platinum nanoparticles in terms of biological parameters. Laboratory studies of soil resistance to pollution with platinum nanoparticles (PtNP) in the South of Russia were carried out, and their genetic properties were compared: Ordinary Chernozem (Haplic Chernozem (Loamic)), Brown Forest Soil (Eutric Cambisol), and Gray Sands (Eutric Arenosol). PtНЧ concentration studies 0.01, 0.1, 1, 10 and 100 mg/kg. Soil stability is assessed by the most sensitive and informative biological indicators of the state. It was found that the low content of PtNP (0.01, 0.1 and 1 mg/kg) in most cases does not lead to following the analysis of the biological state of the soil, and higher concentrations (10 and 100 mg/kg) lead to biological indicators. Soil enzymatic activity under PtНЧ contamination was inhibited to a lesser extent than phytotoxic and microbiological indicators. Common chernozem caused greater penetration to PtNP contamination than brown forest soil and gray sands. The results obtained were used to predict environmental risks in case of pollution of paid soils and to develop maximum allowable concentrations of platinum in soils of different buffering capacity.

The complex effect of tylosin and copper on the ecological state of the typical chernozem was estimated depending on the degree of change in its biological parameters. Indicators of the general contamination, the abundance of bacteria p. Azotobacter, catalase activity, length of shoots and roots of radish (Raphanus sativus L.) were studied. It was found that the degree of decrease in biological parameters depends on the concentration of antibiotics, the higher the concentration, the more pronounced the interaction with heavy metals and, therefore, the more significant the inhibitory effect on biological parameters.

Regional maximum permissible concentrations of gross lead in soils were determined in the area of the non-ferrous metallurgy enterprise – the largest Electrozink plant in Russia, located in Vladikavkaz (Republic of North Ossetia-Alania) and a source of environmental pollution with lead, zinc and cadmium. Modeling of lead contamination of five types and subtypes of soils most closely lying to the metallurgical enterprise was carried out. The following of gross lead concentrations were established in soils in the area of the metallurgical enterprise: chernozem leached – 160 mg/kg, chernozem ordinary – 150 mg/kg, dark gray forest – 120 mg/kg, mountain-meadow soddy – 110 mg/kg, brown forest weakly unsaturated – 100 mg/kg.

In recent years, the spread of wildfires has increased in Russia and the world. Fires have a catastrophic impact on forest ecosystems, as well as a significant impact on the biota and biological activity of soils. In recent years, an assessment has been made of the enzymatic activity of brown soils in xerophytic forests of the Black Sea coast in the Caucasus after the impact of fires. The study area is located on the Abrau peninsula of the Black Sea coast in Russia in the Utrish State Natural Reserve. The xerophytic forests and woodlands, which are widespread there, consist of various species of junipers, oaks, pistachios, and other species; the soil cover is represented by a combination of brown soils with varying degrees of thicknesses, stoniness, and carbonate and humus contents. The studied postpyrogenic sites differ in different recovery periods (0–11 years). Soil samples were taken from three different depths (0–3, 3–10, and 20–30 cm) in triplicate. A significant, long-term effect of fires on the activity of enzymes (catalase, invertase, peroxidase, urease) in brown, subtropical soils has been shown. The content of organic carbon immediately after the fire in the surface horizon increases due to the accumulation of pyrogenic carbon ash, ash, and soot on the soil surface. A year after the fire, the carbon content in soils decreases by 47%, but it approaches the control values after 11 years. The activity of catalase, urease, and phosphatase in brown, postpyrogenic soils immediately after the fire was reduced by 43–69% in comparison with the soil of the control plot. The peroxidase activity, conversely, was stimulated by fire. The degree of enzyme inactivation and the change in the content of organic carbon in postpyrogenic soils subsequently depended on the time of postpyrogenic restoration of ecosystems and the enzyme type. Features of changes in enzyme activity during the restoration of postpyrogenic brown soils have been revealed. A complete recovery of the enzymatic activity of postpyrogenic brown soils did not occur even 11 years after the fire. A change in the correlations between the enzyme activity and the content of organic carbon in the soil in postpyrogenic brown soils of different ages is established.