Reclamation Methods Research Articles

Exploring non-thermal plasma technology for microalgae removal

The global population and economic development surge has substantially increased water demand, resulting in heightened sewage and pollutant generation, posing environmental hazards. Addressing this challenge necessitates the implementation of efficient and cost-effective water reclamation methods. Non-thermal plasma technology (NTP) has emerged as a promising solution, garnering attention for its superior efficiency compared to alternatives. While existing studies have predominantly focused on energy efficiency and pollutant removal, limited research has delved into the biological removal aspect, particularly concerning algae. This study utilized a dielectric barrier plasma diffuser to eliminate Spirulina microalgae (Spirulina platensis) from wastewater solutions, demonstrating higher algae removal and superior mass transfer compared to alternative plasma methods. The effect of sample volume, input voltage and power, flow rate, and initial solution concentration on the algae removal was investigated. Investigation of operational parameters revealed the best condition resulting in a 98 % removal rate and 20 g/kWh energy efficiency. The best conditions for the removal of Spirulina microalgae were considered in a sample volume of 50 mL, a voltage of 7.6 kV, a flow rate of 700 mL/min, and an initial solution concentration of 1280 mg/liter. Scanning Electron Microscope (SEM) images illustrated the impact of active species on cell structure, leading to the destruction of spiral form and loss of reproductive ability. The study underscores the potential of NTP for efficient algae removal and identifies key active species involved in the process. The removal of Spirulina microalgae was attributed to a combination of singlet oxygen (1O2), hydroxyl radicals, and ozone.

The Impact of Waste Application on the Reclamation and Biological Life of Degraded Soils

This work concerns the assessment of soil reclamation and its impact on biological life in areas destroyed by the sulfur industry in Jeziórko. Sulfur extraction using the borehole method causes enormous destruction to the soil environment. Among the many forms of degradation, the most pronounced are the chemical transformations of the environment and the disturbances in water relations in large areas, which could theoretically impact areas not within the direct range of the mining plant. This work aimed to assess the condition of biological life in soil reclaimed with waste in areas devastated by the sulfur industry in Jeziórko. The reclamation of these soils was difficult but necessary due to the complete disappearance of biological life. Appropriate actions were taken to restore and improve the properties of the soil, which resulted in an improvement in their production capacity. Reclamation was carried out, among other techniques, by deacidifying the soil using post-flotation lime and fertilizing the soil with municipal sewage sludge and post-use mineral wool. Studies have shown an improvement in many soil properties, such as its physical, water, chemical, and biological properties. The implemented reclamation methods significantly influenced, among other things, the density and water properties of the degraded soil. The soil reclaimed with mineral wool and sewage sludge recorded the highest density and water capacity. Applying mineral wool to the degraded soil influenced the changes in the analyzed physical and water properties. The obtained research results also show the beneficial effect of mineral wool and sewage sludge on the increase in organic carbon content. In the soil treated with these substances, the organic carbon content ranged from 13.60 g·kg−1 to 14.30 g·kg−1. It is shown that reclamation has had a considerable impact on and is essential for biological life in Jeziórko.

Soil organic carbon and nitrogen in a carboniferous spoil heap as a function of vegetation type and reclamation treatment

AbstractEvaluating the impact of vegetation types and reclamation methods on soil organic carbon and nitrogen in carboniferous spoil heaps is critical for selecting the best vegetation type and reclamation method to improve ecosystem services in a changing climate. This paper presents the relationship between vegetation types (woodland, forbland, and grassland) and reclamation techniques (barren rock, topsoil application, succession, and cultivation) on soil organic carbon (SOC) and total nitrogen (TN) in developing soils on carboniferous rocks in coal mine heaps. Soil samples were collected from the litter layer (Oi + Oe) and the A horizons (0–10 cm). The results revealed that vegetation types and reclamation methods significantly affected SOC and TN stocks. Woodland exhibited higher SOC and TN in the Oi + Oe horizons than other vegetation types. Topsoil application and cultivation resulted in the highest SOC and TN stocks in the A horizons (0–10 cm) under woodland and forbland compared to succession on bare carboniferous rock. In grassland, there was no significant difference in SOC stock under topsoil application and cultivation; however, significantly higher TN stock was observed in the 0–10 cm areas with topsoil application compared to succession on bare carboniferous rock. Based on the results, topsoil application is recommended to improve SOC if the mining site is restored using woodland. Conversely, grassland exhibits a similar amount of SOC stock with or without topsoil application. Considering the difficulty of obtaining topsoil, we suggest that grasses are optimal for SOC stock in the studied mining sites, followed by forbs.

Research on ecological restoration and green reclamation technology of goaf in phosphorus mines

The subsidiary of Yunnan Phosphate Group Co., Ltd., Kunyang Phosphate Mine’s mining area is the subject of study. The mining of open-pit phosphate mines has caused significant damage to the ecological environment. Therefore, carrying out ecological restoration and green reclamation of the ecosystem in the mining area has become the top priority for current development. This article establishes an evaluation system for ecological restoration indicators, selecting four indicators including vegetation coverage, soil and water conservation, restoration of native plants, and Plant Species Diversity Index to assess the effects of ecological restoration and green reclamation of phosphate mines. The techniques of reconstructing soil ecological structure using phosphate tailings substrate and improving acidic soil with soil conditioner and calcium-magnesium phosphate compound fertilizer were applied. A series of other measures were taken, including: drafting scientific ecological restoration plans; employing physical, chemical, and biological methods for ecological restoration and green reclamation; selecting suitable plant species for planting; enhancing planting techniques; and strengthening post-restoration ecological monitoring and regulation. After ecological restoration and green reclamation, the Ecological Remediation Effect Index (EREI) for the years 2020, 2021, and 2022 were 48.40, 87.38, and 93.23 respectively, indicating significant improvement in the ecological environment. Furthermore, the difficulties encountered during the ecological system restoration process of the mine and the future development directions were summarized, providing practical and guiding significance for ecological restoration and green reclamation of abandoned mining areas both domestically and internationally.

The efficient applications of native flora for phytorestoration of mine tailings: a pan-global survey.

Mine tailings are the discarded materials resulting from mining processes after minerals have been extracted. They consist of leftover mineral fragments, excavated land masses, and disrupted ecosystems. The uncontrolled handling or discharge of tailings from abandoned mine lands (AMLs) poses a threat to the surrounding environment. Numerous untreated mine tailings have been abandoned globally, necessitating immediate reclamation and restoration efforts. The limited feasibility of conventional reclamation methods, such as cost and acceptability, presents challenges in reclaiming tailings around AMLs. This study focuses on phytorestoration as a sustainable method for treating mine tailings. Phytorestoration utilizes existing native plants on the mine sites while applying advanced principles of environmental biotechnology. These approaches can remediate toxic elements and simultaneously improve soil quality. The current study provides a global overview of phytorestoration methods, emphasizing the specifics of mine tailings and the research on native plant species to enhance restoration ecosystem services.

Comparison of Saturated Hydraulic Conductivity under the Reclaimed Conditions of Salt Affected Soil

Solving the soil problems that affect negatively on growth of plants and reduce the soil permeability is necessary for the study site, Thein Gone Village in Yamethin Township, Myanmar. The objectives of this study were; to identify the soil whether it is salt-affected or not and to investigate the proper reclamation method with different rates of amendments by comparing the saturated conductivity (Ks). Both composite (disturbed) and core (undisturbed) soil samplings were collected at three profiles (0 - 60 cm soil depth) during March, 2023. Some soil properties such as texture, bulk density (g cm-3), moisture content (%), ECe (electrical conductivity, saturated extract; mS cm-1), pH (1:5 water), SAR (sodium absorption ratio) and pH and EC of leaching water were also measured. Firstly, the study site was problematic with high pH due to Na+ distribution of underground water although there was some application of gypsum for a decade. Also, low permeability (Ks < 1x10-8 cm s-1) was another problem there. To leach the salt (EC < 1 mS cm-1 in leachate), 1500 cm3 of water was necessary for one core (98.21 cm3 soil volume). It was relatively high amount for using the quality-water. For reclamation methods, gypsum 5 t ha-1, sulphur 1 t ha-1, and cow-dung manure 20 t ha-1 gave the minimum (- log Ks) value among different rates of each amendment. The less the - log Ks, the more permeable the soil becomes. Among different amendments, gypsum 5 t ha-1 showed the fastest saturated hydraulic conductivity. Moreover, it is necessary to drain out the leachate to prevent the formation of saline -sodic soil.

Analysis of Factors Affecting Vacuum Formation and Drainage in the Siphon-Vacuum Drainage Method for Marine Reclamation

Traditional drainage methods for marine reclamation typically consume large amounts of energy and have a negative environmental impact. The siphon-vacuum drainage method (SVD) automatically forms a vacuum and drains using less energy. It has significant potential for research and application. In this study, a theoretical model is used to calculate the vacuum formation process and drainage rate. Qualitative analysis and global sensitivity analysis were conducted to investigate the effect of various factors in the SVD on vacuum formation and drainage. The qualitative analysis suggests that modifying the length and diameter of the siphon pipe and the thickness of the sealing soil column to increase the siphon rate can improve the vacuum degree and drainage efficiency. Sobol global sensitivity analysis reveals that the sealing soil column thickness is the main factor affecting the vacuum, with a first-order sensitivity index accounting for up to 79.48%. The impact of cylinder diameter and the local resistance coefficient (0.43%) can be almost neglected. A fitting equation for estimating the maximum achievable vacuum is provided. Calculations show that the vacuum formed by the SVD can reach over 80 kPa. This work can help optimize SVD design and advance environmentally friendly marine reclamation projects.

Variation in soil characteristics of ex-coal mining areas in Sawahlunto, West Sumatra

Soil characteristics in ex-coal mining areas can be influenced by reclamation methods and the type and age of revegetation plants used. This reclamation can also significantly impact the soil chemistry of ex-mining areas. This research was conducted in ex-coal mining areas located in Parambahan, Batu Tanjung Village, Talawi District, Sawahlunto City, West Sumatra Province. The objective of this study is to analyze variations in the reclamation process and their effects on the chemical properties of soil in these areas. Observations were made in several plots, including land that had not been mined (natural forest), land revegetated with Acacia in the planting years of 1992, 2007, 2010 (without the use of topsoil), 2019, and 2021, and land revegetated with Sengon in 2022. In each plot, soil samples were collected at three depths: 0–5 cm, 5–10 cm, and 10–20 cm, to analyze soil chemical properties. These properties included pH, total nitrogen (N), available phosphorus (P), organic carbon (C), exchangeable base cations (K, Ca, Mg, and Na), cation exchange capacity, and exchangeable aluminum (Al). The results showed that variations in the years of revegetation and reclamation practices, such as the use of topsoil and plant types, significantly influenced soil chemical characteristics. The longer the period of revegetation, the better the improvement in the soil’s chemical properties, as indicated by changes in pH, total N, organic C, exchangeable K, Na, Ca, and Mg, cation exchange capacity, and a reduction in exchangeable Al. However, the availability of P, as indicated by available P, decreased after more than 30 years of revegetation.

"We Are Making Good under the Honor System": The Social Rehabilitation of Juvenile Males through Militarism, Moral Reform, and Enforced Work Routines at the British Columbia Boy's Industrial School, 1919–1934

Abstract: Industrial schools were the dominant mechanisms for the social rehabilitation of wayward juveniles in North America from the late nineteenth to mid-twentieth century. The research concerning such schools in shaping young lives is scattered within the historiography of youth. Girls were taught domestic skills and boys were trained in trades such as agriculture. Forced labor was not punishment but seen as moral uplift for troubled youth. This article studies the British Columbia Boy's Industrial School from 1919 to 1934 under David Blackwood Brankin, whose "honor system" combined discipline, strict work routines, regimented leisure, and a minimum of compulsory schooling. Brankin's court missionary work in Great Britain and military career shaped his vision of juvenile social rehabilitation until his retirement in 1934. His replacement was an educator trained in psychology and mental hygiene methods of youth reclamation.

The results of chemical reclamation of the soil component of natural and seeded meadows in the Non-Black Soil Zone of the Russian Federation

The reclamation role of the preparation Kovelos in relation to elements of the heavy metal group – copper and zinc - has been proven: a decrease in their gross concentration when applying a silicon-containing nanopreparation at a dose of 120 kg/ha is statistically significant. Thus, soil grassing in combination with the introduction of a silicon–containing preparation is an effective method of land reclamation in aerotechnogenic pollution areas. It was found that during the four-year period of meliorant application, OCC values in soils grassed with natural and seeded vegetation increased for 3 and 4 years of observation. The differences in the OCC fixation differ unreliably with the variants without the addition of nanosilicon, nevertheless, OCC reserves increase significantly. The range of OCC accumulation as a result of long-term use of chemical meliorant is as follows: caper euphorbia + oats > common timothy > cow clover > koeleria-red fescue > two-source > cow parsnip-foxtail. The use of synthetic amorphous silicon dioxide leads to cheaper reclamation methods, reduced labor and energy costs, the use of an affordable and cheap drug, and the action complexity.

Восстановление нарушенных земель в горных экосистемах

Introduction. The growing volumes of extraction, processing and transportation of minerals in Russia and the world contribute to an increase in disturbed lands, which actualizes the development of new approaches and methods for reclamation work. However, a clear structure of methods for restoring disturbed lands has not yet been developed. Hence the purpose of the work: to explore the world experience in the implementation of traditional and innovative approaches to the reclamation of disturbed lands in order to identify the most promising trends for further research. Materials and methods. The theoretical and methodological basis of the study are the scientific works of Russian and foreign scientists in the field of earth sciences, geo-ecology, physical chemistry, geo-botany and microbiology. Methods of the work are general scientific methods, such as dialectical, historical, analysis, synthesis, comparison, grouping, as well as systematic and empirical approaches. Results and discussion. The study substantiates the identification of two approaches: traditional and innovative; the author’s structure of methods for biological stage of reclamation work has been developed. The traditional approach is characterized by standard, but less effective, labor-intensive, and therefore expensive, methods of reclamation by using a fertile soil layer and potentially fertile rocks with the sowing of perennial grasses, trees and shrubs. An innovative approach is on agenda today. It can significantly reduce the cost of reclamation procedures due to the use of modern technologies and materials for restoring soil fertility and decontaminating pollutants. The innovative approach includes basic methods: 1. Algae; 2. Washing; 3. Bioremediation; 4. Sorbent-oriented. The study offers to improve the term «disturbed lands» in the regulatory field of the Russian Federation in order to take into account, along with the anthropogenic and natural factors. The structure of the disturbed lands of Russia is revealed in the context of the extraction of various types of minerals. Conclusions and offers. The article presents the results of the analysis of the world methodological experience in biological stage of reclamation work. It has been established that both in Russia and abroad, work is underway to improve the biological stage of reclamation. Attention is focused on the method of bioremediation and its sub-method of phytoremediation with the sorbent-oriented method, the combination of which, according to the authors, is of the greatest practical interest. It is revealed that the tasks of using local types of raw materials for the creation of composite sorbents are topical. The authors consider the creation of composite sorbents based on peat, as the most common raw material in Russia, to be a promising direction.

Salinization of irrigated agricultural lands in the Altai Territory

Introduction. The Altai Territory is the leader among the subjects of the Siberian Federal District in terms of the area of arable land, of which more than 80% is located in the zone of unstable moisture. Irrigation predominates among agricultural hydrotechnical land reclamation in the region. The area of irrigated land is 69 thousand hectares, of which almost 10 % have varying degrees of salinity in the root layer. Prolonged irrigation of land and non-compliance with irrigation technologies can lead to salinization of lands in irrigation systems. The purpose of the research: spatio-temporal assessment and clustering of salinization of irrigated lands in the context of municipal districts and agrochemical zones: steppe, forest-steppe and foothills. Material and methods. In Russia, all irrigation systems have uniform rules for collecting data on the state of land, conducting soil-salt surveys and laboratory processing of their results. The research material was observational data on the salt regime of lands in irrigation systems of the Altai Territory for 2013-2022, data from annual state monitoring of lands, information on irrigated lands and the technical condition of reclamation systems from the reclamation cadastre. The research methods were general scientific methods (analysis and synthesis), applied mathematical methods (regression and cluster analysis), scientific methods of hydraulic engineering agricultural reclamation. Results and discussion. Based on the reclamation cadastre data, an analysis of the state of irrigated agricultural land was carried out according to the degree of salinization. A model of the dynamics of the area of highly and very highly saline lands was constructed, statistical assessments of the quality of the model were checked, and the average rate of annual increase in the area of lands subject to salinity was determined. An analysis has been made of the most possible causes of salinization on irrigated lands, which include high levels and salinity of groundwater, high salinity of water used for irrigation. Calculations were carried out, among other things, for agrochemical zones: steppe, forest-steppe and foothills. The dynamics of areas with different groundwater levels, groundwater salinity and irrigation water were assessed. Based on data for the beginning of 2015 and 2022, a cluster analysis of the regions of the Altai Territory was carried out according to the degree of salinization of irrigated agricultural lands. The dynamics of changes in the number of regions and the area of irrigated land in clusters is analyzed. In conclusion, the calculation results are summarized and general conclusions are drawn about the dynamics and possible reasons for changes in the studied indicators. The results can be directly used by government authorities and organizations of the reclamation complex of the Altai Territory.

In Silico Characterization of Plant Salt Tolerance Promoting KDP Proteins from Alcaligenes xylosoxydans

Soil salinity stress is a detrimental factor in crops production. Conventional methods of soil management and reclamation have been proved useless. On the contrary, exploiting the inherent genes and mechanisms of halotolerant bacteria can bring revolution in agriculture. Present study was designed to characterize ATPase dependent protein complexes kdpFABC and kdpDE in a salt tolerant bacterium Alcaligenes xylosoxydans. This complex enables plants to endure the saline environmental conditions through enhancing the K+ ions influx. For characterization, protein sequences of three isoforms of kdpA, four of kdpB, two of kdpC and one of kdpE were retrieved from Uniprot database. These were analyzed via ProtParam tool, AlphaFold protein database and HDOCK server. Highest affinity for ATP molecule was observed in kdpB confirming its reported function of ATP hydrolysis. All documented proteins were found polar (except kdpE), alkaline (except one isoform of each kdpA and kdpB), thermostable, to exhibit complex 3D structure (except for kdpC and E) and in vitro stability. These properties of subunit proteins can be exploited to engineer the complex and produce osmotolerant transgenic plants

Methodological approach to determining promising “quarry cavities – backfill material” systems on the territory of Ukraine

The research is aimed at identifying promising “quarry cavities – backfill material” systems on the territory of Ukraine. Currently, the existing reclamation methods for quarry cavities do not provide for the earth’s surface level complete restoration. A number of industrial wastes, the accumulation of which is increasing rapidly, are potential backfill materials. An insufficiently studied and promising method for restoring the earth’s surface level is the formation of a backfill mass in quarry cavities, which can provide geomechanical stability. Nevertheless, in order to develop directions for backfilling, it is necessary to have information on the spatial distribution of quarry cavities and potential backfill materials on the territory of Ukraine, which is also insufficiently studied today. The paper forms and reveals a theoretical idea about the “quarry cavities – backfill material” systems. A number of important conditions for the harmonious existence and effective implementation of the specified promising systems are characterized. The methodology for creating the basis of an information-analytical map is presented, and the principles for determining and characterizing its main constituent elements are given. A new information-analytical map of the spatial location of potential backfill materials and formed quarry cavities on the territory of Ukraine has been created, on the basis of which possible “quarry cavities – backfill material” systems have been identified. It has been determined that today on the territory of Ukraine, for the earth’s surface level complete restoration, it is expedient to consider the formation of a backfill mass in quarry cavities in 12 districts, where there are promising “quarry cavities – backfill material” systems. The concept of a complete restoration development of the earth’s surface disturbed by mining operations in certain potential systems is possible under conditions of synergistic interaction between public authorities and private business. The practical result obtained is an important basis for creating an effective mechanism and effective measures for a complete restoration of the earth’s surface state, which will contribute to strengthening the international image of Ukraine as a responsible and environmentally conscious country.

Establishing peat-forming plant communities: A comparison of wetland reclamation methods in Alberta's oil sands region.

The Sandhill Wetland (SW) and Nikanotee Fen (NF) are two wetland research projects designed to test the viability of peatland reclamation in the Alberta oil sands post-mining landscape. To identify effective approaches for establishing peat-forming vegetation in reclaimed wetlands, we evaluated how plant introduction approaches and water level gradients influence species distribution, plant community development, and the establishment of bryophyte and peatland species richness and cover. Plant introduction approaches included seeding with a Carex aquatilis-dominated seed mix, planting C. aquatilis and Juncus balticus seedlings, and spreading a harvested moss layer transfer. Establishment was assessed 6 years after the introduction at SW and 5 years after the introduction at NF. In total, 51 species were introduced to the reclaimed wetlands, and 122 species were observed after 5 and 6 years. The most abundant species in both reclaimed wetlands was C. aquatilis, which produced dense canopies and occupied the largest water level range of observed plants. Introducing C. aquatilis also helped to exclude marsh plants such as Typha latifolia that has little to no peat accumulation potential. Juncus balticus persisted where the water table was lower and encouraged the formation of a diverse peatland community and facilitated bryophyte establishment. Various bryophytes colonized suitable areas, but the moss layer transfer increased the cover of desirable peat-forming mosses. Communities with the highest bryophyte and peatland species richness and cover (averaging 9 and 14 species, and 50%-160% cover respectively) occurred where the summer water level was between -10 and -40 cm. Outside this water level range, a marsh community of Typha latifolia dominated in standing water and a wet meadow upland community of Calamagrostis canadensis and woody species established where the water table was deeper. Overall, the two wetland reclamation projects demonstrated that establishing peat-forming vascular plants and bryophytes is possible, and community formation is dependent upon water level and plant introduction approaches. Future projects should aim to create microtopography with water tables within 40 cm of the surface and introduce vascular plants such as J. balticus that facilitate bryophyte establishment and support the development of a diverse peatland plant community.

The change in agrochemical parameters of light gray forest soil from the level of mineral nutrition against the background of the aftereffect of liming in the conditions of the Nizhny Novgorod region

Relevance. The modern level of agricultural production is inconceivable without the use of chemicals: lime, mineral fertilizers. Liming acidic soils with the introduction of mineral fertilizers are important methods of complex land reclamation. Excessive acidity of the medium is one of the main reasons for low productivity of agricultural crops.Methods. The research was carried out in a long-term stationary experiment in the Nizhny Novgorod region on light gray forest soil. The influence of various doses of mineral fertilizers on the background of lime aftereffect on the productivity of the crop rotation link and changes in the acidity and degree of saturation of the soil bases were studied. The experience was based on a two-factor scheme.Results. The article says that by 2022, the aftereffects of various studied lime doses do not affect changes in the level of productivity of fodder crops of the crop rotation link: vicа-oats (vicоoats) + clover — clover 1 g. p. — clover 2 g. p. — clover 3 g. р. The total productivity is 19.6–20.8 t/ha by the factor of lime application in 1978. The greatest productivity of the studied crop rotation link is provided by triple doses of mineral fertilizers (24.4 t/ha by the standard), double and single doses provide the level of productivity of the crop rotation link in 20.0–20.1 t/ha by the standard, the cultivation of forage crops according to the natural agrophone provides a productivity level of 17.2 t/ha k. е.The applied lime doses, when laying the experiment, by 2022 do not affect the changes in agrochemical (exchange, hydrolytic density and the degree of saturation of the soil with bases) indicators in the twenty-centimeter soil layers. The use of triple and double doses of mineral fertilizers contributes to acidifying the soil compared to options without the use of mineral fertilizers and single doses.

Composition and assembly mechanisms of prokaryotic communities in wetlands, and their relationships with different vegetation and reclamation methods

Coastal wetlands are undergoing substantial transformations globally as a result of increased human activities. However, compared to other ecosystems, diversity and functional characteristics of microbial communities in reclaimed coastal wetlands are not well studied compared to other ecosystems. This is important because it is known that microorganisms can play a crucial role in biogeochemical cycling within coastal wetland ecosystems. Hence, this study utilized the high-throughput sequencing technique to investigate the structure and assembly processes of microbial communities in reclaimed coastal wetlands. The results revealed a substantial change in soil properties following coastal wetland reclamation. Remarkably, the reclaimed soil exhibited significantly lower pH, soil organic carbon (SOC), and total salinity (TS) values (p < 0.05). The dominant phyla included Proteobacteria, Chloroflexi, Bacteroidetes, Acidobacteria, and Planctomycetes among study sites. However, the relative abundance of Proteobacteria increased from un-reclaimed coastal wetlands to reclaimed ones. The Proteobacteria, Chloroflexi, and Acidobacteria showed higher relative abundance in vegetated soil compared to bare soil, while Bacteroidetes and Planctomycetes exhibited the opposite trend. Notably, vegetation types exerted the strongest influence on microbial diversity, surpassing the effects of soil types and depth (F = 34.49, p < 0.001; F = 25.49, p < 0.001; F = 3.173, p < 0.078, respectively). Stochastic assembly processes dominated in un-reclaimed soil, whereas deterministic processes governed the assembly in artificial sea embankment wetlands (SEW). The presence of Spartina alterniflora in all soil types (except SEW soils) indicated stochastic assembly, while Phragmites australis in reclaimed soils pointed toward deterministic microbial assembly. Furthermore, environmental factors such as pH, soil water content (SWC), SOC, total carbon (TC), total nitrogen (TN), total phosphorus (TP), NH4+-N, vegetation types, soil depth, and geographic distance exhibited significant effects on microbial beta diversity indices. Co-occurrence network analysis revealed a stronger association between taxa in SEW compared to land reclaimed from wetlands (LRW) and natural coastal wetlands (NCW). The bottom soil layer exhibited more complex network interactions than the topsoil layer. Besides soil parameters, reclamation and varieties of vegetation were also substantial factors influencing the composition, diversity, and assembly processes of microbial communities in coastal wetlands.

Geochemical and Microbiological Composition of Soils and Tailings Surrounding the Komsomolsk Tailings, Kemerovo Region, Russia

Microorganisms have the potential to address environmental pollution, but the interaction mechanism between microorganisms and mine tailings is not well understood. This work was aimed at determining the bacterial isolates in soils and mine tailings and evaluating the distribution of metals, antimony (Sb), and arsenic (As) in the soils around the Komsomolsk tailings. Areas with high concentrations of As, Sb, cadmium (Cd), and lead (Pb) were found. Assessment based on the value of the contamination factor (CF) indicated large-scale As, Sb, Pb, Cd, iron (Fe), bismuth (Bi), and beryllium (Be) pollution, especially in soils sampled from the northeast direction of the mine tailings. Soils had a higher number of CFUs per g of dry weight than did the tailings, ranging from 84 × 106 to 3.1 × 109 and from 20 × 106 to 1.7 × 109, respectively. Arsenic exhibited a positive statistical correlation with the number of CFUs of Agrococcus and Staphylococcus. In addition, a positive correlation was found between the concentration of Co and the number of CFUs of Moraxella and Microbacterium. The Sb exhibited a positive correlation with Streptomyces. These results can be used to develop methods for waste reclamation, including the use of isolated bacterial strains for arsenic removal by precipitation.

Эколого-биологические аспекты кустарниковой мелиорации деградированных пастбищ на бугристо-увалистых комплексах песчаных земель Прикаспия

The article presents the results of studies of the effectiveness of shrub reclamation on pastures of the Caspian Sea. Introduction. As a result of the outbreak of deflationary desertification of lands that occurred on the territory of the Russian Caspian Sea in the 70-80-ies of the XX century, it became necessary to develop methods for large-scale shrub reclamation of degraded lands. One of the problematic areas where these works were carried out is pastures on light soils of the Astrakhan Volga region. Materials and methods. The study is based on biomonitoring materials and field experiments using standard methods of forest taxation, soil science and geo-botany. Results and discussion. Thanks to the microclimate, the best conditions for the growth of herbaceous vegetation are formed in the spaces between pasture-protective strips with a width of 30 m. The yield of herbage phyto mass on them, both in spring and autumn, is higher by 0.06–0.13 t/ha. With severe damage or destruction of shrub plantations, areas with productive herbage degrade. Reclamation and forage plantations, depending on the age, increase the yield of pastures by 41–85%. The productivity of herbage is everywhere higher on pastures with a complex of pasture-protective and reclamation-forage plantations with teresken at the age of 20-25 years. Сonclusion. It has been established that pasture protection strips from haloxylon, reclamation and fodder plantations from krascheninnikovia and calligonum in the Astrakhan Volga region have been functioning for more than 45 years. It was determined that in forested areas, depending on age, the preservation of saxaul is 14–45% with an average plant height of 2.0–3.2 m. It is shown that the plantings of krascheninnikovia and calligonum on hollow-bumpy and withered plains with light soils at the age of 30–40 years have a safety of 45–70%, have a positive effect on the restorative succession of herbage between rows of shrubs and in the wind-shade zones of strip and backstage plantings. It was revealed that the addition to the pasture forage in the form of an available twig-leaf mass of shrubs in May – August can reach 0.5–4.0 t/ha in dry form. The hay yield of natural forage vegetation under the protection of shrub plantations on improved pastures is 1.2–1.5 times higher compared to unprotected lands and amounts to 0.70–1.60 t/ha. The results of the research can be useful in the phyto-melioration of degraded pastures located on bumpy sandy lands. Suggestions for practical application and direction of future research. The results of the research can be useful in the phytomelioration of degraded pastures located on bumpy sandy lands. An urgent problem remains the development of a system of measures for the care, repair and reconstruction of shrub plantations that can increase their productivity and durability on functioning pastures.

Effects of coal-derived compound fertilizers on soil bacterial community structure in coal mining subsidence areas.

The land damaged by coal mining can be recovered to healthy condition through various reclamation methods. Fertilization is one of the effective methods to improve soil fertility and microbial activity. However, the effects of coal-derived compound fertilizers (SH) on bacterial communities in coal mining subsidence areas still remain unclear. Here, we studied the effects on the nutrient characteristics and bacterial communities in fertilizer-reclaimed soil (CK, without fertilizer; CF, common compound fertilizers; SH, coal-derived compound fertilizers) in coal mining subsidence areas and we applied SH with four different nitrogen application rates (90, 135, 180, and 225 kg/hm2). The results showed that the application of SH significantly increased the contents of available nitrogen (AN), available phosphorus (AP), available potassium (AK), total phosphorus (TP) and soil organic matter (SOM) compared with CK, as well as the bacterial richness (Chao1) and diversity (Shannon) in reclaimed soil that increased first and then decreased with the increase of nitrogen application. Under the same nitrogen application rate (135 kg/hm2), the nutrient content, Chao1 and Shannon of SH2 treatments were higher than those of CF treatment. Meanwhile, SH increased the relative abundance of Proteobacteria, Actinobacteria and Gemmatimonadetes. LEfSe analysis indicated that the taxa of Acidobacteria and Actinobacteria were significantly improved under SH treatments. Canonical correspondence analysis (CCA) and Variance partitioning analysis (VPA) showed that SOM was the most important factor affecting the change of bacterial community structure in reclaimed soil. In conclusion, application of SH can not only increase nutrient content and bacterial diversity of reclaimed soil, but also improve bacterial community structure by increasing bacterial abundance.