Groups Of Soil Microorganisms Research Articles

Effects of pesticides on soil bacterial, fungal and protist communities, soil functions and grape quality in vineyards

Abstract Pesticides can have unintentional effects on non‐target organisms and change biotic communities. Such changes might be particularly important in soil microbial communities, which drive many ecosystem functions and may affect crop quality. Here, we investigated, in a three‐year study, how vegetation control (by herbicide application) and soil copper content (from long‐term copper‐based fungicide application) affect biodiversity and the community structure of soil bacteria, fungi and protists, and associated soil functions (respiration, decomposition) in Swiss vineyards. Furthermore, we determined the effects of these two management practices on grape quality as the most direct ecosystem service to farmers. Across all study years, the community composition of microorganisms was affected by herbicide application, however, a significant loss of operational taxonomic units (OTUs) was only observed in fungi and protists. Soil copper content reduced OTU richness of bacteria and protists in some years but had no significant effect on fungal richness. Copper changed the community composition in all three groups of soil microorganisms. While we found no effect of copper on soil functions, herbicide application reduced microbial respiration and biomass by about 39% and 45%, respectively. However, decomposition rates remained virtually unchanged by any pesticide. Yeast assimilable nitrogen (YAN) levels in grape were below the critical threshold of 140 mg/L in 40% of the vineyards without herbicide application and the variety Chasselas, whereas in vineyards with herbicide application, it was only 20%. Application of pesticides led to changes in richness and composition of soil microbial communities and directly reduced some soil functions (microbial biomass and respiration) but not all (decomposition). Some grape quality parameters can be indirectly enhanced by pesticide application, highlighting the trade‐off between the interests of nature conservation and the interests of the farmer. Balancing these two diverging interests requires the establishment of alternative vineyard management allowing reduced pesticide application.

Influence of firefighting fluorosynthetic film forming foam on soil microbocenosis

Per- and polyfluoroalkyl substances (PFASs) are a group of over 5000 different chemicals that are used in a wide range of industrial applications and consumer products. Perfluoroalkyl substances have unique properties, such as high chemical stability and surface activity, which leads to their widespread use in medicine, science and everyday life. Aqueous film forming foams (AFFFs) are complex proprietary formulations that contain percent levels of PFASs as well as solvents and hydrocarbon surfactants which, when combined, afford AFFF the functionality required for its purpose. Firefighting foams, such as AFFF, are used primarily to control fires involving flammable liquids such as fuel and oil. AFFF suppresses fire by producing a film over the fuel/oil fire that effectively starves the fire of oxygen. The carbon-fluorine bond makes these compounds extremely strong and stable. This chemical and thermal stability allows these substances to persist in the environment without breaking down. While biological effects of single PFAS have been studied, the effects of PFAS-containing mixtures, such as AFFF, are unknown. The environmental effects of firefighting foam pollutants are generally considered in terms of their toxicity and their biodegradability. Firefighting foams have been found to have a negative impact on the environment (e.g. can remove oxygen from aquatic environment in turn killing aquatic fauna). The effect of PFAS on the microorganisms is not sufficiently studied. To date, there are few studies on the structure and dynamics of microbes in the presence of per- and polyfluoroalkyl substances. Moreover, the results are contradictory. In this regard, it is important to study the impact of various PFAS chemicals on the microorganisms. The article presents the results of the effect study of a fluorosynthetic film forming foam, the main component of which is perfluorinated organic acid, on soil microorganisms, namely ammonifiers, oligonitrophils and nitrogen-fixing microorganisms, yeasts and molds, actinobacteria, and cellulose-degrading bacteria. It was accomplished by plating a sample of the soil that has been serially diluted in water and enumeration of colony forming units (CFU) per gram of soil. The number of soil microorganisms was counted two weeks and three months after contamination with a fluorosynthetic film forming foam. The control sample was unpolluted soil. The sample of soil (1.0 g) was mixed and suspended with a 10 ml of water in a tube for isolation and enumeration of microorganisms. The sample was shaken vigorously to separate organisms from the colloidal material surrounding soil particles. Obtained suspension was serially diluted from 10-2 to 10-6. Aliquot of each dilution was plated onto suitable agar medium. Meat-peptone agar, wort agar, starch-ammonia agar, ashby's agar and hutchinson's agar were used to isolate different groups of microorganisms from gray forest soil and to study the effect of film forming foam on them. The plates were incubated at 28 °C for 3–14 days and the results are expressed as CFU per gram of soil. Colonies of bacteria on meat-peptone agar and ashby's medium were counted after 3–4 days, yeasts and fungi on wort agar after 4–5 days and actinobacteria on starch-ammonia medium after 7–10 days. The number of colonies of cellulose-degrading microorganisms was counted after 14 days cultivation. Firefighting fluorosynthetic film forming foam led to the soil microbial community restructuring and a microbial diversity decrease. The study revealed a decrease the number of different groups of soil microorganisms two weeks after the pollution with the firefighting fluorosynthetic film forming foam, in particular ammonifiers by 2 times compared to the control, nitrogen-fixing microorganisms by 2.7 times, actinobacteria by 4.7 times, yeasts and fungi by 2.8 times. Three months after soil contamination with AFFF the number of nitrogen-fixing microorganisms, actinobacteria, yeasts and fungi increased by 1.85, 1.2 and 2.6 times compared to the control respectively. The number of ammonifiers and cellulose-degrading microorganisms decreased by 1.7 and 5.0 times compared to the control respectively.

Ways of Auxin Biosynthesis in Microorganisms

Among plant hormones, auxins, in particular indole-3-acetic acid (IAA), are the most studied and researched. Almost all groups of soil microorganisms, both plant-associated and non-plant-associated bacteria, fungi, and phytopathogenic microorganisms are capable of producing auxins. The development of preparations for crop production is directly related to the production of bacterial strains with high auxin-synthesizing potential, which is possible only with a full understanding of the ways of regulation and synthesis of auxins in bacteria. The synthesis of auxins in microorganisms can take place in two ways: by the gradual conversion of tryptophan to IAA (tryptophan-dependent pathway) or by the use of other intermediates (tryptophan-independent pathway). The latter is poorly clarified, and in the literature available today, there is only a small amount of information on the functioning of this pathway in microorganisms. The review presents literature data on the ways of auxin biosynthesis in different groups of microorganisms, as well as approaches to the intensification of indole-3-acetic acid synthesis. The formation of IAA from tryptophan can be carried out in the following ways: through indole-3-pyruvate, through indole-3-acetamide, and through indole-3-acetonitrile. The vast majority of available publications are related to the assimilation of tryptophan through the formation of indole-3-pyruvate as this pathway is the most common among microorganisms. Thus, it functions in rhizospheric, symbiotic, endophytic, and free-living bacteria. The concentration of synthesized IAA among natural strains is in the range from 260 to 1130 μg/mL. Microorganisms in which the indole-3-acetamide pathway functions are characterized by lower auxin-synthesizing ability compared to those that assimilate tryptophan through indole-3-pyruvate. These include bacteria of the genera Streptomyces, Pseudomonas, and Bradyrhizobium and fungi of the genus Fusarium. The level of synthesis of IAA in such microorganisms is from 1.17×10−4 to 255.6 μg/mL. To date, only two strains that assimilate tryptophan via the indole-3-acetonitrile pathway and form up to 31.5 μg/mL IAA have been described in the available literature. To intensify the synthesis of indole-3-acetic acid, researchers use two main approaches: the first consists in introducing into the culture medium of exogenous precursors of biosynthesis (usually tryptophan, less often indole-3-pyruvate, indole-3-acetamide, and indole-3-acetonitrile); the second — in increasing the expression of the corresponding genes and creating recomindolebinant strains-supersynthetics of IAA. The largest number of publications is devoted to increasing the synthesis of IAA in the presence of biosynthesis precursors. Depending on the type of bacteria, the composition of the nutrient medium, and the amount of exogenously introduced precursor, the synthesis of the final product was increased by 1.2—27 times compared to that before the intensifi cation. Thus, in the presence of 11 g/L tryptophan, Enterobacter sp. DMKU-RP206 synthesized 5.56 g/L, while in a medium without the precursor, it yielded only 0.45 g/L IAA. Recombinant strains Corynebacterium glutamicum ATCC 13032 and Escherichia coli MG165 formed 7.1 and 7.3 g/L IAA, respectively, when tryptophan (10 g/L) was added to the culture medium. The level of auxin synthesis in microorganisms may be increased under stress conditions (temperature, pH, biotic and abiotic stress factors), but in this case, the IAA concentration does not exceed 100 mg/L, and therefore this method of intensification cannot compete with the others above.

Effect of PhytoHelp and MycoHelp biopreparations on the soil microbiotes for soybean growing (Glycine max (L.) Merr.)

Ukraine ranks the second (out of 123 countries) in the exports of organic products to the EU according to the study of the organic market in 2019 conducted by the Information Center Green Dossier (OrganicInfo.ua), Organic Standard and the Research Institute of Organic Agriculture (FiBL). The official statistical reviews of IFOAM confirm that in 2018 there were about 510 organic farms in Ukraine, and the total area of the agricultural land on which the organic production is carried out was 429,100 hectares. Among the producers of organic products, more than 4.6% are involved in growing of the legumes. It should be noted that one of the main crops of the Fabaceae family grown in Ukraine is soybean (Glycine max (L.) Merr.). In recent years, there has been a significant increase in sown areas and soybean production, and the issue of its organic production is relevant. The aim of our research was to determine the effect of biological products based on bacteria: Bacillus subtilis, Azotobacter, Enterobacter and Enterococcus, on the main physiological groups of soil microorganisms in the cultivation of soybean plants. The research was conducted at the Institute of Agroecology and Environmental Management of the National Academy of Agrarian Sciences of Ukraine in the Department of Agrobioresources and Ecologically Safe Technologies in the laboratory and vegetative conditions. The soybean seeds of the Suzir’ya cultivar (selected by the National Research Center of the Institute of Agriculture of the NAAS) and Kent cultivar (selected by SAATBAULINZ, Austria) were treated with biological products produced by BTU Center: Phytocide (Bacillus subtilis, cell titer 1–4·109 CFU) cm3), PhytoHelp (B. subtilis — cell titer not less than 4·109 CFU) cm3), MycoHelp (B. subtilis, Azotobacter, Enterobacter and Enterococcus) according to the recommended doses. The methods prescribed in State Standard 7847:2015 was used to determine of the soil microorganisms and their associations. Statistical data processing was performed using the Microsoft Excel software package. The peculiarities of the influence of biological products based on bacteria: Bacillus subtilis, Azotobacter, Enterobacter and Enterococcus on the main physiological groups of soil microorganisms in the cultivation of soybean plants it has been demonstrate. It has been established that in the soybean and Kent soybean agrocenosis, MycoHelp and PhytoHelp biological products effect on the main ecological and trophic groups of soil microbiome, thereby increasing soil microbiological activity; significantly intensify the development of microorganisms that use mainly organic nitrogen compounds (in the system Kent variety — biological product MycoHelp this figure increased in 3.3 times, and at the variety Constellation — biological product PhytoHelp — in 5.3 — 18.8 times compared to the reference and control options, respectively). Root exometabolites of soybean varieties determine the nature and intensity of the impact of microorganisms on plants and lead to changes in the structure of microbial groups of the rhizosphere. In the system soybean variety Kent — biological product PhytoHelp the number of oligonitrophilic bacteria is significantly reduced (by 48.7%), and in the system — soybean variety Constellation — biological products both PhytoHelp and MycoHelp — remains unchanged. By optimizing the functioning of the system, after treatment of seeds with biological products, in the soil, in the system of soybean plants of the Kent variety, the number of inactive spore forms is reduced by 2.9–5.0 times, compared to the control; the processes of organic matter destruction are weakened and its synthesis is intensified in accordance with the values of the coefficients of oligotrophic, mineralization and immobilization of nitrogen and pedotrophic. It is proved that the use of biological products MycoHelp and PhytoHelp increases the efficiency of the plant system soybean — biological products.

The effect of the tank mixtures of humic substances and herbicides on the abundance of microbial communities in chernozem during chickpea cultivation

The effect of treatment of chickpea crops with chemical and biological plant protection agents on several groups of soil microorganisms was studied. Pesticides were used separately and in tank mixtures with humic substances. The treatment of plants with pesticides had a multidirectional effect on the numbers of microorganisms in the soil. It was found that the addition of humic substances to chemical pesticides increases the number of microorganisms in the soil, which is associated with its adaptogenic effect on plants. The use of tank mixtures of humic substances with pesticides on chickpea crops turned out to be most effective with second assortment of pesticides, but it was also effective with standard pesticides. For biological preparations, the opposite effect was observed: biological products were more effective without adding humic substances to them.

Identification of phosphate solubilizing fungi under Scaphium macropadum stands in Gunung Leuser National Park, North Sumatra

Scaphium macropadum is a wild tree species producing important timber and medicinal fruits. As a result of overexploitation, this species has decreased its population in the wild although categorized as least concern based on the IUCN red list of threatened species. Phosphate solubilizing fungi (PSF) are a group of soil microorganisms that can increase the availability and uptake of phosphorus (P) by plants. This study aims to isolate the phosphate solubilizing fungi from the soil under Scaphium macropadum stands following its morphological identification of species. Soil sampling was carried out randomly, with a depth of 0–20 cm under 12 stands of Scaphium macropadum in Gunung Leuser National Park, North Sumatra. Isolation of PSF was carried out using Pikovskaya medium with tricalcium phosphate (Ca3(PO4)2) as a source of inorganic P then the solubilization activity was expressed in the solubilization index (SI). The isolates obtained were identified morphologically to the genus level. The results obtained 15 isolates of PSF with SI ranging from 0.96 to 1.16. Based on the morphological identification, all isolates were identified as members of Aspergillus.

The suppression effect and mechanism of arbuscular mycorrhizal fungi against plant root rot.

Root rot is a serious soil-borne disease, with negative consequences on crop yield and quality. Arbuscular mycorrhizal (AM) fungi are a group of soil microorganisms, which play important physiological and ecological functions by establishing symbionts with plant roots. AM fungi could induce plant resistance against root rot by regulating physiological and biochemical processes. As a biological agent, AM fungi are used to antagonize soil-borne diseases such as root rot, which is a hotspot in the field of plant-microorganism interaction. We comprehensively reviewed the suppression effect of AM fungi on plant root rot, and the effect of AM fungi on root morphology of host plant, plant nutrition levels, as well as their role in competing with pathogens for ecological sites, activating plant defense systems, and regulating root exudates. Finally, we discussed the potential mechanism of AM fungi inhibiting root rot, as well as the practical problems in the efficient utilization of AM fungi were discussed, in order to provide the theoretical basis for the biological control protocol to antagonize root rot with AM fungi.

Мікробіологічна оцінка лучно-чорноземного карбонатного ґрунту за різних систем удобрення

Microorganisms play an important role in the formation of soil fertility, ensure their functioning as biological bodies of nature and are an indicator of qualitative soil changes. Due to the effect of anthropogenic activity on the soil there is a decrease in the number and depletion of the species composition of the microbiota. The aim of the research was to estimate the number of different physiological groups of microorganisms on meadow-chernozem carbonate soil under different fertilizer systems. Determination of the number of different groups of soil microorganisms was carried out according to the method of Zvyagintsev by sowing the soil suspension on solid nutrient media. It was established that the most favorable indicators of microbiocenosis and the highest yield of peas of Tsarevich variety were formed by the aftereffects of organic fertilizers and N45P45K45. The variant without fertilizers causes the development of mineralization of organic matter in meadow-chernozem carbonate soil by the content of pedotrophic and humatizing organisms and formed the lowest yield of peas. Application of only mineral fertilizers for growing peas formed a high rate of accumulation of humus at the level of Kak. = 1,6-1,9.

Microbiocenosis characteristics of agrogenically altered acid brown forest soils in humid subtropics of Russia

Under conditions of perennial cropping of industrial tea crop on acidic brown forest soils of the Black Sea coast of Russia, the following were investigated: number of bacteria, of actinomycetes (mainly the Streptomyces genus) and of micromycetes (saccharomycetes), seasonal dynamics and functional activity of the microbial complex during period of 2008-2019. Stationary experiments were launched in various backgrounds of mineral fertilizer application. The experiment was accompanied by the use of generally accepted recommended techniques for microbiological studies. As follows from the analysis of the data obtained, it was established that the long treatment period of mineral fertilizers at doses from N200P60K50 to N600P180K150 in given soil-climatic conditions under the tea crop contributed to significant decrease in the number of actinomycetes and nitrogen fixing bacteria of the Beijerinckia genus vs. the control variant (without fertilizers). The most significant decrease in the number of micromycetes was revealed immediately after the application of mineral fertilizers at a dose of N600P180K150. After 2 months, the number of this group of soil microorganisms was built back. Under the impact of both medium and high doses of mineral fertilizers, the functional activity decrease of soils (CO2 emission and potential nitrogen fixation activity) was noted.

Intraspecies variability of the 16S rRNA gene of the soil bacteria Acinetobacter lwoffii and Paenibacillus taichungensis

The functioning of well-studied key groups of soil microorganisms depends on the microbial ecosystem in which they function in interaction with species belonging to other ecological groups. An analysis of the composition of the soil microbiota, and the possibility of analyzing the number of representatives of specific species, remains an urgent task of soil microbiology. Such analysis could be performed using modern and expensive methods such as metagenomics and mass-spectrometry, but some questions could also be answered using real-time PCR. This well-known approach is rather cheap for massive analysis and is ready to present reproducible results for practical agricultural applications. Understanding the variability of the primary structure of 16S rRNA is key to the reliable identification of bacterial species and provides an opportunity to choose the optimal pathways for their detection by PCR. In this work, analysis of the sequences of 16S rRNA of two species of soil bacteria, Acinetobacter lwoffii and Paenibacillus taichungensis is carried out. The most variable and most conservative areas on the level of species are detected. It was proved that conventional variable and conservative areas of the gene have on average nearly the same level of variability on the intraspecies level.

Geoecological study of the soil microbial communities of the natural and agricultural ecosystems in the south-eastern Baltic sea region

ABSTRACT The number of different groups of soil microorganisms in the natural and agricultural ecosystems of the Kaliningrad Peninsula and the Curonian Spit was studied. It has been established that the studied ecosystems are distinguished by different types of soil, physicochemical parameters and the ratio of the main representatives of the soil microbial community: ammonifying microorganisms; microorganisms using mineral forms of nitrogen; nitrogen-fixing and oligonitrophilic microorganisms; cellulose-depleting microorganisms; aerobic spore-forming bacteria; microscopic fungi. The total content of different groups of microorganisms reflects the biological activity of the soil, which characterises its resistance and self-cleaning ability, which can be used in the study of modified soils under anthropogenic conditions.

Effect of management (ecological and conventional) on functional groups of soil microorganisms in coffee agroecosystems with different resilience to climate variability, Colombia

The effect of management (ecological and conventional) on functional groups of microorganisms of soil in agroecosystems with different resilience scores reported to climate variability in Anolaima, Colombia was evaluated. Were found clustering associated with management and cellulolytic bacteria and fungi abundances. No differences found in diversity of phosphate solubilizing or nitrogen-fixing microorganisms, related to management. The diversity of microbial functional groups was affected by the climatic condition of sampling season. Management was relevant in relationships between resilience scores to climate variability and cellulolytic microorganisms; in ecological agroecosystems, biodiversity knowledge, agroecological main structure, and the participation of farmers in organizations were important

Rehabilitation of the Biological Activity of the Soil Microbiota and the Structure of the Living Cover of the Soil under Technogenic Burden of the Extractive Industry

The article focuses on the features of the morphological, physical and chemical properties of the humus-accumulative embryo soils of nonfunctional stock heap of Mikhailovsky Mining and Concentrating Company (Mikhailovsky MCC). The biological activity of various groups of soil microorganisms: actinomycetes, microfungus and ammonifying saprophytes was studied. The types of plant communities of technogenic territory of overburden stock heap are identified, the main parameters describing the structure and dynamics of phytocenosis are described. It is established that the soils of key catena have high numbers of fungic microflora up to 145 thousand CFU / g in the gray-humus horizon, actinomycetes and ammonifiers have a low level of development. However, as relating to the previously obtained data, a general temporal tendency has been revealed, characterized by the increase in the biological activity and biomass of the groups under consideration, which is clearly observed in areas with soils rich in organic matter and mineral elements.

ВЛИЯНИЕ КОМПЛЕКСНЫХ УДОБРЕНИЙ НА БИОЛОГИЧЕСКУЮ АКТИВНОСТЬ МЕРЗЛОТНЫХ ПОЧВ

The results of studies of the biological activity of permafrost soils with the use of organic (rotted cattle manure in various doses of 20, 40, 60 t / ha) and mineral fertilizers (NPK)46 with the biological preparation Flavobacterin when growing potatoes are presented. The studies were carried out in a long-term multifactorial experiment in the period from 2016 to 2019. The soil of the experimental plot "Belentei" of the Yakutsk Research Institute of Agriculture, located on the territory of the Central Yakutsk lowland, the second above-floodplain terrace of the river. Lena, in the Khangalassky ulus (region) of the Republic of Sakha (Yakutia). The soil type of the experimental plot is permafrost chernozem-meadow light loamy saline. It has been established that the variants with the introduction of mineral and organic fertilizers, a biological product into the soil have a positive effect on the number of all groups of soil microorganisms (ammonifying, nitrite-forming, microscopic fungi), and increase by 2-6 times in comparison with control (without fertilizers). Intensive biological activity of permafrost soils in all years of research was noted during the growing season of potatoes. The number of soil microorganisms reached its maximum in July and decreased at the end of the growing season (early September), which is associated with the peculiarities of the hydrothermal regime of the studied soil. A relative assessment of changes in the biological properties of permafrost soil showed that the most intense biological processes are observed with the combined application of mineral and organic fertilizers and biological product ((NPK) 46 + Manure 20 t / ha + biological product "Flavobacterin") - 364%.

Do metal contamination and plant species affect microbial abundance and bacterial diversity in the rhizosphere of metallophytes growing in mining areas in a semiarid climate?

Mining areas are low-quality habitats for macro- and microorganisms’ development, mainly due to the degradation of the soil quality by metal pollution. The present work aimed to analyze the influence of metal contamination and of plant species on the rhizospheric microbial communities of four indigenous metallophytes (Ononis natrix, Haloxylon scoparium, Peganum harmala, and Aizoon canariense) growing along a metal contamination gradient in Kettara mine near Marrakech, Morocco. In pyrrhotite mining areas (Kettara mine, Morocco), rhizosphere soil samples were collected from four predominant indigenous metallophytes (O. natrix, H. scoparium, P. harmala, and A. canariense) growing along a metal contamination gradient (ZC, control zone; Z1, high metal contamination; Z2, moderate metal contamination; Z3, low metal contamination). Microbial communities were analyzed by using microbial counts and by denaturing gradient gel electrophoresis (DGGE). The physicochemical properties (pH, conductivity, total organic carbon, nitrogen, P Olsen, and metal concentrations) of soils were also determined. The physicochemical analysis revealed that rhizospheric soils from Z1, Z2, and Z3 were relatively poor in nutrients as they presented low levels of total organic carbon and nitrogen, organic matter and available P. Moreover, these rhizospheric soils showed high concentrations of metals, especially Cu and Pb, which significantly reduced the abundance of the different groups of soil microorganisms (bacteria, fungi, and actinomycetes) and the activity of soil dehydrogenase. The analysis of bacterial communities by DGGE revealed that bacterial diversity was not negatively affected by metal contamination being higher in the most contaminated area (Z1). Overall, the microbial abundance, the composition, and the diversity of rhizospheric bacterial communities were more influenced by the environmental factors in sampling zones than by plant cover. Microbial counts and enzymatic activity were both systematically affected throughout the metal gradient, evidencing as good indicators of the harmful effects of anthropogenic disturbances in soils. H. scorparium and P. harmala proved to be good candidates for the development of phytotechnological programs aiming the revegetation of mining degraded areas.

Мікробіологічна оцінка чорнозему реградованого за різних систем удобрення

Мікроорганізми відіграють дуже важливу роль у формуванні ґрунтів, забезпечуючи їх функціонування як біокосних тіл природи і є індикатором якісних змін ґрунту. Внаслідок антропогенного впливу відбувається зниження чисельності й збіднення видового складу мікробіоти. Досліджено зміни показників мікробіологічної активності чорнозему реградованого під впливом інтенсивної, маловитратної та органічної систем удобрення кукурудзи на зерно. Визначення чисельності різних груп ґрунтових мікроорганізмів проводилось за методикою Д. Г. Звягінцева посівом ґрунтової суспензії на тверді поживні середовища. Встановлено, що найбільш сприятливі показники мікробіоценозу були на варіанті з органічною системою удобрення. Як низький агрохімічний фон, так і варіант інтенсивної системи несприятливо впливали на процеси гуміфікації у чорноземному ґрунті за вмістом педотрофних і гуматрозкладаючих організмів. За інтенсивної технології встановлено посилення оліготрофності, що обумовлює конкуренцію за доступний азот між мікроорганізмами й рослинами. Кількість амоніфікуючих організмів за маловитратної системи була у 2,03 рази більше відносно інтенсивної та у 2,3 – відносно органічної системи, що свідчить про тенденцію до розкладу органічних речовин.

Isolation of Native Arbuscular Mycorrhizal Fungi within Young Thalli of the Liverwort Marchantia paleacea.

Arbuscular mycorrhizal fungi (AMF) are a group of soil microorganisms that establish symbioses with most land plant species. “Root trap culture” generally has been used for isolating a single regenerated spore in order to establish a monospecific, native AMF line. Roots may be co-colonized with multiple AMF species; however, only a small portion of AMF within roots sporulate, and do so only under certain conditions. In this study, we tested whether young thalli (<2 mm) of the liverwort Marchantia paleacea harbour monospecific AMF, and can be used as a vegetative inoculant line. When M. paleacea gemmae were co-cultivated with roots obtained from the field, the young thalli were infected by AMF via rhizoids and formed arbuscules after 18 days post-sowing. Ribosomal DNA sequencing of the AMF-colonized thalli (mycothalli) revealed that they harboured phylogenetically diverse AMF; however, new gemmae sown around transplanted mycothalli showed evidence of colonization from phylogenetically uniform Rhizophagus species. Of note, mycothalli can also be used as an inoculum. These results suggest that the young thalli of M. paleacea can potentially isolate monospecific AMF from field soil in a spore-independent manner.

Using a mixture of microalgae, biochar, and organic manure to increase the capacity of soil to act as carbon sink

Microalgae, biochar, or organic manure (OM) can be used as soil amendments to enhance soil organic carbon (OC) content. In the present study, a mixture of all three was used to test whether they could further improve soil OC content and the soil’s ability to retain and fix carbon. A laboratory incubation study was carried out to evaluate the efficacy of using microalgae, biochar, OM, or their mixture, as a soil amendment to improve OC in soil extract. Metabolic processes and soil microbial community structuring were analyzed to explore the mechanism by which the mixture increased the capacity of soil to act as a carbon sink. OC increased markedly (2.9 times its initial level) following the amendment of the soil with a treatment comprising microalgae, biochar, and the highest dose of OM. Microalgal metabolites were utilized by soil microorganisms as a carbon source. Biochar reduced the concentration of extracellular polysaccharides, whereas OM increased extracellular protein concentration. These metabolites affected the relative proportions of different groups of soil microorganisms, thereby increasing the proportion of Rhodobacter and Runella, which exerted a positive synergistic effect on soil OC and increased the soil’s capacity to fix carbon. A mixture including microalga, biochar, and OM as a soil amendment improved the OC of soil extract, and its effect was greater than that of any of its components alone. The findings of this study can help in devising ways to increase the OC content and the CO2-fixing capacity of the soil.

Influence of pre-sowing seed treatments with biologically active substances on spring wheat rhizosphere microbiocenosis

Aim of research. To evaluate changes in the spring wheat rhizosphere microbiocenosis at the pre-sowing treatment by citrates of biogenic metals, created based on nanotechnologies and inoculation of the consortium of root microorganisms in soil at the effect of these arrangements on the enzymatic activity of leaf tissues and productivity of wheat plants. Methods. Microbiological methods – inoculation on solid nutritive mediums for determining the content of main groups of soil microorganisms in the rhizosphere of plants; biochemical – for determining the activity of antioxidant enzymes of catalase and peroxidase; biometric – for determining the mass of 1000 seeds and seed productivity on experimental areas; statistical.Results of research. Field experiments of crops of spring wheat Pecheryanka demonstrate that at the pre-sowing treatment of seeds by 1%-solutions of biologically active substances in the content of composite fields of citrates of nanoparticles of Ag+Cu and Co+Cu+Zn+Fe+Mn+Mo+Mg (Avatar-1) and ions I-Se and introduction of the consortium of soil-useful microorganisms (biopreparation BP Extrakon), there were observed changes of ratios of main microbial groups in the composition of soil microbiocenocis: aerobic nitrogen-fixers, actinomycetes, fungal microflora, oligotrophic bacteria, that in some way correlated with the seed productivity.Conclusions. 1. It has been established, that the ratio of microbial groups, especially the percent of groups of aerobic nitrogen-fixers increased in the wheat rhizosphere relating to the control in the following succession – in the earing phase: BP Extrakon˃Extrakon+I-Se, and in the milk ripeness phase – in the following succession: BP Extrakon+I-Se˃BP Extrakon˃Avatar-1˃Ag-Cu. Actinomycetes prevailed on the variant with the pre-sowing treatment by I-Se, and the fungal microflora – in the milk ripeness phase. 2. The activity of catalase ad peroxidase in leaf tissues at the pre-sowing treatment by biologically active substances was lower than in the control, except the variant of the pre-sowing treatment by citrates of nanoparticles of Ag-Cu, where the catalase activity a bit grew – by 7.9%.3. It has been revealed, that indicators of the seed productivity improved most essentially at inoculation of the consortium of root microorganisms in soil, and also at the treatment that favored the increase of aerobic nitrogen-fixers in the soil rhizosphere, thus the seed productivity increased on the variants in the succession: BP Extrakon˃BP Extrakon+I-Se˃Avatar-1˃Ag+Cu, decreasing at the variant with the treatment by I-Se

Effects of different fertilizer systems and hydrothermal factors on microbial activity in the chernozem in Ukraine

Groups of microorganisms in soils perform the role of global biogeochemical membrane which provides metabolism of substances and energy between the pedosphere, lithosphere, hydrosphere and living organisms. Сlimate change has resulted in a complex combination of unpredictable changeability of the environment, which is a serious test for the stability and productivity for the natural and anthropogenically transformed ecosystems. Changeability of the hydrothermal factors causes serious changes in the structure and metabolic activity of soil microorganisms, the quality and properties of soil. We studied the impact of hydrothermal factors on the content of carbon, microbial biomass and organic substance in deep chernozem of a natural ecosystem (fallow) and an agroecosystem under different systems of fertilization of winter wheat. A close relationship (r = 0.69–0.79) was determined between the content of microbial biomass in soil and hydrothermal factors (air temperature and moisture). Excessive drought and high parameters of air temperature led to decrease in the content of microbial biomass by 1.5–2.8 times compared to the years with optimum parameters of hydrothermal regime (HTC = 1.0). Leveling out the impact of high temperatures on the productivity of the soil microbiota occurs at a sufficient amount of moisture, and also available nutrients. Drought (HTC = 0.4) and excessive moisture (HTC = 2.0) following heightened air temperatures reduce the release of СО2 from soil. Fallow soil usually has a high content of microbial carbon in the organic compounds of soil (Сmic/Сorg was 2%). In the agroecosystem, there was recorded a decrease by 26–32% of the Сmic specific share in the content of the organic compound of the soil compared to the natural analogue. With organic and organic-mineral systems of fertilization, an increase in Сmic/Сorg parameter occurs and the soil parameters become close to the soil of a natural ecosystem. The calculated ecological coefficients of the orientation of microbial processes in soil indicate a possibility of a balanced functioning of the microbial group and introducing organic and organic-mineral fertilizers, creating optimum conditions for the productivity of winter wheat.