Nitrogen Fixation Activity Research Articles

The presence of silver nanoparticles reduces demand for dissolved phosphorus to the benefit of biological nitrogen fixation in the coastal eastern Mediterranean Sea

The release of silver into the marine environment is of growing concern as its impact on marine life is not fully understood. Despite previous experiments that have shown toxic effects of silver as nanoparticles (AgNPs) and as free ions (Ag+) on microbial organisms, the impact on important biogeochemical processes, such as marine nitrogen fixation, remains relatively unexplored. The present study investigated the impact of AgNPs and Ag+ on nitrogen fixation activity in oligotrophic coastal ecosystems. Nine mesocosm enclosures were set-up in Crete, Greece, for twelve days during May 2019. Three mesocosms were left unamended at ambient light and temperature; three were manipulated with 50 ng AgNPs L-1d-1 and three were amended with 50 ng Ag+ L-1d-1. Over the duration of the experiment, mean nitrogen fixation rates proved higher in treated waters; 0.28 ± 0.24 nmol N L-1d-1 and 0.21 ± 0.19 nmol N L-1d-1 in AgNP and Ag+ which were 2.2 (p< 0.001) and 1.6 (not significant) times higher than control rates of 0.13 ± 0.07 nmol N L-1d-1 respectively. Changes in nitrogen fixation rates were paralleled by significantly higher concentrations of phosphate and silicate in treated versus control mesocosms, suggesting an inhibition of the uptake of these nutrients by non-diazotrophic groups. Sequencing of 16S and 18S rRNA genes showed shifts in community composition over time but only very minor changes could be linked to the Ag treatments. Decreases to the relative abundance of three diatom species were observed in the Ag treatments but these were considered insufficient to support the relative differences in nutrient concentration. It is therefore speculated that there was physiological disruption of nutrient uptake mechanisms of the non-diazotrophic community. A number of potential diazotrophs were detected and the relative sequence abundance of a number of known nitrogen fixing taxa, including Burkholderiaceae, Oceanospirillales and Pseudomonadales correlated with measured nitrogen fixation rates. Phosphorus limitation of diazotrophic activity was therefore lowered relative to other microbial groups in silver amended treatments and significant increases in particulate nitrogen for both Ag treatments indicate an enhancement in cellular N for the nitrogen fixing communities.

Cracked spindle morphology of MIL-101(Fe) for improved photocatalytic nitrogen reduction

Morphology regulation is a simple way to improve photocatalytic activity. In this work, a MIL-101(Fe) photocatalyst with cracked spindle morphology has been successfully prepared by EG pre-coordination solvothermal method. The cracking degree of MIL-101(Fe) can be regulated by adjusting pre-coordination time. The MIL-101(Fe) with the optimal uniform crack displays a best NH3 evolution rate of 592 ​μmol ​h−1 ​g−1 under the visible light irradiation. Cracked MIL-101(Fe) is similar to a semi-exposed model, which can increase the number of reactive sites, improve refraction and reflection of light, and ultimately enhance the photocatalytic nitrogen fixation activity. This work developed a convenient strategy to improve the photocatalytic activity of nitrogen reduction by controlling morphology.

PLANT GROWTH-PROMOTING TRAITS OF ANTARCTIC ENDOPHYTIC BACTERIA

Successful colonization of Antarctic lands by vascular plants Deschampsia antarctica and Colobanthus quitensis and their adaptation to stressful environments is associated not only with climate change but also with the functioning of microbial groups of phylo- and endosphere of these plants. The aim of our study was to screen plant growth-promoting traits in endophytic bacteria of antarctic vascular plants. Materials and methods. We have studied 8 bacterial cultures isolated from D. antarctica collected during the 25th Ukrainian Antarctic Expedition (January-April 2020) along the Western part of the Antarctic Peninsula. Overnight liquid cultures were obtained on Nutrient Broth medium (HiMedia, Ltd.) in a shaking incubator (26 ℃, 160 rpm). Bacterial isolates were grown on Ashby's combined-nitrogen-free medium with sucrose. Drop collapse assay for cyclic lipopeptide production (CLP), motility assay, exoprotease production and phosphate solubilizing ability were performed using generally accepted methods. Results. All studied isolates have shown plant growth-promoting traits. The most abundant were nitrogen-fixing activity and motility. Both these play important role in plant colonization and promoting the growth of plants in harsh environments. The evidences of CLP were shown by two strains only. There was no notice of phosphate solubilizing ability and exoprotease production. Conclusions. Endophytic bacteria of antarctic vascular plants could support the growth and nutrition needs of the plants.

Isolation, in vitro evaluation and construction of Versatile Microbial Consortia.

In this study, we constructed versatile microbial consortia (VMC) with agricultural and environmental interest. After sample and isolation procedure, the purified isolates were evaluated for their enzymatic potential such as cellulose-, xylan-, petroleum-, proteins -hydrolysis. Selected isolates were screened for other traits such as phosphate solubilization, nitrogen fixation and antimicrobial activity. Finally, the isolates were grouped into consortia according to their compatibility. The microorganisms selected for each consortium were identified by partial analysis of the 16S rRNA (bacteria) and the ITS region of the 18S RNA gene (fungi). Two microbial consortia were obtained and named VMC1 and VMC2. These two consortia are characterized by several activities of agricultural and environmental interest such as the degradation of recalcitrant and polluting organic compounds, nitrogen fixation, IAA production phosphate solubilization and antimicrobial activity. Molecular identification of the microorganisms forming the two consortia allowed us to identify two species of actinomycetes (Streptomyces sp. BM1B and Streptomyces sp. BM2B), one species of Actinobacteria (Gordonia amicalis strain BFPx) and three fungal species (Aspergillus luppii strain 3NR, Aspergillus terreus strain BVkn and Penicillium sp. BM3). The term "Versatile Microbial Consortia" is a term that we proposed in this study to establish a methodology for building multifunctional microbial groups for wide and efficient application.

Biological control and plant growth promotion properties of Streptomyces albidoflavus St-220 isolated from Salvia miltiorrhiza rhizosphere.

Root rot disease caused by Fusarium oxysporum is a devastating disease of Salvia miltiorrhiza and dramatically affected the production and quality of Sa. miltiorrhiza. Besides the agricultural and chemical control, biocontrol agents can be utilized as an additional solution. In the present study, an actinomycete that highly inhibited F. oxysporum was isolated from rhizosphere soil and identified as based on morphological and molecular characteristics. Greenhouse assay proved that the strain had significant biological control effect against Sa. miltiorrhiza root rot disease and growth-promoting properties on Sa. miltiorrhiza seedlings. To elucidate the biocontrol and plant growth-promoting properties of St-220, we employed an analysis combining genome mining and metabolites detection. Our analyses based on genome sequence and bioassays revealed that the inhibitory activity of St-220 against F. oxysporum was associated with the production of enzymes targeting fungal cell wall and metabolites with antifungal activities. Strain St-220 possesses phosphate solubilization activity, nitrogen fixation activity, siderophore and indole-3-acetic acid production activity in vitro, which may promote the growth of Sa. miltiorrhiza seedlings. These results suggest that St. albidoflavus St-220 is a promising biocontrol agent and also a biofertilizer that could be used in the production of Sa. miltiorrhiza.

Nitrogen content and C/N ratio in straw are the key to affect biological nitrogen fixation in a paddy field

Straw amendment can increase nitrogen fixation in paddy field, however, the efficiency of carbon sources with different biochemical properties to enhance N2 fixation and nitrogen fixation activity is still unclear. A 15N2-labelling system was used in the field environment to determine biological nitrogen fixation (BNF) under the addition of three kinds of straw. The nifH gene (DNA) and nifH RNA gene (cDNA) of soil were amplified by real-time fluorescent quantitative PCR. The diversity and community composition of nitrogen fixing microorganisms were studied by high-throughput sequencing. The study is expected to reveal how different carbon sources impact biological nitrogen fixation and its mechanism in the paddy field system. Results showed that the absolute abundance diazotrophs in the treatment of mature stage wheat straw (MWS) was 4.88 times as high as that in the CK treatment, but jointing stage wheat straw (JWS) and poplar branch (PB) did not induce any significant changes. Straw amendment had no impact on cyanobacteria abundance. The proportion of N2 fixation increased by MWS was 2.07 times, but which was much lower than the increase proportion of the heterotrophic diazotrophs, leading to a decrease of diazotrophic nitrogen fixation activity. Mature wheat straw addition increased biologically fixed nitrogen in paddy field by increasing the number of heterotrophic nitrogen fixing bacteria. The results indicated that to increase biological N2 fixation in paddy system, straws with low nitrogen content and high C/N ratio were recommended.

Polarized Cu-Bi Site Pairs for Non-Covalent to Covalent Interaction Tuning toward N2 Photoreduction.

A universal atomic layer confined doping strategy is developed to prepare Bi24 O31 Br10 materials incorporating isolated Cu atoms. The local polarization can be created along the CuOBi atomic interface, which enables better electron delocalization for effective N2 activation. The optimized Cu-Bi24 O31 Br10 atomic layers show 5.3× and 88.2× improved photocatalytic nitrogen fixation activity than Bi24 O31 Br10 atomic layer and bulk Bi24 O31 Br10 , respectively, with the NH3 generation rate reaching 291.1µmol g-1 h-1 in pure water. The polarized Cu-Bi site pairs can increase the non-covalent interaction between the catalyst's surface and N2 molecules, then further weaken the covalent bond order in NN. As a result, the hydrogenation pathways can be altered from the associative distal pathway for Bi24 O31 Br10 to the alternating pathway for Cu-Bi24 O31 Br10 . This strategy provides an accessible pathway for designing polarized metal site pairs or tuning the non-covalent interaction and covalent bond order.

Nitrogen Fixation Activity and Genome Analysis of a Moderately Haloalkaliphilic Anoxygenic Phototrophic Bacterium Rhodovulum tesquicola

The genome of the moderately haloalkaliphilic diazotrophic anoxygenic phototrophic bacterium Rhodovulum tesquicola A-36sT isolated from an alkaline lake was analyzed and compared to the genomes of the closest species Rhodovulum steppense A-20sT and Rhodovulum strictum DSM 11289T. The genomic features of three organisms are quite similar, reflecting their ecological and physiological role of facultative photoheterotrophs. Nevertheless, the nitrogenase activity of the pure cultures of the studied bacteria differed significantly: the highest rate (4066 nmoles C2H2/mg of dry weight per hour) was demonstrated by Rhodovulum strictum while the rates in Rhodovulum tesquicola and Rhodovulum steppense were an order of magnitude lower (278 and 523 nmoles C2H2/mg of dry weight per hour, respectively). This difference can be attributed to the presence of an additional nitrogenase operon found exclusively in R. strictum and to the structural variation in nitrogenase operon in R. tesquicola.

Arsenic Mobilization and Transformation by Ammonium-Generating Bacteria Isolated from High Arsenic Groundwater in Hetao Plain, China.

Arsenic (As) mobilization in groundwater involves biogeochemical cycles of carbon, iron, and sulfur. However, few studies have focused on the role of nitrogen-metabolizing bacteria in As mobilization, as well as in the transformation between inorganic and organic As in groundwater. In this study, the nitrogen and As metabolisms of Citrobacter sp. G-C1 and Paraclostridium sp. G-11, isolated from high As groundwater in Hetao Plain, China, were characterized by culture experiments and genome sequencing. The results showed Citrobacter sp. G-C1 was a dissimilatory nitrate-reducing bacterium. The dissimilatory nitrate reduction to ammonia (DNRA) and As-detoxifying pathways identified in the genome enabled Citrobacter sp. G-C1 to simultaneously reduce As(V) during DNRA. Paraclostridium sp. G-11 was a nitrogen-fixing bacterium and its nitrogen-fixing activity was constrained by As. Nitrogen fixation and the As-detoxifying pathways identified in its genome conferred the capability of As(V) reduction during nitrogen fixation. Under anaerobic conditions, Citrobacter sp. G-C1 was able to demethylate organic As and Paraclostridium sp. G-11 performed As(III) methylation with the arsM gene. Collectively, these results not only evidenced that ammonium-generating bacteria with the ars operon were able to transform As(V) to more mobile As(III) during nitrogen-metabolizing processes, but also involved the transformation between inorganic and organic As in groundwater.

Pseudomonas fluorescens BsEB-1: an endophytic bacterium isolated from the root of Bletilla striata that can promote its growth

ABSTRACT An endophytic Pseudomonas fluorescens (BsEB-1) was obtained from the roots of Bletilla striata. We investigated its growth-promoting properties and observed the impact of its inoculation on both the growth and polysaccharide content of Bletilla striata tubers. It was found that BsEB-1 possessed three growth-promoting activities: phosphate-solubilizing, produced indoleacetic acid (IAA) and siderophores, but had no nitrogen-fixing activity. BsEB-1 could rapidly attach to the root hairs of Bletilla striata tissue culture seedlings and endophytically colonize the region of maturation in the roots. It also significantly promoted the rooting and transplant survival rate of the seedlings, as well as the growth and expansion of the tubers, but did not increase their polysaccharide content. Pseudomonas fluorescens BsEB-1 exhibits potential for applications in the artificial planting of Bletilla striata.

Effect of organic fertilizers based on chicken manure on oat productivity and microbiological indicators of the soil

The results of studying the effect of preparations based on chicken manure on the growth and development of oats are presented. Chicken manure contains valuable substances that are easily used by plants, but because of the large number of pathogens, its use can lead to pollution of the environment. Currently, a promising direction is the use of poultry manure after additional treatment. Recycled chicken manure was used in the research using a cavitation-vortex heat generator by distilling dry manure as a 10% solution in water and obtaining various fertilizer samples. The manure was treated at different thermal regimes - 60 and 75 °C, with or without ozone. The effect of organic fertilizers based on chicken manure on soil biological activity and productivity of oats was studied. Numbers of the main groups of microorganisms were established by the conventional method of seeding on nutrient dense media. Soil phytotoxicity was determined according to the test-object recommendations. Oat growth and development were studied during the vegetation period, evaluating the onset of phenological phases, biometric indicators and elements of yield structure. A negative effect of chicken manure on the microflora (the appearance of conditionally phytopathogenic fungi) and phytotoxicity of soil, as well as on the condition of cultivated plants was revealed. The manure processed by distillation into organic fertilizer improves the environmental situation. A positive effect of organic fertilizers based on poultry manure on the phytosanitary state of the soil and nitrogen-fixing activity of the soil was found. An increase in productivity of oats was noted on the background of the application of organic fertilizers. There was a significant increase in green mass and dry matter in the flowering phase of oats by 6.0-6.2 and 1.1-1.7 tons/ha, respectively. Oat grain yield was higher by 0.7-0.8 t/ha, or 20%, compared to the control.

A system investigation on Ru-MOF-74 with efficient photocatalytic nitrogen fixation performance

Developing highly efficient photocatalysts for nitrogen fixation into ammonia is of great importance for solving the energy crisis and sustainable development. In this work, we report a simple synthesis of Ru3+ ions modified MOF-74 nanostructures. These Ru3+ ions are introduced into the internal channels of MOF-74 structure. The photocatalytic activity of nitrogen fixation was remarkably improved under visible irradiation (λ > 400 nm). After the introduction of Ru3+ ions, the visible response is enhanced and the photo-excited charge carriers are separated and transferred to the surface efficiently, leading to an improved photocatalytic performance. This work may offer a better understanding for designing and developing MOFs photocatalysts with high performance and low cost.

Light-Switchable Oxygen Vacancies Enhanced Nitrogen Fixation Performance on BiOBr: Mechanism of Formation, Reconversion and Function

Although BiOBr has been demonstrated to be a promising photocatalyst for the synthesis of ammonia, it still remains challenging to the recombination of photoproduction carriers and how to cleave the strong N≡N bond effectively. Herein, we report light-switchable oxygen vacancies (OVs) on BiOBr by a facile one-step alcoholysis method with excellent photocatalytic nitrogen fixation activity. The BiOBr with light-switchable OVs uplift the conduction band position, afford more active sites to activate N≡N, and promote the charges separation, thus the NH4+ yield rate reaches 246 µmol‧g−1‧h−1 under mild conditions. Meanwhile, in order to explore the formation and reconversion mechanism of light-switchable OVs, DFT calculation and Raman spectroscopy were used to reveal the essential phenomenon of BiOBr sample, and the photoelectrochemical characterizations were also employed to analyze the samples. Results prove that light-switchable OVs are created by dislodging the O atoms to form H2O molecules under light irradiation due to the high-density O atoms exposure and weak Bi-O bond in BiOBr. Furthermore, the light-induced OVs will be refilled by seizing the O atoms from O2 after turning off the light, leading to a fine recovery of the origin stable OV-free composition. This work provides a practical new strategy of light-switchable OVs formation for the development of catalysts with enhanced nitrogen fixation rate under mild conditions.

Symbiotic and physiological indicators of soybean inoculated of Bradyrhizobium japonicum single-strain in 7 days before sowing

Results of investigation of soybean of the Almaz variety in inoculation with preparations based on nodule bacteria Bradyrhizobium japonicum (Kirchner, 1896), Jordan, 1982 B78, B157, D37, D87 are presented. Different periods of the soybean seeds inoculation were used - on the sowing day (control) and in 7 days before sowing (experimental variants). The differences between control and experimental plants in the formation and functioning of the symbiotic apparatus and its functional activity, depending on the period between from seed inoculation to sowing were analysed. It was determined that the number of root nodules in the control plants was higher. The mass of nodules at the stage of 3 true leaves exceeded the control by 1.5–2.0 times in plants inoculated in 7 days before sowing, and the intensity of nitrogen fixation by 1.7–6.6 times. At the budding-beginning of flowering stage, the mass and intensity of N2 fixation by the nodules of control plants increased. As a result, the difference between the nitrogen fixing activity of control and experimental plants decreased significantly. Stimulating effect on aboveground mass of Bradyrhizobium japonicum strains with increased nitrogen fixing activity was noted. Optimal conditions for the formation and functioning of bean-rhizobial symbiosis were provided at the use of both of these terms of soybean inoculation. This reveals the possibility of effective application of early inoculation of soybean seeds with preparations based on nodule bacteria Bradyrhizobium japonicum active strains.

High biomass turnover rates of endosymbiotic nitrogen‐fixing cyanobacteria in the western Bering Sea

AbstractRecent studies have described active nitrogen fixation in high‐latitude waters, but the ecological controls on the occurrence or activity of nitrogen‐fixing organisms (diazotrophs) in such systems remain unknown. Turnover rates and top‐down controls are also general knowledge gaps for marine diazotrophs. We detected abundant UCYN‐A (endosymbiotic nitrogen‐fixing cyanobacteria) in the Gulf of Anadyr, western Bering Sea, which correlated with high dissolved iron to dissolved inorganic nitrogen ratios (Fe : DIN) due to riverine input. Growth and grazing mortality of UCYN‐A sublineages were almost balanced with higher biomass‐turnover rates compared to the whole phytoplankton community, indicating selective grazing of UCYN‐A in nitrogen‐depleted waters. Grazing rates on UCYN‐A1 (small cells) were higher than for UCYN‐A2/3/4 (large cells), consistent with the general size dependence of phytoplankton growth and grazing mortality. We found that Fe : DIN is a major determinant of UCYN‐A abundances in high‐latitude waters, where UCYN‐A could make substantial contributions to plankton food‐web cycling.

Characteristic of strains Priestia megaterium Ср-1 and Rhodococcus jostii СА-6 demonstrating increased salt resistance

The strains Priestia megaterium Ср-1 and Rhodococcus jostii CA-6 were shown to preserve phosphate-solubilising ability, nitrogen-fixing activity and synthesis of indole-3-acetic acid under osmotic stress conditions caused by sodium chloride in concentration range of 1197–2052 mmol/L, as well as to promote seed germination rate and development of small radish seedlings. Proline, betaine and sucrose were found to exert a beneficial effect on growth and ability of strains P. megaterium Ср-1 and Rh. jostii CA-6 to adapt to osmotic stress. Mass spectrometric analysis has revealed that intracellular synthesis of proline and betaine in both bacteria was directly proportional to sodium chloride concentration: rising NaCl level in the medium to 1197 mmol/L was accompanied by increase in proline level from 0.062 to 1.502 µg /mL (Rh. jostii CA-6) and from 0.089 to 2.105 µg /mL (P. megaterium Ср-1), in a similar manner betaine production grew up from 0.071 to 0.118 µg /mL (Rh. jostii СА-6) and from 0.055 to 0.219 µg /mL (P. megaterium Ср-1).

Effects of Dual Symbiotic Interactions Performed by the Exotic Tree Golden Wreath Wattle (Acacia cyanophylla Lindl.) on Soil Fertility in a Costal Sand Dune Ecosystem

The present study aims to evaluate the effects of the exotic shrub Acacia cyanophylla Lindl. on soil fertility by studying 1) its ability to modify the soil physicochemical composition, 2) its contribution to the soil mycorrhizal potential and its impact on the richness and diversity of the arbuscular mycorrhizal fungi (AMF) community in the rhizospheric soil (RS), and finally 3) its atmospheric nitrogen fixation potential. The physicochemical analysis of the RS has shown that soil invasion by A. cyanophylla has a beneficial effect on its fertility; this advantage is demonstrated by the increase of the organic matter and the nutrient contents (N, P, K, Na, Ca) in the RS. Furthermore, the roots of this shrub exhibited broad AMF colonization, which confirms its high mycotrophic aspect. Four differentiated morphotypes of mycorrhizal spores were isolated from the RS of A. cyanophylla by use of the wet sieving method. In addition, the most probable number method showed that A. cyanophylla was capable of dramatically increasing the mycorrhizal potential of the soil. Indeed, more than 1,213 infectious propagules per one hundred grams of soil were detected in the RS of A. cyanophylla. Moreover, A. cyanophylla roots showed a significant presence of nodules indicating an active atmospheric nitrogen fixation. Counting revealed the presence of at least 130 nodules in the root fragments contained in 1 kg of soil. In conclusion, the biological invasion of sand dunes by the exotic shrub A. cyanophylla exhibited beneficial effects on the soil’s chemical composition and functioning, the activity of rhizobacteria in fixing atmospheric nitrogen, and phosphate bioavailability under the action of the native AMF community.

Bisphenol A assisted Ti3C2Tx/CuZnInS Schottky heterojunction for highly efficient photocatalytic nitrogen fixation

Photocatalytic nitrogen fixation combined with degradation of organic pollutants is a promising technology to alleviate the growing energy and environmental crisis. In this work, Ti3C2Tx/CuZnInS (TiC/CZIS) Schottky heterojunction difunctional photocatalytic was rationally designed for efficient nitrogen fixation synergistic bisphenol A (BPA) degradation. The Ti3C2Tx ultra-thin nanosheets with richer surface-active groups and lower Fermi level greatly improved the carrier generation and separation ability of CZIS nanosphere. In addition, the coupling of TiC extended the absorption of CZIS to infrared region, which provided the possibility of efficient photocatalytic activity in cloudy and rainy days. As a result, an enhanced photocatalytic nitrogen fixation activity of 45.6 μmol/g/h was achieved. It should be noted that once appropriate amount of BPA was introduced to the photocatalytic system, a satisfied activity of 82.5 μmol/g/h was obtained, BPA can also be degraded by 58.5% within 180 min by TiC/CZIS. Through a series of experimental characterizations, the photocatalytic active substances and degradation pathway of BPA was investigated, and the possible photocatalytic mechanism was established. This work lays a foundation for the design of environmentally friendly photocatalysts and their applications in the fields of environmental purification and energy conversion.

Effectiveness of Rhizosphere Azotobacter Bacteria in Promoting Rice Growth and Yield in a Greenhouse

Azotobacter is a nitrogen-fixing bacteria. The growth and yield of rice (Oryza sativa L) in a greenhouse were studied to examine physiological characterization and efficacy of Azotobacter isolated from the rhizosphere and soil. The goal was to isolate Azotobacter that could be used as a biological fertilizer. There were 21 Azotobacter isolated, with 17 capable of nitrogen-fixing activity, 16 capable of protease activity, six capable of IAA activity, and 13 capable of phosphate dissolution. Each treatment was carried out three times in the experiment, which was completely randomized. At 105 days, the seedlings were harvested. The height of the plants, the number of leaves, the dry weight of the straw and grain, and the number of panicles and seeds were all evaluated. The results showed that rice yields were higher when 1 KZ was isolated from the turi plant (Sesbania grandiflora) and 15 KZ was isolated from the akasia plant (Acasia mangium).
 Keywords: Azotobacter, Rice Growth, Plant Growth Promoting Rhizobacteria

FUNCTIONING OF SOYBEAN-RHIZOBIA SYMBIOSIS AFTER VARIOUS METHODS APPLYING TRACE ELEMENTS COMPLEX

Objective. Investigate the effect of inoculation of soybean seeds with an active strain of nodule bacteria Bradyrhizobium japonicum T21-2 and treatment of seed or vegetative plants with a complex of trace elements Avatar-2 on the functioning of the symbiotic apparatus and grain productivity. Methods. Physiological, microbiological, gas chromatographic, vegetation experiment, statistical. Results. As a result of joint treatment of seeds with nodule bacteria and Avatar-2, inhibition of nodulation activity of nitrogen-fixing microorganisms in the stage of three true leaves was revealed in comparison with symbiotic systems formed as a result of standard inoculation of seed with rhizobia of Bradyrhizobium japonicum T21-2 strain. In the stage of budding / beginning of flowering and bean formation on the soybean roots of this variant, the number of nodules exceeded the corresponding figure in plants, bacterized without the use of trace elements by 16.6 % and 24.1 %, respectively. The combination of inoculation of seeds and feeding of plants during the vegetation with Avatar-2 did not have a significant effect on the activity of symbiotic systems in the stage of three true leaves and budding / beginning of flowering. However, in the stage of bean formation, a 38 % increase in nitrogen-fixing activity was detected compared to plants grown from seeds of rhizobia inoculated with Bradyrhizobium japonicum T21-2 strain (without the use of trace elements). Activation of soybean growth processes at all stages of plant development when exposed of seed bacterization and use of Avatar-2 by different methods was noted. Inoculation of seeds and using microfertilizers, both as separate elements of soybean cultivation technology and complex treatments in the conditions of vegetation experiment, resulted in a decrease in grain content of copper, zinc, iron and nickel. It was found that pre-sowing treatment of soybean seeds with a complex of chelated nutrients without bacterization caused an increase in grain weight per plant by 17.8 %, and when feeding non-inoculated growing plants with this fertilizer — by 27.5 % compared to the control. The combination of both factors — inoculation of seeds with a bacterial preparation and different using of trace element complex also had a positive effect on individual productivity of soybean plants, as evidenced by an increase of 14.4 % and 30.2 % compared to plants whose seeds were treated with rhizobia only. Conclusion. The combination of intensification factors in soybean cultivation technology through the use of different methods of complex microfertilizer and seed treatment with highly active strain of nodule bacteria has a significant impact on plant growth, content of individual trace elements in grain and creates a significant reserve of grain productivity of this crop.