The aim of the work was to determine the quantitative, qualitative composition and taxonomic structure of the eubacterial complex in the rhizosphere of sugar beet under different fertilizer systems. Microbiological methods were used to determine the content of microorganisms in the rhizosphere of sugar beet. Molecular methods were used to determine taxonomic structure as well as metagenome of the eubacterial complex of microorganisms. In the agrocenosis of sugar beet under different fertilizer systems the representatives of such families were prevailed as Alcaligenaceae, Pseudomonadaceae, Nitrososphaeraceae, Gaiellaceae, Micrococcaceae, Solirubrobacteraceae, Streptomycetaceae, Intrasporangiaceae, Solimonadaceae, Syntrophobacteraceae, Xanthomonadaceae, Enterobacteriaceae, Nocardioidaceae, Hyphomicrobiaceae, Comamonadaceae. It was found that under the biological system of fertilizers the species diversity of soil microbiota increased due to phyla: Alcaligenaceae, Gaiellaceae, Solirubrobacteraceae, Streptomycetaceae, Solimonadaceae, Syntrophobacteraceae, Xanthomonadaceae, Enterobacteriaceae, Nocardioidaceae, Hyphomicrobiaceae, Hyphomicrobiaceae. It was detected that the basis of the eubacterial complex of sugar beet included representatives of phyla Proteobacteria, Actinobacteria, Gemmatimonadetes, Chloroflexi, Acidobacteria, Firmicutes, Planctomycetes, Verrucomicrobia, Bacteroidetes, and the absolute dominants were Proteobacteria – 76.9%, Actinobacteria – 13,4 %.

The aim of the study was comparative evaluation of microbiological processes occurring in the soil and rhizosphere during the soybean cultivation in the conditions of short-term rotation with the use of different fertilizer systems. Methods.The content of ammoniating, amylolytic, pedotrophic, oligotrophic, asporousmicroorganisms, and micromycetes was determined. The soil and rhizosphere microbiological processes were characterized by mineralization – immobilization, oligotrophism, and pedotrophism coefficients. The use of ecological and biological fertilizer systems was accompanied by the increase of ammoniating microorganisms in the soybean budding phase. The use of exclusively mineral fertilizers of soybean has only significantly increased the development of microorganisms which use nitrogen of mineral compounds. The number of oligotrophic microorganisms was the highest, indicating that the stocks of readily available nutrients were depleted and that humification processes were intensified. For the ecological system of fertilizers, the coefficient of nitrogen mineralization-immobilization was 0.72-0.83, and for the biological system was the lowest 0.60-0.99. It confirms the equilibrium of the processes of mineralization and immobilization. The oligotrophic coefficients for the ecological and biological fertilizer systems at the stages of budding and browning of beans indicate the good availability of soil microbiota with easily digestible organic substances. The use of an ecological fertilizer system with a balanced combination of mineral and organic fertilizers and a biological fertilizer system with modern organic fertilizers and humates increases the activity of soil microbiota and improves the processes of organic compound transformation.

Soil microorganisms, root system of plants, organic residues and fertilizers contribute to the release of physiologically active substances and their accumulation in the root part of the soil. Accordingly, soil phytotoxicity affects the growth and development of agricultural plants. Therefore, the aim of the work was to evaluate the phytotoxic properties of the soil under different fertilization systems for winter wheat, soybeans, corn and sugar beets. Analysis of soil phytotoxicity was performed according to the method of A.M. Grodzinsky. At the beginning of the soybean growing season, the greatest phytotoxic activity was observed on the biological fertilizer system, which involved the use of corn residues (8-12 t/ha) + Biohumus "ECOCHUDO" 200 kg/ha, which is most likely caused by slow soil neutralization. microbiota of allelopathic secretions of cereals. It was established that the application of ecological and biological fertilization systems for winter wheat yielded minimal values of soil phytotoxicity and at the end of the growing season was 4.39-3.65 UCO, the lowest in the experiment. Under the ecological system of fertilizer (crop residues of wheat (8-10 t/ha) + N90P60K90) and especially biological (crop residues of wheat (8-10 t/ha) + Biohumus "ECOCHUDO" 1000 kg/ha) indicators of phytotoxic activity soil in the phase of 2-4 leaves in sugar beets were the highest, but during the subsequent growing season the values decreased by 34-47%. Due to the application of the ecological system of corn fertilization (crop residues of sugar beets (30-40 t/ha) + N15Р30К30) the phytotoxicity of the soil during the growing season decreased by 37.9%. At the same time, the maximum reduction occurred by 66.8% in the biological system of fertilizers (crop residues of sugar beets (30-40 t/ha) + Biohumus "ECOCHUDO" 750 kg/ha). Accordingly, the conditions of the soil environment under the biological system of agriculture were the most favorable for development: soybeans, wheat, sugar beets, corn.

The of the study was to determine the quantitative, qualitative composition and taxonomic structure of the eubacterial complex in the rhizosphere of winter wheat using different fertilizer systems.Methods.Microbiological methods were used to determine the content of winter microorganisms in the wheat rhizosphere, and molecular taxonomic structure and methane of the eubacterial complex of microorganisms were determined. Results.It was found that among large phyla on the variants of the biological system of winter wheat fertilizer the share of Proteobacteria increased to 80,3%, and the number of Actinobacteria decreased to 12.4% according to the control variant 76,3 and 17,5 %, also similar growth rates were marked on the variant of the ecological fertilizer system. The analysis of families shows that such families as Alcaligenaceae and Pseudomonadaceae were dominant in winter wheat crops with the use of different fertilizer variants. Under the industrial fertilizer system, the share of the family Alcaligenaceae was the highest, but with the application of biological and ecological systems it decreased, while the prevalence of the family Pseudomonadaceae on the contrary – increased. The use of organic fertilizers, compared with mineral, contributed to the formation of a variety of bacteria, so the greatest diversity of prokaryotes according to the Shannon index was in the biological fertilizer system – 4,82, and the least – in the industrial version of winter wheat fertilizer. Conclusions. It was found that in the variant of the biological fertilization system the increase of species diversity was due to the following phyla: Acidobacteria, Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria, Verrucomicrobia, and in the ecological fertilization system due to such philos as: Actinobacteria, Bacteroidetes, Firmicutes and Proteobac. In general, according to the experiment, the absolute dominants were representatives of bacterial philosProteobacteria – 79,1 %, Actinobacteria – 14,0%.

The research was carried out to establish the features of productivity formation of different by morphotype sunflower hybrids depending on plant density. Methods. Field and statistical. Multifactorial field experiment was based on the following scheme: factor A -'hybrid': 'Ukrainskyi F1', 'P63LL06', 'NK Brio', 'NK Ferti'; factor B -'plant density': 50, 55, 60, 65 thousand pieces/ha. Results. Field multifactorial experiment was established and conducted in the Left-Bank Forest-Steppe of Ukraine during 2016-2018 on light loam chernozem. The highest yield was formed by hybrid 'NK Brio' with a range of changes depending on year conditions and plant density from 3.20 to 4.20, with an average yield 3.63 t/ha for all variants. The hybrid 'NK Ferti' formed a fairly stable yield  with a range of changes from 2.70 to 3.79 t/ha and an average yield 3.27 t/ha. The yield range of hybrid 'P63LL06' was 2.583.52 t/ha, average for all studied factors  3.12. The yield of hybrid 'Ukrainskyi F1' varied from 2.16 to 3.11 t/ha, with an average 2.62 t/ha. The share of factors influence on sunflower yield formation is established. The biggest share in yields formation has the factor 'hybrid'  58 %, also plays an important role 'plants density' -14 %; interaction of factors "hybrid" and "plant density"  18 % and factor  "conditions of the year" -9 %. Conclusions. The lowest level of productivity was provided by cultivation of earlyripening hybrid 'Ukrainskyi F1', while cultivation of medium-ripe sunflower hybrid 'NK Brio' averaged 3.93 t/ha of seeds over the years of research with plant density 60 thousand pieces/ha. Productivity level of sunflower hybrids strongly depends on the density of sowings (correlation coefficients were obtained at the level of positive strong and very strong connection). Different precocious sunflower hybrids do not react equally to sowings density  it is necessary not only to select optimal areas for growing hybrids, but also to determine the optimal density of plants in the sowings. Due to agrocenosis formation with optimal plant density provides an increase in its productivity.