Nutritional conditions of plants during the growing season is one of the main factors aimed at realizing the genetic potential of sunflower hybrids for growing them in any soil and climatic conditions. Currently, it is important to study the genetic potential of domestic hybrids under different growing conditions in order to identify their competitiveness, which provides an increase in quality and yield of the crop. The use in the production of a significant range of complex microfertilizers on the background of the main fertilizer helps to increase the efficiency of plant use of nutrients of mineral fertilizers and soil, is one of the ways to increase crop yields and quality of agricultural products. Despite the relevance of sunflower as the main oil crop, the technology of its cultivation is not a perfect study, in addition, previous studies often contain conflicting indicators. An important place among the agronomic techniques aimed at increasing crop productivity belongs to the provision of optimal plant nutrition conditions during the growing season. The purpose of the research was to establish the influence of culture conditions and selection of high-yielding hybrids (NK Diamantis, SI Kupava, NK Neoma) for specific soil and climatic conditions through the formation of their productivity. The purpose of the research was to establish the influence of culture conditions and selection of high-yielding hybrids (NK Diamantis, SI Kupava, NK Neoma) for specific soil and climatic conditions through the formation of their productivity. The research was conducted during 2018–2019 on typical low-humus chernozems. The research program provided for the establishment of a three-factor field experiment, which studied hybrids (factor A) fertilizer options (factor B) and foliar fertilization of crops (factor B) in phase 4 and 8 sunflower leaves with Ecoline Bor, Nertus Bor, Bast Bor. The studied sunflower hybrids are NK Diamantis, SI Kupava, NK Neoma. The results of the research revealed significant changes in the diameter of the sunflower inflorescence under the influence of different nutritional conditions created by fertilizer options. The influence of hybrid characteristics also determined this indicator. Plants of the hybrid NK Diamantis formed baskets, the diameters of which varied from 17.6 to 21.2 cm, SI Kupava - from 18.8 to 22.1 cm, NK Neoma – from 17.2 to 21.6 cm. The maximum value was obtained on variant with the introduction of N36P56K108S28 + N23 + Ecoline Boron (phase 4 and 8 leaves) in plants of the hybrid SI Kupava, which corresponded to 22.1 cm. The weight of 1 000 achenes belonging to genetically determined traits of culture, in plants of the hybrid NK Diamantis, depending on the fertilizer variant varied from 59.3 to 62.3 g, SI Kupava from 69.8 to 74.0 g, NK Neoma from 68.8 to 72.6 g. The maximum value was provided by the variant with the use of N36P56K108S28 + N23 + Ecoline Boron (phase 4 and 8 leaves). Studies have shown that the most productive was the hybrid SI Kupava with the maximum yield on the variant with the use of N36P56K108S28 + N23 + Ecoline Boron (in phase 4 and 8 leaves of 1 l / ha) – 3.46 t per ha.

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.