Rubtsov D. Optimization of elements of varietal technology as a factor in the formation of yield and sowing qualities of soybean seeds under irrigation in the south of Ukraine

Object of study – is the processes of growth, development, photosynthetic activity, the formation of seed productivity of the mid-season soybean variety Svyatogor. The aim is to determine the patterns of formation of the yield of conditioned seeds of medium-ripe soybean variety Svyatogor in the conditions of irrigation of the south of Ukraine depending on the optimization of plant density and doses of nitrogen fertilizer. Methods – historical retrospective - analysis of the selection process of culture in Ukraine; field - to determine the yield; calculated - to optimize the dose of mineral fertilizers; measuring and weighting - to establish the height of plants, leaf area and photosynthetic indicators, dry matter, structure of plant yield; laboratory - analysis of the chemical composition of seeds; calculation and comparative - to assess the economic efficiency of soybean growing technology; mathematical-statistical - for analysis of variance and statistical data processing to assess the reliability of the research results. Results – based on the results of research, recommendations have been developed for the accelerated propagation of the Svyatogor soybean variety and its effective use. It is established that with a shortage of conditioned seeds, the medium-ripe soybean variety Svyatogor and the need for its rapid reproduction must form a density of 300 thousand. Plants per hectare on the background of the application of 60 kg / ha (N60) of nitrogen fertilizer, allows to increase the reproduction rate to 49. To obtain a stable yield of Svyatogor at 4.5 t / ha or more, a net profit of more than 51 thousand. UAH / ha it is necessary to form the density of sowing at the rate of 600 thousand plants / ha against the background of nitrogen fertilizers at a dose of N30. The recommended technology was tested in DPDG "Askaniyskoe" of the Kherson region on the area of 30.0 hectares and DPDG "Kakhovskoe" of the Kherson region on the area of 20.0 hectares. The results of the implementation confirmed the high efficiency of the proposed elements of the technology, the additional income was 18.65 and 17.18 thousand. UAH / ha, respectively. Novelty - for the first time improved elements of technology for growing seeds of high-yielding medium-ripe soybean variety Svyatogor domestic selection, provided opportunities to increase yields and yield of conditioned seeds, its reproduction rate and increase the economic efficiency of seed production of the studied crop. The scientific value - lies in the theoretical substantiation of the peculiarities of selection and seed production of a new variety of soybean Svyatogor in the conditions of irrigation of the southern region of Ukraine. Sector – agriculture.