Dubynska O. Productivity of soybean varieties under seed inoculation with rhizobium and endophytic bacteria under irrigated conditions of the South of Ukraine

The research object is the processes of plant growth, development, yield formation and seed quality of soybean varieties depending on seed inoculation with rhizobium and endophytic bacteria under irrigation. The purpose was to substantiate scientifically and determine the specifics of plant growth and development and the formation of seed productivity of soybean varieties differing in a maturity type under seed inoculation with rhizobium and endophytic bacteria in irrigated conditions of the South of Ukraine. The following research methods were used in solving the scientific problems – general scientific methods and special methods: a field experiment, measuring and weighing, a laboratory method, a mathematical-statistical method, calculation and comparison. The results consist in improvement of the elements of the technology for growing soybean varieties of a new generation on dark-chestnut medium-loam soil in the Southern Steppe under irrigation. Complex pre-sowing inoculation of soybean seeds with highly effective strains of nitrogen-fixing and endophytic bacteria is a sufficiently effective measure since the use of it improves nitrogen and phosphorus nutrition of plants that contributes to a considerable increase in the crop seed yield and enhancement of its quality, reduction in applying mineral fertilizers, a rise in soil fertility and improvement of a phytosanitary condition of agro-phytocenosis on the whole. The novelty consists in the fact that the research paper is the first study investigating the features of production processes and the yield formation of soybean varieties differing in maturity types under complex endophytic-rhizobium inoculation of the crop seeds on dark-chestnut medium-loam soil of the Southern Steppe of Ukraine under irrigated conditions. The study determines the impact of soybean seed inoculation with rhizobium and endophytic bacteria, produced on the basis of nitrogen-fixing and phosphorus-mobilizing micro-organisms, on micro-biological composition of soil biocenosis by the periods between the crop stages. The study presents economic and energetic evaluation of the improved elements of the technology for growing soybean on irrigated lands of the Southern Steppe of Ukraine. The scientific value is the improvement of the energy-saving technology for growing soybean varieties differing in maturity types under conditions of the regional climate change with endophytic-rhizobium inoculation of the crop seeds. Correlation-regression analysis between the level of seed productivity of different soybean varieties differing in maturity types and the factors under study was performed. According to the results of economic and energetic analysis, the complex of technological measures for effective soybean seed production under conditions of the regional climate change on irrigated lands of the South of Ukraine was offered. The field of research is agriculture.