Object – nutritious regime of chernozem opodzolic depending on the soybean fertilization, its growth and maturity, assimilation of nutrition elements, development of the yield and its quality. Purpose – to determine optimal and economically-grounded doses of nitrogenous fertilizers in combination with bacterial preparations in order to involve more biological nitrogen while growing soybean for grain on chernozem opodzolic heavy loam of the Right-Bank Forest Steppe Zone of Ukraine. Methods – field trials, laboratory-analytical, chemical and physical-chemical analyses of the soil and plant samples, methods of statistical processing of the information. Theoretical results – the effect of water supply of the soybean plants was identified and the coefficient of water consumption depending on the nitrogenous nutrition was calculated; dynamics peculiarities of the formation of biometric indicators of soybeans depending on the availability of movable nitrogen forms in the soil were studied; the change in the nutritious regime of the soil under the influence of mineral and biological nitrogen was defined; the dynamics of the content of the main nutrition elements in plant organs and their use per unit of the yield as well as the coefficient of the use from the fertilizers were found out; the effect of nutrition conditions on the yielding capacity, productivity elements and nitrogen-fixing activity of the plant and quality indices of soybean grain were identified; agronomical, economical and energy efficiency of the mineral fertilizer application both separately and in combination with bacterial preparations under soybeans was suggested. Practical results – allow to recommend the production sector to apply nitrogenous fertilizers at the rate of 60 kg a.s./ha under pre-sowing cultivation together with inoculation of seeds with highly efficient strain nitragin 71-Т, which enables to get the same yield as the one which is received when the rate of nitrogen is equal to 90 kg a.s./ha. Novelty – for the first time in theconditions of the Right-Bank Forest Steppe Zone of Ukraine on the chornozem opodzolic heavy loam the following was identified: extent of symbiotic nitrogen fixation of soybean plants, the increase of vegetative mass and the formation of the yield and its quality depending on the rates of fertilizer application and bacterial preparations. The ways of the optimization of the soybean nitrogen nutrition were further developed, which made it possible to add more biological nitrogen to its nutrition, to reduce a dose of mineral nitrogenous fertilizer, to decrease the cost of protein, to improve the ecology of the environment. From economical, agrochemical and energy point of view, efficient combination of mineral fertilizers and bacterial preparations was specified and explained. Degree of application – the main results of the research were introduced in 2005 at "Demetra", Matusiv, Shpola district, Cherkasy rgn.(the area of 108 hectares), in 2006 – farm enterprise “ЛНЗ-АГРО” Lebedyn, Shpola district, Cherkasy rgn. (the area of 80 hectares), and in 2007 - farm enterprise “Vidrodzhennia” Shpola, Cherkasy rgn. (the area of 220 hectares). The field is agrochemistry and agricultural sciences.
