One of the main components of the formation of soybean productivity is a photosynthetic activity depending on the inoculation of seeds, mineral nutrition including foliar feeding. All of these factors contribute to optimal leaf surface and photosynthetic capacity of the both taken to the study varieties – Phaeton and Oksana. It is established that the cultivation of soy on dark chestnut soils in the conditions of the Southern steppe of Ukraine without irrigation the photosynthetic activity is enhanced in the cultivation by the use of fertilizers and seed treatment by nitrogen-fixing and phosphate mobilizing bacteria. Under the influence of these factors the level of soybean yield is significantly increased. However, leaf area, photosynthetic capacity and productivity of culture with enough close interdependence, and had been changed under the influence of climatic conditions of the year and primarily depend on the availability of plant moisture during the growing season. It is established that the most of soybean plants leaf surface area, photosynthetic capacity and yield were generated by introducing N30P30K30 and seed treatment of nitrogen-fixing and phosphate-mobilizing bacteria, or by the background of estimated dose of fertilizer. Maximum area of the soybean plants leaf surface in varieties Phaeton and Oksana is formed during the formation of beans on the background application of fertilizers and seed inoculation before sowing. By entering N60P30K30 and N30P30K30with feeding by Kristal on during plants budding and calculated doses of fertilizers (including level of productivity and moving NPK content in the soil) assimilation surface of soybean plants was nearby the same and was much higher than not fertilized control. With the same dependence as the leaf surface of plants photosynthetic potential of both sowing soybean varieties changed too. Close correlation between the formation of soy photosynthetic apparatus and its productivity is determined.
soy, soybean, fertilizers, inoculation of seeds, leaf surface area, photosynthetic capacity, yield.