Nitsenko M. The effectiveness of the use of biological agents and narrow spaces between rows in growing sunflower in the Northern Steppe of Ukraine

Object of study - processes of formation of seed yield of sunflower hybrids featuring different ripening periods based on the use of nitrogen-gathering and phosphate-solubilizing bacterial preparations combined with the growth regulator as well as methods of sowing and planting density under the conditions of the Northern Steppe of Ukraine. Purpose of study - to determine the features of growth, development and productivity of new hybrids of sunflower plants, develop environmentally friendly methods of their cultivation through the use of bacterial fertilizers and growth regulators and optimize the form and area of plant nutrition. Methods - field, laboratory, measuring and weighing, computation-comparative, mathematical-statistical. Results: an advanced environmentally friendly technology of sunflower growing which includes the use of such microbiological preparations as Diazofit, CL-9 and Phosphoenterin in combination with growth regulator Vympel which makes it possible to increase the yield capacity of sunflower hybrids by 0,14-0,71 t/ha. With the application of narrow row spacing of 35 cm such sunflower growing technology ensures an increase in crop yield up to 0,28 t/ha. These technological developments have been tested and implemented on a number of farms in the Dnipropetrovsk region and provided the net profit of 850-988 hrn./ha and an increase in the sunflower yield by 0,35-0,50 t/ha. Novelty – for the first time ever, under the conditions of the Northern Steppe of Ukraine, the features of growth, development and yield formation of new sunflower hybrids of different morphological types depending on the application of microbiological preparations both separately and in combination with growth regulator Vympel have been determined. The influence of biological preparations on the plant moisture status, drought resistance and phytosanitary condition of sunflower crops has been determined. The expediency of narrowing space between rows up to 35 cm when growing sunflower crops and overcrowding of crops up to 75 thousand plants per 1 hectare has been proved with an increase in the seed yield by 10-11%. Sector – agriculture.