Pinkovskyi H. Optimization of Elements of Sunflower Growing Technology in Right-Bank Steppe of Ukraine

The dissertation work is devoted to increasing of productivity of sunflower due to optimization of sowing time and density of standing of plants in the Right -Bank Steppe of Ukraine on ordinary heavy loam chernozem The optimal early terms of sowing of sunflower hybrids of middle-early maturity group taking into account change of weather conditions on the basis of analysis of data of temperature, water regime of soil and reaction of plants to change of standing density were established scientifically substantiated. The expediency and possibility of early sowing of sunflower have been proved. The optimal parameters of standing density of sunflower plants for hybrids Forward, LG 56.32, LG 54.85, LG 5582 are determined. The economic and energy efficiency of growing sunflower cultivation is substantiated. Due to economic indicators, the optimal time of sunflower sowing for hybrids LG 55.82 and LG 54.85 is warming soil at the depth of seed wrapping up to 5 – 6 °C, for hybrids Forward and LG 56.32 is warming soil at the depth of seed wrapping up to 9 – 10 °C, optimal density – 60 thousand/ha. In such conditions, the LG 55.82 hybrid formed the highest yield – 3.85 t/ha, LG 54.85 hybrid – 3.64 t/ha, Forward – 3.09 t/ha, LG 56.32 hybrid – 3.62 t/ha. Thus, sunflower productivity varied significantly under the influence of the morphobiological features of the hybrid – factor A (the proportion of impact was 47.5%), density of standing plants (factor C) – 5.4%, sowing time (factor B) – 3.4%. It is proved that the early sowing time leads to a higher level of profitability than the late ones. Among the hybrids, it is most economical to grow LG 55.82 when sowing with a soil temperature of 5 ‒ 6 °C. The net profit in this variant was 22043 UAH/ha, the level of profitability was 224.1%. The energy efficiency ratio was the highest during the first sowing period of LG 55.82 hybrid and was 4.44.