The dissertation provides a theoretical generalization and a new solution to an important scientific problem, which consists in the scientific substantiation and optimization of agricultural methods of sunflower cultivation in order to increase its productivity, taking into account the reaction of the hybrid to the main tillage systems, the use of mineral fertilizers and growth regulators in the Southern Steppe of Ukraine.
According to the results of the calculations, it was determined that the number of weeds in sunflower crops varied depending on the method of the main tillage and almost did not change depending on the fertilizer option and was the lowest under the classical system – 7.2–7.6 weeds/m2 (at the end of the growing season). . Under no-till and minimum tillage systems, their number increased to 9.1–9.3 and 15.0–16.1 pcs./m2. The air-dry mass of weeds changed under the influence of the main tillage system and the background of mineral nutrition. Under the classical system of basic tillage, it was equal to 22.1–33.1 g/m2. In sunflower crops under the no-till system of the main tillage, the air-dry mass of weeds increased by 11.5–13.5 g/m2 in relation to the classic one, and by 16.1–18.3 g/m2 under the minimum tillage system. In options with the use of mineral fertilizers, it increased by 5.7–11.0 g/m2, 4.3–10.7 g/m2, 4.9–12.4 g/m2, respectively.
It is calculated that the largest total water consumption by the crop (286.2 and 286.3 mm), but the lowest water consumption coefficient (832 m3/t) was noted for the classical system of the main tillage against the background of applying fertilizers in the dose of N60P60K60 with spraying of sunflower crops with a mixture of preparations Growth - concentrate + Gelatin oil (6–8 pairs of real leaves) and the first treatment: Gelatin phosphorus-potassium + Gelatin multimix + Gelatin mono boron (3–4 pairs of real leaves) and the second treatment: Gelatin mono boron (6–8 pairs of real leaves ).
When determining the impact of agricultural methods studied on indicators of productivity elements and yield, it was established that, depending on the option of using growth regulators, the largest indicators of basket diameter - 20.6-20.9 cm, number of seeds - 1327-1392 pcs., seed weight - 71 ,9–75.7 g from one basket and the mass of 1000 seeds – 53.9–54.3 g was obtained by applying fertilizers in the dose of N60Р60К60 under the classical system of basic tillage. A decrease in these indicators was noted for other power systems and backgrounds.
The highest yields of sunflower of the Ratnyk hybrid – 3.46 and 3.45 t/ha were obtained when growing under the classical system of main tillage, application of fertilizers in a dose of N60P60K60 for pre-sowing cultivation and two options of foliar feeding: Growth concentrate + Gelatin oil (6- 8 pairs of true leaves) and 1 treatment: Chelatin phosphorus-potassium + Gelatin multimix + Chelatin mono boron (3–4 pairs of true leaves), 2 treatment: Chelatin mono boron (6–8 pairs of true leaves).
It was determined that obtaining the maximum conditional net profit - UAH 57,059/ha was ensured by the cultivation of the Ratnyk hybrid sunflower under the classical system of the main tillage against the background of the application of mineral fertilizers in a dose of N40 with the use of growth regulators Rost-concentrate + Gelatin oil. The highest indicators of the level of profitability were obtained for the classical system of the main tillage in relation to other systems. The introduction of different doses of mineral fertilizers for all systems of the main tillage led to a decrease in the level of profitability. The largest increase in gross energy - 54672 MJ/ha was obtained under the classical system of basic tillage on the background of N40P60 and spraying of crops with a mixture of Rost-concentrate + Gelatin oil preparations.
According to the summarized results of the scientific work, in the farms of the Southern Steppe of Ukraine, in order to ensure the maximum realization of the genetic potential of sunflower and obtain a yield at the level of 3.45 t/ha, production recommendations are proposed:
- grow Ratnyk hybrid sunflower according to the classic system of the main tillage against the background of applying mineral fertilizers in a dose of N60P60K60 for pre-sowing cultivation with the treatment of crops in the phase of 6–8 pairs of true leaves with a mixture of Rost-concentrate and Gelatin oil preparations or the first treatment in the phase of 3–4 pairs real leaves: Phosphor-potassium gelatin + multimix gelatin + monoboron gelatin and the second treatment in phase 6–8 pairs of real leaves: monoboron gelatin
