Sunflower hybrids productivity depending on the rates of mineral fertilizers in the south of Ukraine

Abstract Areas of sunflower cultivation in Ukraine, Europe, and the world have significantly increased over the past decade, along with an increase in crop yield, largely due to the development of new varieties and hybrids resistant to various abiotic stresses and extreme environmental conditions. The mineral nutrition background is also an important element of sunflower cultivation technology. The influence of mineral fertilizer rates on the productivity of new early-maturing and medium-early sunflower hybrids was the focus of research conducted during 2020–2021 on dark chestnut soils in the southern region of Ukraine. The results of the study showed that optimization of the mineral nutrition background contributed to increased plant height and leaf area. Both indicators were maximized for the cultivation of Alambra KS and Blyutuz hybrids with the application of fertilizers at the rate of N90P60. These experimental variants also ensured the formation of the maximum level of seed yield (3.05 t/ha for Alambra KS hybrid; 3.39 t/ha for Blyutuz hybrid) and the highest indicators of profitability per 1 kg of active substance of fertilizers (0.35 tons for Alambra KS hybrid; 0.45 tons for Blyutuz hybrid). The mineral nutrition background had little effect on the oil content in sunflower seeds. With an increase in the nitrogen fertilizer rate on the phosphorus background, the oil content in the seeds slightly decreased. However, the experimental variants differed in terms of conditional oil output per hectare of sunflower cultivation. Among early-maturing hybrids, the Alambra KS hybrid showed a higher value for this indicator, while among medium-early hybrids, it was the Blyutuz hybrid. The most effective rate of mineral fertilizers in terms of oil output was determined to be N90P60. Based on the results of the study on dark chestnut soils in the southern region of Ukraine, it is recommended to cultivate the Alambra KS hybrid among early-maturing sunflower hybrids and the Blyutuz hybrid among medium-early hybrids, with the application of mineral fertilizers at the rate of N90P60.