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Sunflower is a crop requiring intensive mineral nutrition, therefore, its cultivation demands reserves of nutrients in the soil, which can be replenished by applying mineral fertilizers. Purpose. Our purpose was to study the effects of fertilizers on the growth, development and yield of sunflower hybrids of different ripeness groups (bred at the Institute of Oil Crops) in the Left-Bank Forest-Steppe of Ukraine. Material and methods. The study was conducted at Poltava State Agricultural Research Station named after N.I. Vavilov in 2019–2020 The study object was processes of the growth and development of sunflower plants and formation of sunflower seeds depending on farming techniques. The study subject was sunflower hybrids Ahronomichnyi, Ahent and Serpanok. The following fertilizers were applied: 1) no fertilizers (control); 2) N32Р32К32; 3) N32Р32К32 + foliar fertilization of plants with urea (10 kg/ha) in the phase of 5–6 pairs of leaves; 4) N32Р32К32 + foliar fertilization of plants with microfertilizer Novalon Foliar (1 kg/ha) in the phase of 2–3 pairs of leaves; 5) N32P32K32 + foliar fertilization of plants with microfertilizer Novalon Foliar (1 kg/ha) in the phase of 5–6 pairs of leaves. Results and discussion. The results show that mineral macro- and microfertilizers contributed to more intensive growth and development of plants. Thus, the tallest plants, the largest leaves and calathidiums, and the highest 1000-seed weight were recorded hybrids Ahronomichnyi, Ahent and Serpanok with basic mineral fertilizers at a dose of N32Р32К32 + foliar fertilization with carbamide (10 kg/ha) or with microfertilizer Novalon Foliar (1 kg/ha). The maximum yields from hybrids Ahronomichnyi, Ahent and Serpanok were achieved with basic mineral fertilizers N32Р32К32 + foliar fertilization with microfertilizer Novalon Foliar (1 kg/ha) – 3.35 t/ha, 3.41 t/ha and 3.15 t/ha respectively. The gain to the control (no fertilizers) was 0.33 t/ha, 0.32 t/ha and 0.22 t/ha, respectively. Fertilization also affected the oil content in seeds. Mineral fertilizers N32Р32К32 decreased the oil content in the hybrid seeds by 1.1–1.7% compared to the ‘no fertilizers’ experiment. However, fertilization of plants during the growing period with urea or microfertilizer Novalon Foliar in combination with basic mineral fertilizers N32Р32К32 significantly increased the oil content in seeds. With the best yields, the highest output of oil from the hybrids was 1,406 kg/ha, 1,446 kg/ha and 1,356 kg/ha, respectively. Conclusions. Our results mainly confirm the results of other studies. Mineral fertilizers and microfertilizers promote more intensive growth and development of plants and increase the yields of sunflower seeds. However, there are some discrepancies in the oil content in seeds. Some researchers reported that mineral fertilization increased the oil content in seeds compared to the control (no fertilizers). We found that application of mineral fertilizers at a dose of N32P32K32 caused a decrease in the oil content in seeds, and only supplementary foliar fertilization with urea or microfertilizers increased this indicator
Totskyi et al. (Mon,) studied this question.