Influence of soil cultivation method and fertilization system on the yield of sunflower (Helianthus L.) when growing in conditions of Central Polissia of Ukraine

The paper presents three-year field and laboratory research on studying the sunflower hybrids of different cultivation technologies, types of ripeness groups with yield indices depending on using different fertilisers and different types of soil cultivation. The study was conducted when using new hybrids of domestic and foreign selection. The hybrids Grand Admiral and Pegas were selected according to their biological characteristics that are more typical for the zone of Polissia when using standard cultivation technology. It was noted that on sod-podzolic soils with a light mechanical composition, the use of disk tillage tools (BDVP-4.2) to a depth of 10–12 cm was not significantly inferior to the deep loosener (GR-4.5) to a depth of 40–45 cm, which was a shortfall grain yield from disking in both experiments was 0.08 t/ha (37.7%) and 0.21 t/ha (23%). The above-mentioned type of soil is naturally poor in terms of its physical and chemical composition, namely the content of humus (1.0–1.3%), availability of exchangeable potassium and mobile phosphorus (32–52 mg/kg), which creates the need to use scientific approach to the reproduction of soil fertility with the use of organic and mineral fertilizers. It has been proven that when using fertilizers N16P16K16 + N46 (nitroammophosca, 200 kg + urea fertilizer, 75 kg) an increase in sunflower seed yield equals 1.66–1.72 t/hа (281–322%), when using the fertilizers N10P26K26 + N46 (diammophos, 200 kg + urea fertilizer, 75 kg) the increase in yield equals — (287–328%) and when using P5K55 + N46 (phosphorus-potassium fertilizer, 20 kg + urea fertilizer, 75 kg) the increase in yield is the highest and equals 1.85–1.97 t/ha depending on the experiment variant. It is noted that the Pegasus sunflower hybrid was inferior to the Grand Admiral hybrid in all indicators of the experiment, from the form of mineral fertilizers to soil cultivation, and is: when applying N16P16K16 + N46 — 0.66 t/ha; N10P26K26 + N46 — 0.39 t/ha; P5K55 + N46 — 0.38 t/ha.