Productivity of oat (Avena sativa L.) as affected by fertilization

Purpose. To identify varieties of oat (Avena sativa L.) by yield in the northern part of the Right Bank Forest Steppe of Ukraine, establish the efficiency of sulfur in the fertilization system and the specifics of the impact of nitrogen, phosphorus, potassium and sulfur application rates on crop productivity. Methods. Field studies were carried out at the Agronomic Research Station of the National University of Life and Environmental Sciences of Ukraine (Kyiv region) in 2021–2023 in typical low-humus chernozem soils according to the scheme of a two-factor experiment: factor A: variety [‘Neptun’ (control), ‘Lehin Nosivskyi’, ‘Svitanok’, ‘Zakat’, ‘Zubr’, ‘Albatros’, and ‘Aivori’]; factor B: fertilization system. According to the scheme of the experiment, the application of NPK) and N8P24K24S9 fertilizers was foreseen. Equalization of the nitrogen dose with the introduction of N8P24K24S9 was carried out by the introduction of ammonium nitrate. Ammonium nitrate was also used for nitrogen fertilization at the microstage BBCH 31–32. Results. The yield of oat varieties on average over three years yielded from 2.28 t/ha in the control option for the cultivation of the ‘Neptun’ variety to 5.54 t/ha for the cultivation of the ‘Aivori’ variety and the introduction of N120P120K120S45 + N30. A yield increase ranged from 0.32 to 2.83 t/ha, depending on fertilizers. Among the seven studied oat varieties, the most productive was the 'Aivori' variety, the yield of which, depending on the year and the fertilization system, varied from 2.38 t/ha in the control version in 2022 to 5.98 t/ha when applying N120P120K120S45 + N30 in 2023. The yield increase on average for the application of N120P120K120S45 + N30 was 2.73 t/ha compared to the control and 0.66 t/ha with the option where an equivalent rate of macronutrients was applied, but without sulfur. All oat varieties show a positive reaction to sulfur by increasing productivity, but its growth varies against the background of different rates of fertilizer application. Yield increases in varieties ‘Zakat’, ‘Zubr’ have a positive correlation dependence on the use of sulfur against the background of increasing rates of nitrogen, phosphorus and potassium application. Conclusions. Oat varieties are characterized by a specific reaction; however, all respond positively to increasing rates of fertilizers and the introduction of sulfur into the nutrition system, which increases the resistance of oats to lodging and the level of nitrogen use. The combined introduction of sulfur with macroelements provides a significant increase in yield, which is due to more efficient use of nitrogen by plants. Optimizing nitrogen-sulfur nutrition ensures increased efficiency of mineral fertilizers.