In order to investigate the abiotic stress (drought) tolerance of oat (Avena sativa L.) with silicon and sulphur foliar fertilisation treatments, and monitor the effect of the treatments on the physiology, production, stress tolerance, plant, and grain quality of winter oat varieties, a field experiment was conducted in the growing season of 2020–2021. As a continuation of our article, published in another Special Issue of Plants, in this publication we evaluate the effect of silicon and sulphur treatments on the quality of winter oats. The whole grain sulphur content was significantly different between varieties. The foliar fertiliser treatments caused greater differences in both the carbon and nitrogen, and sulphur contents in the green plant samples, compared to the differences measured in the grain. Foliar treatments had a significant effect on the sulphur content of both plant samples and grains. Significant differences in the Al, Ba, Ca, Cu, Fe, K, Mn, Mo, Na, Ni, P, Pb, Sr, and Zn contents of oat grains were measured, both between treatments and between varieties. Winter oat varieties did not respond equally to the foliar fertiliser treatments in terms of either macronutrient or micronutrient content. When P, K, Ca, Mg, and S were summarised, the highest values were in the control plots. Significant differences in protein content were identified between winter oat varieties in response to the treatments, but the varieties did not respond in the same way to different foliar fertiliser treatments. Based on our results, we recommend the use of foliar fertilisation in oats in drought-prone areas.

This study evaluated the effects of foliar silicon (Si) and sulfur (S) applications under contrasting climatic conditions on macro- and micronutrient accumulation in oat grain. The three-year field experiment (2022–2024) was conducted in Debrecen, Hungary, using a randomized complete block design (RCBD)with three replications. Grain samples were analyzed for macroelements (K, P, S, Mg, Ca) and micronutrients (Na, Si, Fe, Mn, Cu). Environmental conditions markedly influenced nutrient accumulation. Severe drought promoted the highest concentrations of K, S, and Mg, while mild drought significantly increased the accumulation of P, Ca, Si, Fe, and Cu contents. Moderate drought favored Na accumulation. Foliar S application under relatively favorable water supply significantly enhanced the concentration of all measured elements, with the strongest response observed for Cu (+47.4% compared with the control) and the weakest for Mg (8.5%). In contrast, Si application alone had only limited or negative effects, particularly under severe drought, where it reduced K (6.4%), S (2.4%), and Ca (13%) concentrations, despite increased Si accumulation in the grain. During drought stress, however, the combined Si + S treatment significantly increased the grain macro- and micronutrient concentrations. Among the tested genotypes, ‘Mv Pehely’ exhibited the highest macronutrient accumulation, while ‘GK Kormorán’ and ‘Mv Pehely’ showed superior micronutrient accumulation. ‘GK Pillangó’ and ‘Mv Szellő’ showed consistently lower nutrient contents. These results highlight the importance of genotype × environment × nutrient management strategies for improving nutrient composition in oat grain.

Dual-purpose usage is not a common technology for oats in Hungary, which is not surprising, as the area sown to our main crop is also very low. Yet the crop has a lot of untapped potential, not to mention its excellent nutritional parameters. In our experiment we investigated how much biomass can be expected after mowing winter oats at different phenological stages and whether we can expect a valuable grain yield after this process. Mowing was carried out at one-week intervals on a total of 4 occasions with 2 cutting heights. Plant height and NDVI values of the vegetation in the plots were measured during the experiment. After the harvest of the fully ripened grains, the yield and the thousand kernel weight (TKW) were determined. Our results show that with a lower cutting height (6 cm), a higher biomass yield can be achieved. The cutting height had no statistically verifiable effect on either NDVI or plant height. Droughty weather conditions during subsequent mowing significantly reduced the regeneration capacity of the plants, which was strongly reflected in the measured parameters. Furthermore, a higher grain yield was measured at a cutting height of 9 cm, which decreased gradually with the mowing time. Neither the cutting height nor the mowing time had any effect on the TKW.