The dissertation presents research results on the adaptability and productivity of oat varieties depending on the types and rates of fertilizers, and ecological factors of the environment. Oat varieties differ among themselves in terms of adaptability due to genetic characteristics, environmental and technological cultivation factors. Years differed in environmental parameters, which significantly influenced plants'
growth and development, and contributed to determining the adaptability of varieties. Analysis of thermal units accumulation shows that the difference in the total accumulation for the entire growing season was insignificant - the absolute indicators for the period March - July were: 2242.8 in 2021, 2209.8 in 2022, 2236.6 in 2023 r.; for the period of April - July they were: 2216.3; 2139.4; 2166.8 respectively. However, the decadal difference was significant and determined the difference in the duration of the macrostages and, accordingly, the number of formed generative organs.
The sum of effective temperatures was calculated at two biologically active temperatures – 5С and 10С, taking into account that oats are cold-resistant crops and actively grow and develop at temperatures close to or above +5С. The calculations show that the sums of the effective temperatures calculated for the two biological minimums differ significantly from each other.
Comparative analysis of temperature sums shows that the most objective indicator that characterizes the thermal regime for plants is the accumulation of the sum of thermal units, which are the largest compared to the sums of active and effective temperatures calculated for two biologically active minima.
The positive influence of sulfur in oats productivity formation and the importance of iodine for plant growth and development are substantiated, the optimal nutrition of oat plants contributes to the realization of the biological potential of varieties at a higher level. The dependence between the elements of domestic and foreign oat varieties productivity formation and the rates of mineral fertilizers was established, with a positive, very strong correlation, which varied depending on the variety in the range of r = 0.98–0.99.
The average yield of oat varieties for 2021-2023 ranged from 2.28 t/ha (control version, Neptune variety) to 5.54 t/ha (N120P120K120S45+N30, Ivory variety). Yield increases, depending on fertilizers, ranged
from 0.32 to 2.83 t/ha.
The variety-specific response to fertilizer rates, macroelements, and sulfurwas noticed. Among the seven oat varieties studied during 2021-2023, the Ivory variety was the most productive.
A positive reaction to the increasing rates of nutrients was also established for the Legin Nosivskyi, Zakat, Zubr, and Albatros varieties.
The Legin Nosivskyi is a new variety of domestic breeding - the year of registration is 2018. This variety has a high genetic potential and a fairly high level of realization.
All oat varieties had a positive reaction to sulfur application by increasing yield, but yield increases differed against the background of different nitrogen, phosphorus, and potassium rates.
The adaptability of varieties is identified through their plasticity and stability. Oat varieties respond positively to increasing rates of macronutrients and sulfur. The Neptune variety is low-plastic and unstable when applying almost all fertilizer rates, except combinations with sulfur.
Oat varieties respond positively to increasing rates of macronutrients, and the additional introduction of sulfur or iodine into the nutrition system helps to increase grain protein content, which is associated with more efficient use of nitrogen with a sufficient supply of sulfur, as well as the direct effect of mesoelements.
The fractional grain protein composition varies more depending on the fertilizing system than on the variety. An increase in fractions of reserve protein content was established with increasing fertilizer rates and with additional sulfur introduction.
The combined seed and vegetative plants treatment or only the treatment of vegetative plants by iodine-containing preparations contribute to the establishment of a greater number of generative organs and their reduction, which causes an increase in the grain mass from the plant and productivity in general.
The reliable effectiveness of iodine-containing preparations for protecting plants from disease has been established. Seed treatment by preparation with biologically active iodine protected plants against septoriosis at the level of the poison - 0.45 - 3.52%.
Analysis of the economic and energy efficiency of oat growing technologies was carried out taking into account the total costs of the technology, yield, and grain quality. Applying N30P30K30+N30+S11.25 the coefficient of energy efficiency varied slightly and was 2.96 - 3.88; N60P60K60 + N30+S22.5 – 2.68-3.46; N90P90K90 +N30+S33.75 – 2.51-3.14; N120P120K120+N30+S45.0 – 2.64-2.92.
