The dissertation presents the results of studies on the influence of sowing methods on the formation of productivity of various soybean varieties in the conditions of the right-bank forest-steppe. Features of plant growth and development, formation and functioning of the photosynthetic and symbiotic apparatuses of soybean plants due to the influence of the factors under study were revealed. The assessment of individual plant productivity, productivity and quality of soybean seeds was carried out. An economic evaluation of soybean cultivation technologies based on sowing methods was carried out.
The research was conducted during 2022–2024 at the Institute of Feed and Agriculture of the Podillia NAAS, located in the Right-Bank Forest-Steppe. Hydrothermal conditions during the years of the research were characterized by high variability and differences from the average long-term indicators. Periods with an excessive amount of precipitation were replaced by soil and air droughts, which significantly affected the growth, development and productivity of various soybean varieties.
Each variety requires appropriate spatial arrangement of plants on the area, which is determined by the method of sowing. It should be noted that in the world and in Ukraine there is a clear tendency to narrow the row spacing in soybean cultivation. It was found that reducing the width of the rows from 45 to 15 cm led to an increase in soybean productivity by 4.2–12.6 %. The maximum yield was formed in the Titan variety (3.34 t/ha) and slightly less in the Kobuko variety (3.06 t/ha) when sowing with a row width of 15 cm, which is higher, respectively, by 7.4–11.9 % and 6.3–12.6 % compared to the variants of the experiment, where sowing was carried out with a row width of 30 cm and 45 cm. The highest yield in the Pallada variety (3.14 t/ha) was formed with a row width of 30 cm, which is 4.0–11.4 % higher than the other studied sowing methods.
High plasticity of soybean varieties to changes in the size of the feeding area has been established. That is, there is a certain range of densities within which a change in the feeding area contributes to an increase in the productivity of crop plants. The highest plant productivity indicators of the Titan variety were formed on the feeding area from 134 to 168 cm2, the Pallada variety - from 148 to 186 cm2 and Kobuko - from 167 to 202 cm2, which corresponds to the density from 734 to 585 thousand/ha, from 674 to 538 thousand/ha and from 598 to 495 thousand/ha and determines the highest yield of seeds per unit area. The subsequent increase or decrease in plant density led to a decrease in the level of individual productivity of soybean plants. The formation of crops with the optimal density of plants per unit area is one of the determining factors in the formation of the yield level of soybean seeds.
The maximum content of crude protein in soybean seeds of the Titan (40.0 %) and Kobuko (40.9 %) varieties was obtained on sowing options with a row spacing of 15 cm. In the Pallada variety, the maximum crude protein content (41.5 %) was noted for sowing with a row spacing of 30 cm. The highest fat content in soybean seeds of the Titan (20.8 %), Kobuko (20.4 %), and Pallada (20.1 %) varieties was obtained using similar variants, which is 0.7–1.8 % higher than other variants. When the row width decreased, the collection of protein and fat per unit area increased. With the row method of sowing with a row spacing of 15 cm, the Titan and Kobuko varieties received the largest increase in the collection of crude protein and fat, respectively, 0.17 t/ha, 0.19 t/ha and 0.13 t/ha, 0.12 t/ha against the wide-row method of sowing. The highest collection of protein and fat in the Pallada variety was for sowing with a row width of 30 cm, it increased by 0.19 t/ha and 0.08 t/ha compared to the wide-row method of sowing.
The economic evaluation of the technology of growing soybeans of the Titan and Kobuko varieties showed that the maximum conditional net profit, respectively, 24.49 thousand UAH/ha and 22.08 thousand UAH/ha, and the highest level of profitability, respectively, 129 % and 118 %, was provided by sowing soybeans in a row method with a row width of 15 cm, and the Pallada variety, respectively, 21.11 thousand UAH/ha and 113 % – sowing with a row width of 30 cm
