Mostypan O. Formation of soybean productivity depending on agrotechnological measures of cultivation in the conditions of the Right-Bank Forest-Steppe of Ukraine

The dissertation presents a theoretical generalization and practical solution of the scientific problem of the peculiarities of the processes of growth, development, yield formation and quality indicators of soybean varieties under the influence of herbicidal and fungicidal protection, taking into account the hydrothermal conditions of the Right-Bank Forest-Steppe of Ukraine. The obtained results and developed recommendations are based on an integrated approach to increasing the productivity of soybean varieties by optimizing the elements of cultivation technology. The relevance of the topic, the connection of the research with scientific programmers, plans, themes, goals and objectives, which was achieved by demonstrating the effectiveness of the use of combined herbicidal and fungicidal protection in modern technologies for the cultivation of early ripening and early maturing soybean varieties in the conditions of the Right-Bank Forest-Steppe of Ukraine, are emphasized. The scientific novelty of the study is the solution of an important scientific task of improvement of the elements of the technology of soybean cultivation using herbicidal and fungicidal protection of early maturing and early ripening varieties in the conditions of the Right-Bank Forest-Steppe of Ukraine. This study differs from previously known results in that it applies a comprehensive approach to solving this problem. The influence of herbicides and fungicides on plant growth and development, seed germination in the field, photosynthetic activity and individual productivity of soybean plants, which ultimately determines yield and grain quality, has been demonstrated. The effectiveness of soybean cultivation with pre-sowing seed treatment with fungicides and their subsequent application to vegetative plants has been demonstrated and experimentally proven. The expediency of using post-emergence herbicides to control the number of weeds in soybean fields and improve their phytosanitary condition was determined. The principles of productivity management of the process of formation of yield and grain quality of soybean varieties of different maturity groups, depending on climatic conditions, herbicidal and fungicidal protection, were further developed. The practical significance of the results obtained is the development of scientifically based recommendations for improving the elements of soybean cultivation technology, including the selection of early maturing and early ripening varieties and the combined use of herbicides and fungicides, which ensures a high level of yield and grain quality. It was found that the maximum duration of the growing season was 106-109 days for the soybean variety Aurelina and 97–99 and 99–101 days for the varieties EС Commandоr and EС Navigator. The longest vegetation period of the varieties studied was in 2021 – 109–112, 100–102 and 102–104 days. In the varieties treated with pre- and post-emergence herbicides, the duration of the vegetation period was 2–3 days shorter than in the control. It was proved that the highest values of plant height were obtained in the Aurelina variety with post-emergence application of herbicides Corum (2 l/ha) + surfactant Metolat (1 l/ha) + Achiba (2 l/ha) – 90.2 cm. For the varieties EС Commandоr and EС Navigator, it was 73.1 and 73.5 cm in this trial variant. Among the soybean varieties studied, the tallest was Aurelina – 80.2–90.2 cm. It was found that the increase in leaf area of soybean plants occurred from the budding phase (BBCH 53) to the formation of beans (BBCH 74–78). In the varieties Aurelina, EС Commandоr and EС Navigator, the maximum leaf area of soybean plants was 42.9, 41.5 and 43.7 thousand m2/ha in the variants with post-emergence application of Corum (2 l/ha) + surfactant Metolat (1 l/ha) + Achiba (2 l/ha). Under the influence of fungicidal protection, the leaf area of varieties Amadea and Aurelina increased by 1.1–6.6 % in the flowering phase and by 5.4–11.9 % in the bean-forming phase compared to the control. It was found that the highest index of photosynthetic potential of crops was recorded in the soybean variety EС Navigator on the variant of application of post-emergence herbicides Corum (2 l/ha) + surfactant Metholat (1 l/ha) + Achiba (2 l/ha) – 1.260 million m2/day × ha. For the varieties Aurelina and EС Commandоr, they were 1.240 and 1.220 million m2/day × ha, respectively. The best conditions for the formation of photosynthetic potential of plants in varieties Amadea and Aurelina were in the variant of using fungicides Standak Top (2 l/t) and Abacus (2 l/ha) – 2.236 and 2.179 million m2/days × ha. Similar values of this indicator were obtained in the variants Selest Top (1 l/t) + Abacus (2 l/ha) and Vaibrans (1 l/t) + Abacus (2 l/ha) – 2.227 and 2.208 and 2.158 and 2.146 million m2/days × ha.