The influence of elements of soybean cultivation technology on the duration of vegetation and the dynamics of plant density

Abstract

The purpose of the research is to determine the effect of seed bacterization on soybean sowing and foliar fertilization with microfertilizers on the duration of vegetation and the dynamics of plant density in the agrocenosis. Methods. The research was conducted at the research field of the Vinnytsia National Agrarian University during 2023–2025. The soil of the experimental field is – gray forest medium loam. The technology of soybean cultivation, with the exception of the factors studied, was generally accepted for the right-bank forest-steppe. Predecessor ‒ winter wheat. Soybean variety Azimuth (medium-ripe). Sowing rate – 650 thousand/ha, row width 45 cm. Results. In the versions of the experiment, where only pre-sowing inoculation of soybean seeds was carried out, the vegetation of plants lasted 112–113 days, while in the control version (without drugs) the duration of the growing season was – 109 days. The end-of-bloom period – full ripeness of seeds (BBCH 69–89) during inoculation of soybean seeds and foliar fertilization with microfertilizers was characterized by an extended period of 2–5 days compared to the control (without fertilization) and 4-8 days compared to the absolute control of the experiment. At the control plots (without inoculation), the field germination rates of soybean seeds were lowest at 85.2–85.4 %. When carrying out the inoculation of soybean seeds with the preparation Bioinoculant-BTU-r (3.0 l/t), the field germination increased by 4.4–4.6 % when compared to the control areas (without treatment) and was at the level of 89.6–89.8 %, and the inoculation of soybean seeds Atuwa (2.0 l/t) + protector Premax (0.5 l/t) respectively at 6.0–6.3 % and was at the level of 91.2–91.5 %. The highest stand density rates of soybean plants were noted in areas where soybean seeds were treated with the Atuwa + Premax protector inoculant, at a consumption rate of (2.0+0.5 l/t) and were within 592.8–594.8 thousand/ha. On the variants with soybean seed inoculation with Bioinoculant- BTU-r, 3.0 l/t and foliar feeding with Yarilo Soya 2.0 l/ha and Helprost Soya, the 3.0 l/ha plant conservation ratio was at 91.8–92.8%. Conclusions. The sign of the duration of the soybean growing season is decisive for growing the crop in specific soil and climatic conditions. The longest growing season is – 122 days, noted on the variants of the experiment, where the bacterization of soybean seeds was carried out before sowing with the drug Atuva + protector Premax and foliar fertilization was carried out in the phase of the 3rd trifoliate leaf with Yarylo Soya microfertilizers, in the consumption rate of 2.0 l/ha and in the budding phase of Helprost Soya, in the rate of – 3.0 l/ha. The most favorable conditions for growth and development, and as a result, the greatest survival of soybean plants, were on the variants of the experiment with seed inoculation with the drug Atuva + protector Premax (2.0 + 0.5 l/t) and foliar fertiliza-tion with Yarylo Soya microfertilizers 2.0 l/ha (phase 2-3 trifoliate leaf) and Helprost Soya, 3.0 l/ha (budding phase). Under the conditions of these technological measures, the coefficient of preservation of soybean plants was 93.7%, while the absolute control of the experiment was at the level of 85.0%.