IMPACT OF TERMS OF SOWING ON THE PRODUCTIVITY OF EARLY SOYBEAN VARIETIES IN IVANO-FRANKIVSK REGION

Abstract

The article highlights the materials of theoretical and experimental studies on the influence terms of sowing of early soybean varieties on their productivity in the conditions of Ivano-Frankivsk region. The research was conducted in a representative private farm in Ivano-Frankivsk region, characterized by soil and climatic conditions. Early varieties of domestic (Diona, Kobza) and foreign selection (Alaska, Arisa) were studied for different terms of sowing, which were determined by the temperature regime of the soil in the 0-10 cm layer. Early sowing was carried out at a soil temperature of 6±2°C, mid-season – at a soil temperature of 10±2°C, and late sowing – at a soil temperature of 14±2°C. It was found that the highest field emergence is observed for mid-season and late terms of sowing, respectively, and the survivability of soybean plants. The vegetative period of all soybean varieties in the conditions of the Carpathians region was extended on average from 10 to 15 days regardless of the terms of sowing. The formation of leaf apparatus varied in variants with varietal differences and depended on the terms of sowing. The maximum leaf area was formed in the crops of Diona variety for mid-season at 54,8 thousand m²/ha and late sowing at 55,9 thousand m²/ha. Shifting terms of sowing led to an increase in leaf area on average by 1,6-3,2 thousand m²/ha. Analyzing the yield, it was noted that seeds with the highest mass were formed during mid-season and late terms of sowing in all research variants. The variety Arisa demonstrated high yield indicators, where for mid-season sowing, the average yield over the years of the study was 3,41 t/ha, and for late sowing, it was 3,92 t/ha. The yield of the variety Kobza for mid-season and late sowing was 2,95 t/ha and 3,29 t/ha, respectively. The variety Alaska of Canadian selection had significantly lower yields. For early sowing, the yield was 1,69 t/ha, for mid-season – 1,88 t/ha, and for late sowing – 2,14 t/ha. We can note better adaptation to the soil and climatic conditions of the research area for the varieties Arisa, Kobza, and Diona. In all variety variants, shifting terms of sowing to later ones allowed for a yield increase ranging from 5 to 26%.