ASSESSMENT OF THE IMPACT OF SEEDING RATES ON THE REALIZATION OF THE SOYBEAN DIFFERENT VARIETIES POTENTIAL

Abstract

Soybean seeding rate, as an agronomic technique, is one of the key factors in achieving high and stable crop yields. The optimal seeding rate ensures rational placement of crops on the feeding area, promotes more complete use of light, moisture, and nutrients, and reduces competition between crops in the field. The aim of the research was to estimate and compare the effectiveness of different seeding rates on the productivity of cultivated soybean varieties in the conditions of the Forest-Steppe zone of Ukraine. Field experiments were carried out on the Luvic Greyzemic Phaeozems (WRB.2015) during 2023–2024 at the stationary field experimental plots of the Rivne branch Ukrainian Institute of Plant Variety Examination, Rivne region (Ukraine). Individual productivity of soybean plants depending on the seeding rates was determined. The results of the research confirm that the optimal conditions for the formation of high indicators of individual productivity of soybean crops are provided at a seeding density of 450 thousand/ha. The Aurelina variety produced the highest weight of 1,000 seeds, the Abbaka variety produced the highest number of pods at low sowing density, while the Alicia variety showed better adaptability to thickening conditions. The Abbaka variety was characterized by a gradual increase in yield with an increase in seeding density. The lowest yield was obtained at a density of 450 thousand/ha – 3.05 t/ha, while the maximum yield – 3.77 t/ha – was formed at a density of 750 thousand/ha, which indicates a positive response of the variety to crop thickening. For the Aurelina variety, the highest yield was recorded at a seeding density of 650 thousand/ha – 3.61 t/ha. With a further increase in density to 750 thousand/ha, the yield decreased to 3.30 t/ha, which indicates the existence of an optimal planting density for this variety and the negative impact of excessive thickening. The Alicia variety provided the highest yield among the varieties studied. The maximum yield, namely 4.52 t/ha, was obtained at a seeding density of 650 thousand/ha. With an increase in density to 750 thousand/ha, a slight decrease in yield to 4.31 t/ha was noted, but this indicator remained higher compared to other options and varieties. Thus, the analysis of soybean yield taking into account LSD₀₅ confirms the significant impact of  seeding rates on crop productivity, which has a clearly expressed varietal character. Optimal seeding rates provide a reliable increase in yield and must take into account the biological characteristics of each variety.