ESTIMATION OF THE SEEDING RATE AND SOWING TIME INFLUENCE ON THE REALISATION OF THE WINTER WHEAT POTENTIAL

Abstract

In the technological regulations for growing winter wheat, a correctly determined seed sowing rate contributes to the creation of normal conditions for plant growth and development, which significantly affects the crop yield level and its components. Thus, excessively thickened or thinned crops reduce the yield. The aim of the research was to evaluate and compare the effectiveness of different sowing rates and sowing dates on the productivity of winter wheat varieties in the conditions of the Western Forest-Steppe. Field experiments were carried out on the Luvic Greyzemic Phaeozems (WRB. 2015) during 2022–2023 at the stationary field experimental plots of the Rivne branch Ukrainian Institute of Plant Variety Examination, Rivne region (Ukraine). Laboratory analyses were performed using standard techniques. Sowing dates for winter wheat – first sowing on 10.10.2022, second sowing on 08.11.2022. The realisation of winter wheat potential depending on the sowing dates and, as a result, the shortening of the growing season of the studied varieties at different sowing rates differed significantly depending on the level of maturity of the variety. The level of overwintering of all studied winter wheat varieties, regardless of sowing dates, was estimated at 9 points. According to the data obtained, the coefficient of productive tillering of the studied varieties is inversely related to the seeding rate. The density of crops before harvesting, given the high level of overwintering of plants, is directly dependent on the seeding rate. The combination of the influence of different sowing rates and sowing dates did not equally affect the studied winter wheat varieties. According to the results of our research, it was found that for the medium-early variety Aurelius, medium-late varieties Tonnage and Gregor, sowing on October, 10 was more effective, while for the variants with the very early variety Aktivus, a higher yield was obtained when sowing was at later dates (November, 8) with different sowing rates.