Agrobiological Assessment of Methods and Regimes of Combine Harvesting of Oil Flax in the Conditions of Southern Steppeof Ukraine

The article presents the results of two-year research on the dependence of a complex of quantitative and qualitative indicators of oil flax seed yield of Southern Night and Vodohray varieties, as well as seed sowing conditions on the methods and regimes of combine harvesting of the crop. The direct single-phase method of combine harvesting did not lag behind the control in terms of seed productivity per plant or M1000 indicator. Harvesting according to the two-phase scheme had a significant negative impact on the formation of these indicators: the M1000 indicator decreased by 0.5 g or 7.1% compared to the control, and the seed mass per plant decreased by 0.06 g or 15.4%. Pre-harvest desiccation in the single-phase method also negatively affected the formation of these indicators: when using Reglone Super, the M1000 indicator decreased by 0.7 g, Roundup by 1.0 g compared to the control; seed productivity per plant decreased by 0.07 and 0.1 g, respectively. The oil flax yield with direct single-phase harvesting was lower than the control by 0.03 t/ha or 2.1% (Southern Night variety) and by 0.04 t/ha or 3.0% (Vodohray variety). Additional desiccation of crops significantly reduced seed yield. When using Reglone Super desiccant, this reduction was 0.06–0.09 t/ha (4.5–6.4%), Roundup–0.10–0.13 t/ha (7.5–9.2%). The two-phase harvesting method yielded lower seed yield compared to the control by 0.10 t/ha (7.1%) when growing the Southern Night variety and by 0.08 t/ha (6.0%) when growing the Vodohray variety. The oil content of seeds of both flax varieties did not differ from the control with single-phase harvesting. Desiccation of crops during single-phase harvesting led to a significant decrease in crude fat content in seeds–by 0.7–0.9% (Southern Night variety) and 0.5–0.9% (Vodohray variety). Two-phase harvesting when growing the Southern Night variety contributed to a decrease in seed oil content by 0.5%, while it did not affect this quality indicator when growing the Vodohray variety. Laboratory germination similarity and energy reached maximum values in the control and in variants of direct singlephase harvesting without desiccation of crops–96.2 and 88.5–88.7%, respectively. Other studied methods and regimes of harvesting worsened the sowing conditions of oil flax seeds.