The influence of sowing time on the yield of different varieties of winter crops in the conditions of Black Sea Steppe of Ukraine

Abstract

Goal. To identify elements of climatically oriented biologized technology for growing promising varieties of winter crops for the arid conditions of the Southern Black Sea Steppe of Ukraine. Methods. The experiment used: the field method (to monitor plant development and yield); the laboratory method (to analyze grain); the mathematical method (to process the data and determine the reliability of the results). Results. The study was conducted in 2023–2025 at the experimental field of the Odesa State Agricultural Experimental Station of ICSA of NAAS. The soil of the experimental field was the southern non-washed heavy-clay chornozem. The scientific basis of the influence of the terms of sowing on the formation of the yield of promising varieties of winter wheat and winter barley was determined. The reaction of new varieties of winter wheat and winter barley to different periods of sowing was fixed. It was determined that the terms of sowing significantly affected the yield of winter crops, which were studied in the experiment. The highest yields of winter wheat over the years of research were obtained for sowing on October 5 in most varieties of winter wheat: a) for sowing on October 5, the yield was on average at the level of 6.06 t/ha, the excess was 8.6% compared with sowing on September 25, 2.7% — compared with sowing on October 15; b) for sowing on October 15, the yield was 5.90 t/ha, which was 5.7% more compared to sowing on September 25 and 17.5% compared to sowing on October 25. The highest crop was formed during sowing on October 5 in the following varieties of winter wheat: Hromada — 6.52 tons/ha, Vahoma — 6.48 tons/ha, and Katrusia Odeska — 6.38 tons/ha. It was found that the highest yields of winter barley over the years of research were obtained for sowing on October 5 and 15 in most of the studied varieties: a) for sowing on October 5, the average yield of 6 winter barley varieties was 5.95 t/ha, which was 7.4% higher compared to sowing on September 25; b) for sowing on October 15, the average yield was 5.96 t/ha, the excess reached 7.5% compared to sowing on September 25. The highest yield on average was formed by the following varieties of winter barley: in the case of sowing on October 5 — Evolutsiia (6.53 t/ha), Deviatyi val (6.18 t/ha); for sowing on October 15 — Valkiriia (6.25 t/ha), Rusyn (6.12 t/ha), Deviatyi val (6.09 t/ha). Conclusions. Now, for the zone of the Southern Black Sea Steppe, the optimal period of winter wheat sowing can be recommended as October 5, which ensures the formation of the highest crop yield. As for winter barley, the terms of sowing need further clarification. On average, over the years of research, most of the studied varieties formed the highest yield for sowing on October 5 and 15. At the same time, the reaction of varieties of different types of development (typically winter and varietal types) to the terms of sowing was similar, which indicated the possibility of their comparative assessment within the framework of the studies. In abnormally dry conditions in autumn 2023, the maximum harvest of winter barley grain was obtained for a later sowing period — October 25 — which confirmed the significant influence of weather conditions of the autumn period on the formation of crop productivity. Compared to similar studies conducted 8–10 years ago, the optimal terms of sowing winter crops in the zone of the Southern Black Sea Steppe tend to shift to a later period (5–10 days), which is probably associated with changes in climatic conditions. In view of this, it is advisable to continue research with an expansion of the range of sowing periods, in particular towards later ones.