Effect of Khelaphit biostimulator on photosynthetic activity and formation of winter rapeseed yield of different sowing periods in the Steppe zone

Abstract

Goal. To substantiate the influence of foliar treatment of plants with the growth stimulator of biological origin Khelafit on photosynthetic activity and the formation of winter rapeseed yield of different sowing periods in non-irrigated conditions of the Steppe zone. Methods. Field two-factor experiment was carried out during 2023–2025 in the conditions of the experimental field of Dobrobut LLC (vil. Mykhailivka, Mykolaiv district, Mykolaiv oblast) using the following methods: field (to monitor the growth and development of plants, and the formation of their yield); laboratory (to study the quantitative and qualitative properties of the soil); measuring and measuring-weight (to determine the yield and water regime of the soil); calculation-comparison (to determine the efficiency of the elements of cultivation technologies). The obtained experimental data were processed by analysis of variance. Results. It was determined that the yield of winter rapeseed varied depending on the terms of sowing and weather conditions of the year within a significant range — from 1.96 t/ha for the early sowing period in 2024 up to 5.00 t/ha for the optimal period in 2023. The best time for sowing was September 5, when the average yield increase compared to the early period was 0.63, and compared to the late period — by 0.78 t/ha. The use of the biostimulator Khelafit twice during the growing season contributed to an increase in yield, provided sowing in the early term by 0.34 t / ha, in the optimal — by 0.58, and in the late — by 0.82 t/ha. Conclusions. The use of the biostimulator Khelafit twice during the growing season of winter rapeseed made it possible to improve the indicators of its productivity in the case of late sowing to a level close to that observed under the condition of sowing in optimal terms, as well as to improve the yield indicator under the condition of early sowing by 0.33 t/ha.