THE EFFECTIVENESS OF USING PRE-EMERGENCE HERBICIDES ON SUNFLOWER CROPS

Abstract

Purpose. To investigate the influence of pre-emer- gence herbicides on the degree of crop contamina- tion and sunflower seed yield. Methods. The research was conducted during 2022-2024 in the fields of the FG "Plakushchenko V.V.", located in the territory of the Odessa region, Velykymykhailivskyi district, in the village of Grebenyky. The method of laying the field experiment is split plots, main plots 1). (Control (without herbicide application), application of pre-emergence herbicide with the active substance (d.r.): 2). S-metolachlor 960 g/l, rate 1.6 l/ha, 3). d.r. Pendimethalin 330 g/l, rate 6.0 l/ha, d.r. 4). Dimethenamid-P 720 g/l, rate 1.2 l/ha), 5). Oxyfluorfen 240 g/l, rate 1.0 l/ha, 6). Hand weeding. Research results. The use of pre-emergence herbicides reduced the number of weeds in sunflower crops compared to the control, and the most effective was the pre-emergence herbicide with the active ingredient Dimethenamid-P 720 g/l. According to the research results, regarding the influence of pre-emer- gence herbicides on structural elements and biological yield, the lowest indicators: basket diameter ‒ 12.7 cm, number of seeds in a basket ‒ 469.5, weight of 1000 seeds ‒ 46.20 g, weight of seeds from one plant ‒ 21.70 g and bio- logical yield ‒ 1.07 t/ha were obtained in the control variant, while the highest, except for the weight of 1000 seeds, were obtained with manual weeding ‒ 18.5, 826.5, 54.53, 45.09 and 2.22 t/ha, respectively. The largest increase in indica- tors compared to control among pre-emergence herbicides was characterized by the variant using Dimethenamid-P (720 g/l): basket diameter ‒ 4.6 cm, number of seeds in a basket ‒ 213.9, weight of 1000 seeds ‒ 9.18 g, weight of seeds from one plant ‒ 16.13 g and biological yield ‒ 0.80 t/ha. Also, the lowest yield was obtained in the control variant: in 2022 0.57 t/ha, 2023 ‒ 1.06 t/ha, 2024 ‒ 1.19 t/ha and on average over three years ‒ 0.94 t/ha, and the maxi- mum with manual weeding ‒ 1.50, 2.04, 2.20 and 1.91 t/ha, respectively. The use of pre-emergence herbicides con- tributed to obtaining a higher yield compared to the con- trol variant, but less than with manual weeding. The largest increase in control among pre-emergence herbicides was characterized by the variant with the use of Dimethenamid-P (720 g/l): 2022 ‒ 0.74 t/ha, 2023 ‒ 0.63, 2024 ‒ 0.67 and on average over three years ‒ 0.68 t/ha. Conclusions. In our studies, the use of pre-emergence herbicides reduced the number of weeds, compared to the option without herbi- cides, but complete destruction of weeds was not observed in any of the study options. The highest yield of sunflower seeds 1.62 t/ha, oil content 50.10% and oil yield 0.81 t/ha was obtained in the option with the use of pre-emergence herbicide with a dosage of Dimethenamid-P 720 g/l, a rate of 1.2 l/ha.