Establishment of effective chemical means of weed control in amaranth crops

The widespread introduction of amaranth into agricultural production in Ukraine, particularly in the sufficiently moist conditions of the Western Forest-Steppe, is hampered by a number of technological difficulties, one of the key ones being weed infestation of crops. The purpose of the study was to identify effective herbicides for weed control in amaranth crops in the conditions of the Western Forest-Steppe of Ukraine. Field studies to determine effective herbicides – promethrin (500 g/ha); clomazone (480 g/ha); fenmedifam (60 g/ha) + desmedifam (47 g/ha) + ethofumesate (75 g/ha) + lenacil (27 g/ha); fenmedifam (320 g/ha); triflusulfuron (500 g/ha); clopyralid (750 g/ha) on amaranth crops were conducted during 2021-2023 on the experimental field of the Department of Plant Growing Technologies of Lviv National University of Natural Resources under conditions of sufficient moisture. Control – variant with biological methods of weed control. It was found that all the herbicides studied were effective in controlling weeds. The lowest number of weeds was found in the variant using the herbicide prometrin (500 g/ha) – 1.6 pcs/m2, and the lowest weed weight was found when using the herbicide clopyralid, 750-108 g/m2. All herbicides under study had a suppressive effect on amaranth plants, as evidenced by the parameters of the crop structure. In particular, the panicle length was the longest in the control (64 cm) and decreased to 49-56 cm in the variants with herbicide application, the height was 32-52 cm shorter, and the weight of 1,000 seeds decreased to 0.68-0.80 g. All the herbicides under study also caused a decrease in amaranth yield by 0.40-1.37 t/ha due to the stress effect on the plants. The highest amaranth yield was obtained in the variant with biological weed control methods – 3.21 t/ha. In the variants using herbicides, the highest yield (2.81 t/ha) was provided by the pre-emergence herbicide prometrin at an application rate of 2 l/ha