Efficiency of post-emergence (“insurance”) herbicides in soybean crops of the Northern Steppe of Ukraine

Abstract

Loss of soybean yields from weeds can reach 30–50%. Chemical methods of their control are of primary importance for obtaining the maximum grain yield. The critical period for weed control is stage from the first to third true leaf of the crop. The most active growth of unwanted vegetation in soybean crops is observed in the spring-summer period. And if during this period you can mainly suppress weeds, then in the future the crops will be relatively clean. In years when there is a sharp lack of moisture at the beginning of the growing season, a significant part of the plant seedlings appear at a later date, which creates additional problems for crop protection. In order to optimize weed protection measures, it is first necessary to know clearly the species composition of weeds in each specific agrocenosis. The development of highly effective systems of chemical protection of soybean crops against weeds largely depends on the application of highly effective herbicides. The maximum results in the control of weeds, in particular Сommon ragweed, at the time of renewal of spring vegetation, among the preparations used by as were provided by herbicides and their tank mixtures in variants with application of tank mixtures: Harmony: 8–10 g/ha + Command – 0,20–0,25 l/ha + Trend – 300 ml/ha. Here the technical efficiency was at the level of 70,0–72,0%. The increase of technical efficiency in variants with the application of tank mixtures of preparations was determined: Harmony – 8 g/ha + Command – 0,25 l/ha + Trend – 300 ml/ha; Harmony – 10 g/ha + Team – 0,20 l/ha + Trend – 300 ml/ha; Harmony – 10 g/ha + Team – 0,25 l/ha + Trend – 300 ml/ha and Harmony – 8 g/ha + Bazagran – 2,0 l/ha + Trend – 300 ml/ha. Spraying with herbicides and their tank mixtures in general made it possible to save from 0,81 to 1,01 t/ha of soybean grain, compared with the control without herbicides. Herbicide preparations differed slightly regarding the effect on the grain yield. It is necessary to distinguish only tank mixtures: Harmony – 10 g/ha + Commands – 0,20 l/ha + Trend –300 ml/ha; Harmony – 10 g/ha + Team – 0,25 l/ha + Trend – 300 ml/ha; Harmony – 8 g/ha + Bazagran – 2,0 l/ha + + Trend – 300 ml/ha, as well as Harmony – 12 g/ha. The indices of yields on these variants were maximum and amounted to 2,28; 2,31; 2,31 and 2,29 t/ha, which was more than the control by 43, 44, 44 and 43%, respectively.