The biological and economic efficiency of the new herbicide Flex in post-emergence application to soybean crops of the variety Sphera was studied. The tests were carried out incompliance with the standard methods in the form of the plot experiment in 2017, 2018 on brown meadow podzolized soils in the south of the Far East. The preparation was tested in the consumption rates of 1.25 and 1.5 l/ha when the crop reached the development phase of two triple leaves as opposed to the standard herbicide Galaxy Top in the rate of 1.7 l/ha. It was found that Flex has a high herbicidal activity against all dicotyledonous annual and perennial species of weeds. Common ragweed (Ambrosia artemisiifolia L.) and Asian copperleaf (Acalypha australis L.) were highly sensitive to the preparation even in the minimum consumption rate. Especially strong toxic effect of Flex was produced on such weeds in the rosette phase as Asiatic dayflower (Commelina communis L.), lamb’s quarters (Chenopodium album L.), field milk thistle (Sonchus arvensis L.), creeping thistle (Cirsium setosum (Willd.) Bieb.) and common mugwort (Artemisia vulgaris L.). Consistent application of graminicide Fuzilade Forte in the rate of 1.5 l/ha after treatment of soybean crops with herbicide Flex contributed to an almost complete elimination of annual grass weeds. The high biological efficiency of the experimental preparation contributed to a significant increase in crop yield. In 2018, when it was applied in the minimum rate of 1.25 l/ha, the yield achieved was 0.94 t/ha, exceeding the control value by 3.3 times. The highest yield increase of soybean seeds (1.12 t/ha on average for 2 years) was obtained with the use of herbicide Flex in the maximum consumption rate of 1.5 l/ha. Application of herbicide Flex to soybean crops in the rates of 1.25 and 1.5 l/ha alongside with the preparation Trend 90 in the rate of 0.2 l/ha proved to be highly effective in eliminating annual and perennial dicotyledonous weeds (in early stages of development) from soybean crops.

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The work presents the results of testing tank mixtures of herbicides Proponit and Pledge applied in different doses to soybean crops during preemergence Treatment. The tests were carried out in Primorsky territory by standard methods in the form of the plot experiment in the trial field with brown meadow podzolized soils (by mechanical composition characterized as medium clay, content of humus 3.8%, labile phosphorus and exchange potassium in the soil 16 and 120 mg/kg respectively, PH 5.3). Hydrothermal conditions during the experiment were favorable for the implementation of the herbicidal potential of soil preparations. Trial tank mixtures showed high herbicidal activity against annual grass weeds (Echinochloa crusgalli, Setaria spp), annual dicotyledonous species (Ambrosia artemisiifolia, Acalypha australis, Abutilon theophrasti, Elsholtzia pseudocristata, Chenopodium album), Commelina communis and certain perennial dicotyledonous weeds. The use of mixtures of Proponit and Pledge in higher doses contributed to an increase in protective action and increase in the total herbicidal activity of preparations. The highest yield of soybean in the experiment, 2.41 t/ha, which exceeded the control value by 3.5 times, was achieved in the variant of the soil treatment with a mixture of herbicides in the maximum recommended rates (Proponit 3.0 l/ ha + Pledge 0.12 kg/ha). The economic efficiency of chemical weeding amounted to 39.0 thousand rubles/ha. Thus, in the conditions of soya crops contamination mainly by sensitive annual weed species and with optimal soil moisture, preemergence use of Proponit + Pledge tank mixtures was sufficient for reliable protection of soybean crops and eliminated the need for foliar herbicides.

An assessment of the biological activity of seven soil herbicides (based on seven active substances), permitted for use in soybeans, and their five tank mixtures, is given against the common barnyard grass. The study was carried out in the Primorsky Territory in 2018, 2019 in a greenhouse. The scheme of the experiment is presented: control (without herbicide treatment); Command, EC (active agent clomazone, 480 g/l) at a consumption rate of 1.0 l/ha; Zenkor Ultra, KS (active agent metribuzin, 600 g/l) – 1.0 l/ha; Gezagard, KS (active agent prometrine, 500 g/l) – 3.5 l/ha; Proponite, EC (active agent propisochlor, 720 g/l) – 3.0 l/ha; Dual Gold, EC (active agent S-metolachlor, 960 g/l) – 1.6 l/ha; Gardo Gold, KS (active agent S-metolachlor + terbutylazine, 312.5 + 187.5 g/l) – 4.5 l/ha; Pledge, SP (active agent flumioxazine, 500 g/kg) – 0.12 kg/ha; Gezagard + Dual Gold – 2.5 l/ha + 1.5 l/ha; Zenkor Ultra + Dual Gold – 0.5 l/ha + 1.5 l/ha; Command + Dual Gold – 0.7 l/ha + 1.5 l/ha; Proponite + Pledge – 2.0 l/ha + 0.10 kg/ha; Command + Pledge – 0.7 l/ha + 0.10 kg/ha. Barnyard grass was found to be quite sensitive to most of the herbicides and tank mixtures used in the experiments. Good control of barnyard grass was ensured by the use of herbicides Gezagard, Gardo Gold and Command. However, the extremely high biological efficiency (phytotoxicity) in relation to this species in conditions of a greenhouse and optimum herbicidal potential of soil herbicides, was demonstrated by preparations Dual Gold, Proponit and tank mixtures based on them. In this regard, Dual Gold and Proponit can primarily be recommended for soil application (separately and as part of tank mixtures) in soybean crops heavily contaminated with barnyard grass.

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