Efficiency assessment of weed control and soybean productivity depending on herbicide selection and timing of application

Abstract Herbicide protection affects the health and plants conditions of soybean and is influenced by the weather. Due to the increase in weed infestation in the initial period of plant growth, agrotechnical solutions are sought to enhance protection of plants against excessive weed infestation, taking into account the weather at sowing time. These solutions, however, are not always effective. The aim of the study was to compare the plant morphology, seed yield and weed infestation of soybean crop, cultivar ‘Merlin’, depending on the weed management and weather conditions. A two-factor field experiment was set up at the Bayer Crops Experimental Station in Chechło, Poland. The timing of application of herbicides (post-sowing and pre-emergence) and combinations of herbicides were compared. The study showed that application of herbicides immediately after sowing effectively regulates weed infestation of a soybean plantation and shows low phytotoxicity. In years with a high water deficit, herbicides should be applied immediately after sowing. The field experiment confirmed the positive effect of herbicide protection applied immediately after sowing on the habit of soybean plants and the crop yield. The choice of the broad-spectrum mixtures of herbicides Bandur 600 SC (aclonifen) and Sencor Liquid 600 SC (metribuzin) guarantees high efficacy with low or no phytotoxicity. To obtain high soybean yield, however, the application of the herbicide Artist (as a mixture of flufenacet and metribuzin) is recommended.