Comparison of different herbicides effectiveness in weed control and soybean (Glycin max L.) yield and yield components

An experiment was conducted to evaluate the effect of different common herbicides on soybean yield and yield components. Experiment was carried out using a randomized complete block design (RCBD) with three replications at the Agricultural and Natural Resources Research Center of Moghan, Ardebil, Iran during 2017-2018. Treatments were the application of ethalfluralin, imazethapyr, trifluralin, metribuzin, bentazone, and alacolor herbicides and with and without hand weeding control. The results of variance analysis showed that the treatments had significant differences in herbicide efficiency, weed density and total dry weight. One month after herbicides spraying, trifluralin and ethalfluralin had the highest effect on the weed control; however, two months after herbicides spraying, all other treatments also showed their control effects and all herbicides were located in same statistical group. In this study, all herbicides treatments significantly reduced the density and dry weight of weeds compared to control; however, their effect was less than hand weeding. The number of pods per plant, biological and grain yield and soybean protein content percentage were significantly affected by all treatments; however, the other traits including plant height, growth period, chlorophyll index, 1000-seed weight, and grain oil percentage were not significantly different. The highest number of pods per plant (333.92) and grain yield (2792 kg/ha) were obtained in hand weeding treatment. Among the herbicides treatments, the application of ethalfluralin had the highest seed yield (1896 kg.ha-1</sup>). Generally, based on the results of this study, application of 2 L.ha-1</sup> ethalfluralin could be recommended for effective weed control in soybean production systems.