Evaluation of different herbicides on weed control, yield and yield components of soybean (Glycine max L.)

In order to investigate the effect of weed control with common herbicides on yield and components of soybean yield (Glycin max L.) in the second crop, two experiments were conducted as a randomized complete block design with three replications at the Agricultural and Natural Resources Research Center of Moghan during 2016-2017 and 2017-2018. The treatments consisted of Ethalfluralin, Imazethapyr, Trifluralin, Metribuzin, Bentazone and Alacolor herbicides with and without weed control. The results showed that the number of pods per plant, biological yield, grain yield and soybean protein percentage were statistically significant, but for chlorophyll index, 1000 seed weight and oil percent grain, the difference was not statistically significant. The highest number of pods per plant (333.92), biological yield (1221 g.plant-1) and grain yield (2792 kg.ha-1) were obtained from hand weeding. The results of the analysis of variance showed that the treatments had a significant difference in terms of the percentage of the effect of herbicide, density and total weed dry weight. The results showed that one month after spraying, the Trifluralin and Ethalfluralin herbicides had the highest effect on the weed control and two months after spraying, the rest of the treatments also showed their effect and all herbicide treatments were in one group. In this study, all weed control treatments significantly reduced the density and dry weight of weeds than without control, but their effect was less than hand weeding. The highest grain yield (1896 kg.ha-1) and the highest biological yield (784.9 kg.ha-1) were observed from Ethalfluralin herbicide