کارایی علف‌کش تیفن‌سولفورون- متیل (هارمونی WG 75 درصد) درکنترل علف‌های‏هرز مزارع سویا (Glycine max (L.) merr.)

In order to evaluate the thifensulfuron-methyl (Harmony 75%WG) herbicide effectiveness on broad-leaved weeds in soybean fields, an experiment was conducted as Randomized Compelet Block Design (RCBD) with three replications in three locations (Golestan, Ardabil and West Azarbaijan provinces). The treatments were 1.Tereflan (triflutalin 2.5 l/ha as pre plant), 2,3,4 and 5.Harmony (thifensulfuron-methyl) (15, 30, 45 and 60 gr/ha) as pre-emergence, 6.Persuit (imazethapyr) 800 ml/ha as pre-emergence, 7.Bazagran (bentazon) 1.5 lit/ha as post-emergence at 4-6 leaved stage and 8.weed free treatment as a control. Portulaca oleracea L., Convolvulus arvensis L., Cyperus rotundus L., Echinochloa colonum (L.) Link, Sorghum halepense (L.) Pers. were the most important weeds in Golestan province. Amaranthus retroflexus L., Amaranthus blitoides S.Watson., Abutilon theophrasti Medicus, Xanthium strumarium L., were the most dominant weeds in Ardabil province. X. strumarium L., A. theophrasti Medicus, Hibiscus trionum L., Sinapis arvensis L. A. retroflexus L., Chenopodium album L. were the most important weeds in West Azarbaijan province. Based on the results of Golestan province experiment, after hand weeding treatment, the highest reduction percentage in weed density and dry weight was observed in 60, 45 and 30gr/ha of thifensulfuron- methyl. The highest seed yield was obtained by thifensulfuron-methyl 45 gr/ha at par with hand weeding and thifensulfuron-methyl 60 gr/ha treatments. The results of Ardabil province showed that all of the treatments increased yield 31-40 % than control treatment. The highest increase was observed in 45 and 60 gr/ha of thifensulfuron-methyl. The highest pod/ plant and seed/pod were obtained by 60 gr/ha of thifensulfuron-methyl. The most reduction percentage than control treatment was observed in 45 and 60 gr/ha of thifensulfuron-methyl in case of A. theophrasti, S. arvensis, A. retroflexus, and C. album weeds density in West Azarbaijan province. There was no significant difference between these two treatments in this case. However X. struamarium was controlled by bentazon herbicide better than the other treatments. The highest decrease in weed density and the most seed yield was observed 45 and 60 gr/ha of thifensulfuron-methyl. Visual assessment performed in the middle of the growing season showed the lack of herbicide-burning effects of thifensulfuron-methyl on soybean crop in Ardabil and West Azarbaijan, but in Golestan province, 5-10 % phytotoxicity caused by 60 gr/ha of thifensulfuron-methyl that elliminate after about 2 weeks. Based on the results of this experiment, application of 45 gr/ha of thifensulfuron-methyl can be recommended for broad leaved weed control in soybean crop.