Evaluation of the Effects of Different Herbicides on Weeds and Seed Yield of Broadbean, Vicia faba

In order to evaluate the effects of some herbicides on weed control and seed yield of broadbean an experiment was conducted in 2008 and 2009 at agricultural research center of Safi Abad of Dezful, I. R. Iran. The experiment was conducted in randomized complete block desigh with 13 treatments and three replications. Treatments included pre-plant application of trifluralin (EC 48%) at 1 kg ai/ha, pre-emergence and post-emergence application of imazethapyr (SL 10%) at 2 - 4 leaf stage of weeds at 0.04 and 0.075 kg ai/ha respectively, mixture of bentazon (EC 48%) + Halloxy fop R- methyl (EC 10.8%) at (0.75 + 0.08) kg ai/ha at 2 - 4 leaf stage of weeds, pre-emergence application of prometryn (WP 80%) at 0.8 kg ai/ha, pre-emergence application of pendimethalin (EC 33%) at 0.99 and 1.32 kg ai/ha, pre-plant application of metribuzin (WP 70%) at 0.35 and 0.52 kg ai/ha, pre-emergence application of metribuzin (WP 70%) at 0.35 and 0.52 kg ai/ha, weed free check and pre-emergence application of oxyfluorfen (EC 24%) at 0.36 kg ai/ha. Compared with the weedy check, on average, the sequence of the most to the least effective herbicide treatments on total weed control was recorded as oxyfluorfen> bentazon> metribuzin pre at 0.35 and 0.52 kg ai/ha > pendimethalin at 0.99 kg ai/ha > metribuzin PPI at 0.52 kg ai/ha. Compared with the weedy check, on average, the sequence of the most to the least effective herbicide treatments on yield increase was recorded as bentazon> pendimethalin at 1.32 kg ai/ha > oxyfluorfen> imazethapyr post > pendimethalin at 0.99 kg ai/ha, metribuzin pre at 0.35 kg ai/ha > metribuzin pre at 0.52 kg ai/ha. According to this experiment for weed control and seed yield increase of broadbean, application of each of the following herbicides at the above mentioned stage and rate are recommended: post-emergence application of imazethapyr at 0.075 kg ai/ha and mixture of bentazon + Halloxy fop R- methyl or pre-emergence application of pendimethalin, oxyfluorfen and metribuzin and also two handweedings throughout the growing season of broadbean.