ارزیابی کارآیی زمان و میزان مصرف علفکش متری بوزین در کنترل علف های هرز ذرت دانه ای

This experiment was conducted in 2007 and 2008 in order to evaluate the efficacy of metribuzin herbicide on weeds and yield of corn, at agricultural research center of Safi Abad of Dezful,. The experimental design was randomized complete block with 13 treatments and three replications. Treatments included preplant, preemergence and postemergence application of metribuzin at 3-4 leaf stage of corn and weeds each at 0.35 and 0.52 kg ai/ha, preplant, pre-emergence and postemergence application of metribuzin + atrazine at 3-4 leaf stage of corn and weeds at (0.175 + 0.6) kg ai/ha, nicosulfuron at 0.08 kg ai /ha at 3-6 leaf stage of corn, preemergence application of atrazine + alachlor at (1.2 + 2) kg ai /ha, weedy and weed free checks. Compared to the weedy check, total number of weeds were reduced by preplant, preemergence and postemergence application of metribuzin by 37, 33 and 72%, respectively, by preplant, preemergence and postemergence application of metribuzin + atrazine by 31, 20 and 75%, respectively, by nicosulfuron and mixture of atrazine + alachlor by 63 abnd 67%, respectively. In 2007, there was not significant difference among herbicide treatments for corn grain yield, but in 2008, Compared to the weedy check, corn grain yield was increased by preplant, preemergence and postemergence application of metribuzin by 110, 77 and 167%, respectively, by preplant, preemergence and postemergence application of metribuzin + atrazine by 111, 164 and 199%, respectively, by nicosulfuron and mixture of atrazine + alachlor by 10 and 17%, respectively, and weed free check by 53%. According to this experiment for weed control and yield increase of corn preemergence or postemergence application of metribuzin, preplant, preemergence or postemergence application of metribuzin + atrazine, nicosulfuron or mixture of atrazine + alachlor each at the abovementioned rates are recommended.