the effect of different weeds control and tillage systems on cotton’s weeds manangment in second planting after of winter wheat

to evaluate the effect of combined use of weeds control an different mechanical methods on weeds number and dry weight in cotton , a split plot experiment based on randomized complete block design was conducted at the region of boshruyeh in 2012. experimentals factors were tillage methods as main-plots with three levels, including conventional tillage, no-till system and minimum tillage; and different methods of weed control at 5 levels (trifloxysulfuron sodium at 10, 15 and 20 g ha-1, as well as no weeding and hand hoeing) as sub-plots with four replications. the results showed that there were significant differences between different methods of weeds control on weed number and weight of narrowleaf weeds and broadleaf weeds. the highest decreased of narrow leaf and broadleaf weed number was related to hand hoeing treatment with 99/02 and 72/75 %. the highest decreased narrow leaf and broadleaf weed numbers was shown in 20 mg ha-1 envok with adjuvant treatment with 54/98 and 53/51% after hand hoeing treatment. the highest decreased broadleaf and narrow leaf weeds weight was hand hoeing treatment 70% and 48/95%. the results showed that by adopting an appropriate concentration of herbicide envok with adjuant and preparation of seed bed can be to a great extent reduced weed farm.