the effect of integrated weed management (chemical and mechanical) on density and dry weight of weed and introduction of new herbicide (envoke) in cotton (gossypium hirsutum) field in birjand region

in order to study the effects of mechanical and chemical methods of weed control and their interaction on cotton (cv. varamin) an experiment was conducted in agricultural research field, the university of birjand during 2008 growing season using a randomize complete block design with 12 treatments and 4 replications. treatments were: trefelan (trifluralin 48% ec) 960cc ai ha-1 (pre-plant), sonalan (ethalfluralin 33.3%) 999cc ai ha-1 (pre-plant), envoke 75 wg (trifloxysulfuron sodium) 11.25 gr ai ha-1 + adjuvant (citogit 2/1000) post- emergence at 2-8 leaves stage of cotton, once cultivator at 5-8 leaves stage of cotton, using twice cultivator at 2-4 and 4-8 leaves stage of cotton, trefelan + envoke, sonalan + envoke, envoke + cultivator, trefelan + cultivator and sonalan + cultivator. there were also two treatments whole season weed-free and weed-infested, as controls. result showed that the lowest weed density and dry weight was related to the treatment of using “envoke” along with ''citogit” and integrated treatments of envoke + sonalan and envoke + cultivator. integration of cultivator with sonalan, treflan and envoke was more effective than cultivator alone.