Investigating the efficiency of different herbicides in double-cropped cotton (Gossypium hirsutum L.) after canola (Brassica napus L.) in Golestan province

Nowadays, cotton as a second crop following rape (Brassica napus L.) in Golestan province is one of the appropriate methods to insert cotton in crop rotation. Hence, it seems necessary for weed control (volunteer rapes, in particular), and as a result to prevent qualitative and quantitative reduction of seed cotton yield. This study was conducted as a factorial in a randomized complete block design with two factors (cultivar and weed control method) and four replications. Cultivars were Armaghan, Golestan and Sepid. Weed control program consisted of two hand weeding and application of herbicides (Envoke, Convey, Treflan and Dioran). Based on the results, Golestan had the highest yield indicating its superiority as a second crop after canola to other cultivars. Among herbicides used, the highest control percent of volunteer rape was observed with Envoke treatment at 0.95 percent. Comparison among herbicides revealed that Envoke herbicide had significant difference for total lint yield (1289 kg/ha) with Convey (1155 kg/ha), Dioran (1159 kg/ha) and Treflan (1081 kg/ha). Therefore, planting Golestan cultivar and in addition application of Envoke, Dioran and Convey instead of Treflan as a herbicide in cotton double-cropping following rape is recommended.