Investigation of different weed control methods in hybrid rice.

This study have been planed to evaluate cono-weeder efficiency with other traditional weed control methods in Hybrid rice production. The Experiment design was a randomized complete block, split plat design with three replicates- Two Rice cultivars include Hybrid (IRH1) and khazar as main plots and eight weed control methods were considered as sub plots. Weeds randomly sampled from each plot using a 1×1 m2 quadrate, 14 and 28 days after transplanting and also 3 weeks before harvesting. The weeds were separated into grasses, sedges and broad leaves and dried hand and mechanical weeding time also measured in each plot after harvesting yield was recorded. From 20 m2 in each plot. Results showed the maximum weed dry weight in both cultivars belonged to control treatment while the minimum weed dry weight was pertained to (Herbicide + Hand weeding + Conoweeder).The maximum weeding time occurred in(Hand weeding + Conoweeder) for hybrid rice and the minimum weeding time in both cultivars belonged to (Herbicide + Hand weeding + Conoweeder).In both cultivars the minimum grain yield belonged to control treatment while the maximum grain yield in hybrid with 7110 kg/ha belonged to(hand weeding+conoweeder) and in khazar with 4867 kg/ha belonged to (Herbicide + Hand weeding + Conoweeder). This study showed that using cono-weeder reduce weeding time and labor cost .Concludely, between tested methods for better weed control in rice, the best methods was (Herbicide + Hand weeding+ Cono-weeder). The results in mazandaran showed that hybrid variety had better competition ability in weed growth and yield production than Neda variety. Among weed management the lowest yield was in control means it had maximum weed density and dry matter . Althouth the best treatment was (Herbicide +2 times hand weeding) (Herbicide + cono-weeder and hand weeding is recommended because that is easy to use and it reduces labor cost.