efficacy of paraquat herbicide for common bean (phaseolus vulgaris l.) weed management in stale seedbed practices

paraquat herbicide weed control efficacy in stale seedbed practices was evaluated by split plots arrangement according to a randomized complete block design with three replications in lorestan province during 2009 and 2010. the common bean seed rate (in three levels: 100, 150 and 200 kg.ha-1) and weed management in seven levels (1. trifluralin ppi; 2. paraquat pre; 3. bentazon+acifluorfen post; 4. trifluralin ppi+ bentazon+acifluorfen post; 5. paraquat pre +bentazon+acifluorfen post; 6. hand weeding; 7. weedy check) were allocated to main plots and sub plots, respectively. in the first year, among the herbicide treatments, the lowest weed density was belonged to the paraquat pre+bentazon+acifluorfen post, that reduced weed density by 68% in comparison to weedy check. trifluralin ppi+ bentazon+acifluorfen post, paraquat pre +bentazon+acifluorfen post, and bentazon+acifluorfen post alone were reduced weed biomass 83, 82 and 70%, respectively. based on the second year experimental results, all management treatments significantly reduced weed density compared to weedy check. treatments included trifluralin ppi, by average were reduced weed density 77% compared to weedy check. integrated application of paraquat pre+bentazon+acifluorfen post, also reduced weed density by 55%, and had not significant differences with superior treatment.