effect of different integrated weed management methods on weed characteristics and yield of sugar beet

in order to compare different weed management methods in sugar beet, an experiment was conducted at the agricultural research station, ferdowsi university of mashhad, iran, during 2006-2007 and 2007-2008. the experiment designed as a complete randomized block with three replications. the treatments including: metamitron + fenmedifam, metamitron + fenmedifam + rotation, metamitron + cultivation, metamitron + cultivation + rotation, disk + fenmedifam, disk + fenmedifam + rotation, disk + cultivation, disk + cultivation + rotation, covercrop + fenmedifam, covercrop + cultivation, hand-weeding and hand- weeding + fenmedifam. in the first year, apart from rotation treatments, the highest and lowest weed density were obtained in disk + cultivation (33 plant.m-2) and hand-weeding + fenmedifam (20.1 plant.m-2). in this year maximum amount of weed dry matter was seen in disk + fenmedifam with 89.2 g.m-2 and minimum dry matter of weed was showed in hand-weeding + fenmedifam with 22.2 g.m-2. in second year maximum and minimum weed density were showed in metamitron + fenmedifam with 142.6 plant.m-2 and hand-weeding with 21.5 plant.m-2, respectively. in this year highest and lowest dry matter of weed were obtained in metamitron + fenmedifam and hand-weeding + fenmedifam with 204 and 30.3 g.m-2, respectively. in first year maximum and minimum sugar beet yield were obtained with hand-weeding and cover crop + fenmedifam with 114 and 43.6 ton per hectare, respectively. in second year highest and lowest sugar beet yield were obtaned with hand-weeding and metamitron + fenmedifam with 94.4 and 28.3 ton per hectare, respectively. maximum sugar contains in first and second year were obtained in disk + cultivation (19.7) and disk + fenmedifam (18.3).