Comparison the efficacy of a few rice selective herbicide on control of weeds and crop yield in Mazandaran

This field experiment was conducted at Amol Rice Research Station in 2009 to evaluate the efficacy of rice selective herbicides in control common of barnyardgrass (Echinochloa crus–galli), sea clubrush (Scirpus maritimus) and common water-plantain (Alisma plantago-aquatica) and crop yield. The treatments were consisted of application of penoxsulam at 24, 30, 36 and 42 g ha-1, premixed of anilofos+ethoxysulfuron (Sunrise Plus) at 945 g ha-1, tank mix application of butachlor+cinosulfuron at 900+20 g ha-1, butachlor+bensulfuron-methyl at 100+45 g ha-1, twice hand weeding and weedy check. The herbicides were treated as droplet application seven days after rice transplanting. All treatments significantly reduced the number and dry weight of barnyard grass plants, but the effects of penoxulam at all rates of application, was more than that of butachlor+bensulfuron-methyl or anylofus+ethoxysulfuron. The lowest plant number of sea clubrush, similar to hand weeding, obtained from application of butachlor+bensulfuron which was significantly different from other herbicide treatments. Penoxulam at 24, 30, 36 or 42 g ha-1, in contrast to other treatments, showed no significant effect on dry weight of sea clubrush, compared with weedy check. All treatments completely (100%) controlled common water-plantain. The herbicide treatments, compared with weedy check, significantly increased rice foliage and root dry weight. The crop grain weight in weedy check was significantly lower than all treatments.