Evaluation of biofertilizer effect on selective soybean herbicides efficiency to control of Xanthium spinosom and Datura stramonium

This experiment was conducted during 2009 growing season as split plot with randomized complete block (RCBD) design arrangement in a field of Faculty of Agriculture, Islamic Azad University, Karaj branch, Iran. Treating or not treating with biofeltilizer (Bradyrhizobium japonicum) was the main treatments. The sub-treatments were application of herbicides consisted of trifluralin, ethalfluralin, metribuzine, oxyflorfen, bentazon, aciflourfen+bentazon respectively at 1.2, 1.16, 0.35, 0.48, 1.2, 1.06 kg ha and weedy check. In this research, application of biofertilizer on efficiency of some herbicides was effective in decreasing weeds dry weight. The biomass of cocklebur (Xanthium spinosom) in treatments trifluralin, ethalfluralin, aciflurfen+bentazon or bentazon, was significantly less than weedy check, but oxyflorfen and metribuzin had no significant effect on the biomass of this weed. However, the herbicides, compared with weedy check, had no significant effect on the density of cocklebur. All herbicides, compared with weedy check, significantly reduced the density and biomass of jimsonweed (Datura stramonium). Regard less of statistic analysis, the mean biomass of jimsonweed in the treatment of aciflourfen+bentazon was less than the other treatments. Application of aciflourfen+bentazon, bentazon compared with weedy check resulted in significant grain weight of soybean. Compared with weedy check, all treatment except oxyflorfen, increased soybean 1000-grain weight. Although the soybean 1000-grain weight in the treatments aciflourfen+bentazon, bentazon and ethalfluralin was higher than other treatment, but these treatments were not significantly different from metribuzin and ethalfluralin.