IntroductionMaize (Zea mays L.) is a major crop in Iran and ranks third, behind wheat and rice. Grain yield in maize can be severely reduced by competition with weeds (Mosavi, 2001). A broad spectrum of grasses and broadleaved weeds infests maize fields. Amaranthus spp. (pigweed), Chenopodium album L. (common lambs quarters), Abutilon theophrastiMedik. (Velvetleaf), Cirsium arvense (L.) Scop. (Canada thistle), Convolvulus arvensis L. (field bindweed), Sorghum halepense (L.) Pers. (johnsongrass), Echinochloa crus-galli (L.) Beauv. (Barnyardgrass), Cyperus rotundus L. (purple nutsedge), Digitaria sanguinalis (L.) Scop. (Large crabgrass) and Setaria spp. (foxtail) are among the most common and problematic weeds in maize in Iran (Zandet al., 2009). Today, high-yielding agriculture heavily depends on herbicides, as they constitute a vital and integral component of weed management practices (Zand et al., 2008). Tank mixing two or more herbicides is a common practice that is increasingly used in most agronomic crops to control a wide spectrum of weeds, reduce production cost, and/or prevent the development of herbicide-resistant weeds (Zandet al., 2008). Herbicides may interact, before or after entering the plants, and the outcome of the interaction can be synergistic, additive, or antagonistic. It would be ideal to select herbicide combinations that have synergistic effects on weeds and/or antagonistic effects on crops. Additives, compounds that to facilitate the mixing application or influence herbicide add to herbicide formulation or tank sprayer, in other words additives can increase the effects of herbicides to reduce their consumption (Streibiget al., 1998). Foramsulfuron and nicosulfuron are among the newly released dual purpose sulfonylurea herbicides. The use of these herbicides offers the opportunity for a new mode of action for weed management in maize. These herbicides act through inhibition of acetolactate synthase, the first enzyme in the pathway in the biosynthesis of branched-chain amino acids, valine, leucine and isoleucine in chloroplasts. They first affect meristemic tissues where growth ceases soon after treatment. Chlorosis and the necrosis of these tissues soon follow, with dieback to the mature parts of the plant taking a further 3–4 week. These herbicides have been reported to be very effective on grasses, broadleaved weeds, and rhizomatous perennial temperate weeds in maize. Another priority of these herbicides over those currently used on maize is that they act at very low doses. This will reduce the environmental safety concerns lie back behind application of herbicides (Nurseet al., 2007; Prostko et al., 2006).