Response of rotational crops of wheat to soil residues of sulfonylurea herbicides

In order to study the response of rotational crops of wheat to soil residues of sulfonylurea, two field experiments were conducted in 2006-2007 growing season at 5 province of Iran, including Kermanshaj, Golestan, Fars, Khuzestan, and Tehran (Karaj andVaramin). The first experiment was arranged in a RCBD design with four replications in 2006. Treatments consisted of Chevaliar (Idosulfosulfuron + Mesosulfuron) at 0.4L/ha, Apyrus (Sulfosulfuron) at 28, 42, 56 and 70 g/ha, Megaton (Chlorsulfuron) at 20 g/ha, Bromicide + Topic ("Bromoxynil + MCPA"+ Clodinafop-propargyl) at 1.5+0.8 L/ha, Total (Sulfosulfuron + Mesosulfuron) at 45 g/ha, Atlantis (Idosulfuron + Mesosulfuron ) at 1.5 L/ha, weed infested and weed free. In this experiment corn was planted after wheat in 2007 growing season at all location. The second experiment was same as the first in 2006, but the crops that were planted after wheat were chickpea ( in Kermanshah), soybean (Golestan), sunflower (in Fars), mung bean (in Khuzestan) and canola (in Tehran). To evaluate the response of rotational crops, yield was measured. According to the result, in Khuzestan Total and Chevaliar reduced the yield of mung bean 28% and 14% respectively. Sulfonylurea residues could not reduced the yield of corn in Khuzestan, Fars, and Tehran, but residue of Chevaliar, Total and Atlantis in kermansha and Chevaliar in Golestan reduced the yield of corn 23%, 28%, 13% and 43% respectively. Chevaliar, Megaton and Total residues also reduced the yield of sunflower in Fars 30%, 15% and 50% respectively. In Kermansha, residues of Chevaliar, Megaton, Total and Atlantis reduced the yield of chickpea 96%, 89%, 20% and 30% respectively. The residues of Chevaliar and Megaton, in Karaj, reduced the yield of canola 13% and 20% respectively. In general, the residue of Apyrus did not have any adverse effect on the yield of crops and the risk of Atlantis residue was less. It also need pay more attention to the response of rotational crops of wheat to soil residues of sulfonylurea herbicides.