EFFECT OF NITROGEN RATE ON YIELD AND YIELD COMPONENTS OF WHEAT IN WILD OAT INFESTED CONDITION

Research was performed to evaluate nitrogen effect on wild oat-wheat competition. A field study was conducted in 2011 at Ahwaz, Khuzestan, Iran. Two levels of wild oat (presence and absence) as main factor and three rates of nitrogen as sub factor were studied using a split plot design with four replicates. Maximum plant height increased with nitrogen supply in weed free and wild oat presence condition. Wheat maximum height in weed free condition was more than those grown in wild oat competition. Wild oat height was increased more than wheat all nitrogen rate. The maximum height of wild oat was 128.82 cm at 150 kgNha -1 rate. Addition of nitrogen increased wild oat biomass production. The effect of nitrogen rate on the relative biomass showed nitrogen application reduced relative wheat biomass while relative wild oat biomass was increased. These results indicate that wild oat competitive effects on wheat may increase with N supply.