عنوان مقاله [English]
نویسندگان [English]چکیده [English]
A field experiment was conducted to assess the effect of lowered doses of herbicides on the control of perennial ryegrass (Lolium prenne L.) when growing in competition with wheat. The experimental design was a split plot factorial one with four replications. Main plots consisted of cropping system namely: Lolium pure stand vs. that grown with wheat. Sub plots consisted of two herbicides Clodinafop- propargyl and Mesosulfuron-Methyl (as two levels of the factor a) and 5 herbicide doses (0, %12.5, %25, %50 and 100 rate of recommended dose) in a factorial arrangement. Wheat yield was separately subjected to ANOVA in a randomized complete block design. Weed biomass in pure stand weed plots and in the presence of wheat exhibited significant differences. Clodinafop- propargyl did not totally control Loilium. Conversely, a full and a half full rate of Atlantis rendered a higher control of ryegrass and yielded significantly more wheat. By use of herbicide at more than 50% of full recommended dose, no increase occurred in wheat yield. As a whole spraying the field at 240 g/lit of Clodinafop- propargyl and 400 g/kg of Mesosulfuron-Methyl, field recommended rate, did not perfectly control the weed, indicating that it needs more investigation to optimize the herbicide dose for future recommendations.