Interaction Effects of Nitrogen Fertilizer and Nicosulfuron + Rimsulfuron herbicide on Weed Control in Grain Corn

In order to evaluate the effect of nitrogen fertilizer and nicosulfuron rimsulfuron herbicide on weed control in grain maizeSC704 hybrid, a field study was conducted as a strip experiment based on randomized complete block design with three replications during 2011 growing season in Research Field of Shiraz University located in Bajgah. The treatments included nitrogen fertilizer rates at four levels (0, 180, 270 and 360 kg ha-1), as main plots A and nicosulfuron rimsulfuron herbicide dosage at four levels (0, one-third, one-half and equal to the recommended dosage175 g ai ha-1) as secondary plot B. Results of interaction analysis showed that maximum weed dry weight was obtained in herbicide free plots with 360 kg ha-1 nitrogen fertilizer; which was significantly different from the recommended herbicide dosage in all fertilization levels. Minimum weeds dry weight was observed in recommended dosage plots with 270 kg ha-1 nitrogen which was not significantly different from 360 kg ha-1 nitrogen. There was no significant difference between 270 and 360 kg N ha-1 under the recommended herbicide dosage (175 g ai ha-1), in terms of maize yield and its components. Therefore, in order to achieve the maximum grain yield and best weed control, it seems that the recommended herbicide dosage and 270 kg N ha-1 would be the best option.