Abstract

The experiment was conducted in the experimental field of the College of Agricultural Engineering Sciences / Salahaddin University-Erbil (SUE) (Erbil Governorate) during the fall season of 2023, aiming to evaluate the maize crop growth and controlling the accompanying weeds, using two herbicides and their combination under different planting distances. The experiment was implemented based on a randomized complete block design (RCBD) in a split-plot arrangement with three replicates. Plant densities (66,600, 57,100, and 50,000 plants.ha-1) occupied the main plots, and the weed control treatments (Nicosulfuron @ 48g.ha-1, Metribuzin @ 400 g.ha-1, Nicosulfuron @ 48g.ha-1 + Metribuzine @ 400 g.ha-1, weedy, and weed-free) occupied the sup-plots. The results showed that the plant density 66600 plants.ha-1 was superior, exhibiting the lowest average weed density 90 days sowing, the highest weed index, and the highest crop growth rate, reaching 9.80 plants.m-2, 26.13%, and 3.56 g.m-2.day, respectively, compared with the plant density of 50000 plants.ha-1, which gave the highest weed density of 13.04 plants m-2 and the lowest averages of the weed index and crop growth rate, attaining 36.45% and 3.23 plants.m-2.day-1, respectively, yet it was superior by recording the least number of days to reach tasseling and silking (51.80 and 57.33 days, respectively), compared with the plant density of 66600 plants.h-1, which took a longer number of days to reach tasseling and silking. The results also showed that the herbicide Nicosulfuron was superior in giving the best results, as it recorded the lowest average weed density after 90 days, the best weed index, the best crop growth rate, and the lowest number of days to 50% tasseling and silking (6.44 plants.m-2, 11.78%, and 3.71 g.m-2.days-1, 51.66 days, and 57.22 days, respectively) compared to the control treatment, which recorded the highest weed density (33.22 plants.m-2)