Document Type : Primary Research paper
Department of Field Crop, College of Agriculture, Tikrit University, Iraq.
A field experiment was carried out during the spring season of 2020 in the experimental field of the College of Agricultural Engineering Sciences - University of Baghdad - Abu Ghraib, to knowing the effect of weed control with propnit herbicide and plant density on the companion weeds growth of sorghum (Inqath cultivar).Randomized complete block design (RCBD) according to split plots at three replications was used, the main plots included three weed control treatments (spraying of propnit herbicide at recommended dose 450-500 ml dunum-1 and half recommended dose 225-250 ml donum-1) in addition to weedy and free weedy treatments, while the sub plots included three plant density(100000, 150000 and 200000 plants ha-1).The results showed that the spraying of propnit at recommended dose recorded the lowest mean of weed density after 25 and 50 days of spraying the herbicide (12.36 and 11.11 weeds m-2) respectively and at the harvest stage (11.89 weeds m-2), and the highest control percentage after 25 and 50 days of spraying the herbicide and at the harvest stage (78.66, 79.80 and 69.41%) respectively. Also, the results indicated that the plant density of 200000 plants ha-1gave the lowest weed density after 50 days of spraying the herbicide (17.25 plants m-2), and atthe harvest stage (12.08 weeds m-2), and gave the highest control percentage at the harvest stage (60.74%). The different combinations between the two studied factors showed a significant effect on the most of the studied traits, the spraying of propnit at recommended dose and sometimes at half recommended dose with high plant density led to an increasing the competition of the crop to the companion weed and reducing weeds density more than the effect of both factors alone.