Productive and qualitative indicators of forage yield of forage sorghum (Sorghum bicolor L.) varieties when controlling associated broadleaf weeds with 2,4-D 72% pre-emergence herbicide

A field experiment was carried out during the spring season of 2023 in a farmer's field in the Kuldarah area of ​​Altun Kopri district in Kirkuk Governorate, with the aim of knowing the effect of 2,4-D 72% herbicide on the growth of broad-leaved weeds accompanying the white corn crop, the dry and green fodder yield of this crop, and the qualitative traits in terms of the percentage of protein and fiber for six varieties of Sorghum (Sorghum bicolor L.) The experiment was applied according to the Randomized Complete Block Design (R.C.B.D.) with three replications, The treatments included (2,4-D herbicide, weed control and weed-free treatment, the varieties were (Buhuth - Giza - Rabeh - Lilo - Enqaz - J). The 2,4-D herbicide was sprayed before emergence using a (16) liter capacity continuous pressure backpack pump at a quantity of 1.5 liters. ha^-1, then it was mixed with the soil to prevent the light effect on the herbicide. The results of the statistical analysis indicated that spraying 2,4-D herbicide before emergence recorded the highest weed inhibition rate, reaching 79.111%, and the lowest weed index rate for green and dry fodder yields, reaching 9.742% and 24.637%, respectively, and an increase in the green and dry fodder yield, reaching 48.427 tons. ha^-1 and 11.495 tons. ha^-1, respectively, the percentage of protein and fiber increased by 8.940% and 53.768% respectively. As for the varieties, the Bohouth variety was superior and recorded the highest weed inhibition rate of 30.889%. The Giza variety was superior in the weed index trait for dry fodder yield and recorded the lowest average weed index of 21.279%. The varieties (J, Giza and Bohouth) were superior in the green fodder trait and recorded 45.079, 44.860 and 44.103 respectively. The interaction coefficients between the study factors showed a noticeable variation in most of the studied traits, as the Bohouth variety combination was superior when controlled with 2,4-D 72% herbicide before germination in the inhibition rate trait and recorded the highest average of 92.667%, as well as the lowest percentage of weed index for dry fodder yield, which reached 10.550%. The dry fodder obtained It reached 13.476 tons. ha^-1, while in terms of qualitative traits, the combination of class (J) with 2,4-D herbicide was superior, as it recorded the highest average of 9.496%.