A field experiment was carried out during the winter season for the year 2021-2022 at the Agricultural Research Station A of the Field Crops Department - College of Agricultural Engineering Sciences- University of Baghdad/ Al-Jadriya. To determine which of the plant densities has the most influence on the weeds associated with the flax crop (Syrian local variety). And to determine the best effect of the Johnson grass (sorghum halepance L.) weed extract, whether alone or in combination with the used Quizalofop- p- Tefuryl herbicide, and to use it in integratTed weed control programs to reduce dependence on herbicides in weed control, Reduce environmental pollution by these herbicides, According to the design of the Randomized Complete Block Design (RCBD). In the order of split plot and with three replications, Such as the first factor, the distance between the row (20, 25, and 30) cm that represents the main plots. Then, the second factor is Control treatments which represent the subplots, (weed free (T1), application Quizalofop-p-Tefuryl at a rate of 2 mL commercial substance (T2), Recommended application rate, Johnson grass extract (stem and leaves) at a rate of 18 L (T3), half the amount of herbicide + half the amount of extract (T4), weedy (T5)). The results showed the following: The distance of 20 cm achieved the lowest dry weight of the weed and the highest average inhibition of 134.57 g/m2 and 49.91%, respectively. While the distance of 30 cm achieved the highest plant height of 78.63 cm, the highest number of main branches in the plant amounted to 5.162 branch/ plant. The highest weight Dry flax plants amounted to 355.21 g/m2. Moreover, the highest percentage of oil was 38.524%. The treatment (T2) achieved the lowest dry weight of the weed and the highest percentage of inhibition amounting to 138.87 g/m2 and 49.91%, respectively. The highest plant height reached 76.92 cm, the highest number of main branches in the plant amounted to 5.158 branch/ plant, and the highest dry weight of flax plants reached 5.158 branch/ plant. 398.61 g/m2 and the highest percentage of oil was 37.35%. The effect of the interaction between the two study factors was significant in most of the traits under study. As the distance of 20 cm with the T2 treatment achieved the lowest dry weight of the weed amounted to 124.53 g/m2 and the highest inhibition rate of 52.35%. While the interaction between the distance of 30 cm and T2 achieved the highest plant height of 80.04 cm, the highest average number of main branches reached 5.833 branch/ plant, and the highest dry weight of flax plants reached 398.61 g/m2 and achieved the highest percentage of oil amounted to 39.847%.

A field experiment was carried out to determine the best effect of Johnson grass extract, alone or in combination with Quizalofop-p-Tefuryl herbicide, to achieve the benefit of their integration into weed control programs to reduce reliance on herbicides in controlling weeds, increasing yield and reducing environmental pollution by these herbicides. The randomized complete block design (RCBD) with the split plot arrangement by three replicates was applied, the distance between the rows (20, 25 and 30 cm) represents the main plots. The control treatments : weed-free (T1), application Quizalofop-p-Tefuryl at rate 2 ml/l (T2), Johnson grass extract at rate 18 l/ha (T3), half herbicide amount + half extract amount (T4) and weedy treatment (T5) , represent the sub-plots . The results showed that of distance 20 cm achieved lowest density of companion weeds (52.20 weeds/m2) and highest percentage of weed control (50.42) after 60 days of application, and highest seed yield, oil yield reached 1.781 and 0.675 t/ha, respectively. The distance 30 cm achieved highest number of capsules (14.790 capsules/plant) seeds (8.337 seeds/capsule) and highest weight of 1000 seeds reaching 7.379 g. Application of Quizalofop-p-Tefuryl (T2) achieved lowest weed density (54.78 weeds/m2), highest weed control percentage (52.22) after 60 days of application. Besides, highest number of capsules (14.956 capsules/plant), seeds were (8.580 seeds/capsule), highest weight of 1000 seeds was 7.611 g, and highest seed yield , oil yield reached 1.779 and 0.7113 t/ha, respectively. Distance 20 cm with treatment (T2) achieved lowest number of weeds reaching (44.67 weeds/m2), highest percentage of weed control (57.59) after 60 days of application, highest seed yield, oil yield reached 2.067 and 0.7267 t/ha, respectively. Distance 30 cm and treatment (T2) achieved highest number of capsules (16.05 capsules/plant), seeds (8.580 seeds/capsule) and highest weight of 1000 seeds reaching 7.873 g.