EFFECT OF FIVE ADJUVANTS ON THE ACETOCHLOR ACTION ON PURSLAN (Portulaca oleracea) AND COCKLEBUR (Xanthium brasilicum) AND ITS PERSISTENCE IN SOIL .

The results of studying the effect of acetochlor and its mixtures on the emergence of Portulaca oleracea weed revealed that in general the least effective treatments were acetochlor mixture with citric acid with 2.74 weeds/ m² as a mean, followed by acetochlor alone (2.30). While the most effective treatments resulting in low mean were acetochlor+ phosphoric acid (0.52), followed by the other treatments.
For X. brasilicum the mean values showed that acetochlor half dose with phosphoric acid, with palm oil and with capl 2 crude oil were the most effective mixtures with (0.19, 0.41 and 0.30 weed /m²). The mixture with citric acid was the least effective (0.96 weeds /m²) beside acetochlor alone with (1.96 weeds /m²) comparing with 4.33 weeds / m^2. While full dose of acetochlor was more effective on inhibiting the emergence of both tested weeds. Acetochlor mixture with phosphoric acid was the most effective mixture in suppressing both weeds emergence.
In general the fresh weight obtained from treatment with half recommended dose was higher than that obtained on treatment with full dose. Acetochlor alone and its mixture with citric acid resulted in fresh weight higher than all the other treatments as for the full dose and its half of the two tested weeds. There was very high % germination of the cucumber as a test plant in the treated soil layer 5 – 10 cm. This may be due to the effect of the tested adjuvants except for citric acid which didn’t show the same effect.
The persistence of acetochlor with phosphoric acid was higher than all the other treatments during the experiment interval including acetochlor alone. The highest RL₅₀ value was that of acetochlor with phosphoric acid (27.73 days), while the lowest was that of acetochlor with arabic gum (6.56 days).