SIMAZINE PERSISTENCE IN SOIL AND EFFECTS OF ITS RESIDUE ON CROPS

Abstract

When 4.48 kg/ha of simazine (2-chloro-4,6-bis(ethylamino)-s-triazine) was incorporated with soil to a depth of 15 cm, 53, 40 and 18% was detected at 18, 63, and 161 days, respectively, following which there was a gradual decrease to 1.5% at 690 days. When crops were grown the year after application and the soil contained 0.18 ppm simazine, no residue was detected in corn (Zea mays L.), oats (Avena sativa L.) or beans (Phaseolus vulgaris L.), but the latter two crops were injured and Swiss chard (Beta vulgaris var. cicla L.) did not grow. There was slight toxicity to oats planted 2 yr after application when the soil contained 0.03 ppm simazine.