Degradation and movement of terbuthylazine in soil

Abstract

The persistence and movement of terbuthylazine was studied in two soils in field experiments. The effects of temperature and soil moisture on degradation were further studied in one soil under controlled environment conditions. In the field, terbuthylazine residues were reduced within 6 months to 1% - 5% of that applied with half-lives of 23 and 37 days in a sandy and clay soil respectively. No residues were detected below 10 cm. Temperature had a major effect on degradation while soil water content had very little effect. Under normal conditions of use, terbuthylazine residues should not carry over to the next growing season and are unlikely to contaminate groundwater.