Performance and Persistence of Atrazine

Field experiments were conducted from 1967 to 1971 to determine the influence of incorporation and time of application on the performance and persistence of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine]. Both grass and broadleaf weeds were effectively controlled by atrazine on all dates of application. Both the 2.8 and 5.6 kg/ha rates were effective as preplant incorporated or preemergence treatments. Persistence of atrazine did not differ with respect to method of application. Applications of atrazine made in April and May were degraded more rapidly than were applications made in February and March. Loss curves generally corresponded to a first-order reaction with atrazine showing an average half-life of 20 days from February to July.