Soil Persistence of Atrazine and Cyanazine

Abstract

The persistence of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] and cyanazine {2-[[4-chloro-6-(ethylamino)-s-triazin-2-yl] amino]-2-methylpropionitrile} both applied at 2.24 and 4.48 kg/ha was studied in the field on two soils. A greenhouse bioassay using cucumber (Cucumis sativusL. ‘Wisconsin SMR-18′) showed no reduction in growth when plants were grown in soil taken from cyanazine and atrazine treatments at the end of the season. Similarly, fall-sown rye (Secale cerealeL.) was not injured. The yields of transplanted tomatoes (Lycopersicum esculentumL. ‘Campbell 28′) and transplanted watermelons (Citrullus vulgaris‘Crimson Sweet’) were not significantly reduced when grown 1 yr after the initial application of either herbicide.