CYANAZINE DISSIPATION AS INFLUENCED BY SOIL PROPERTIES

A laboratory experiment was performed to study the aerobic degradation of cyanazine in six soils ranging in pH from 5.3 to 8.1. Atrazine degradation was evaluated in one soil to provide a reference for longevity values. Soil half-life values for cyanazine ranged from 5.2 to 29.7 days. Cyanazine was more persistent in the moderately acidic soils. The rapid degradation of cyanazine in the neutral to slightly basic soils was due to hydrolysis of the nitrile group. Cyanazine amide and cyanazine acid were the major degradation products. The soil half-life value for atrazine was approximately 3.4 times greater than that of cyanazine in a sandy loam soil. Dissipation of ring-labeled [C-14]cyanazine or ring-labeled [C-14]atrazine by volatilization or (CO2)-C-14 evolution was not observed.