Laboratory Degradation Studies of 14C-Atrazine and -Isoproturon in Soil from Sugarcane Cultivated Fields Under Kenyan Tropical Conditions

摘要

A study to compare the degradation rates of atrazine (6-chloro-N 2-ethyl-N 4-isopropyl-1,3,5-triazine-2,4-diammine) and isoproturon [3-(4-isopropylphenyl)-1,1-dimethylurea] in soils from sugarcane fields with different practices of herbicides application was carried out. 14C-atrazine was poorly mineralized to 14CO₂ (1.10% ± 0.22%) after 139 days of incubation in soil without previous exposure to atrazine. In the same soil also with no previous isoproturon exposure isoproturon was mineralized to 14CO₂ by 7.70% ± 0.94%. Atrazine mineralization after 98 days was 13.4% ± 0.30% in soil which discontinued the use of atrazine in 1997 while it was 89.9% ± 1.23% in soil in which atrazine is currently being used. The isoproturon mineralization values were 7.24% ± 0.85% and 22.97% ± 0.96% in soil which discontinued atrazine and soil currently using atrazine, respectively. Keywords Soil - Mineralization - Isoproturon - Atrazine