Effect of organic matier content on persistence of atrazine

Persistence of atrazine in soils with graded concentration was studied in laboratory conditions during 1998 in field soils of known compositions. Soils having different organic matter contents treated with herbicide as well as untreated were incubated at 25°C for 120 days. Soil samples were taken at 0, 7, 15, 30, 45, 60, 75, 90, 105 and 120 days and persistence of atraline was studied by bioassay technique. Root length of oats was used as bioassay parameter to detect the residues of atrazine. The persistence of atrazine was almost negligible after 30 days in soil having 0.99% OMC, 75 days in soil having 0.72% OMC and 90 days in soil having 0.50% OMC. The results indicated that higher the organic matter content in soils, lesser is the persistence of atrazine in soil and vice-versa.