A laboratory degradation experiment was carried out as a factorial arrangement. Experimental factors were two soil textures (Sandy loam, Silty clay), three temperatures (10, 20 and 30oC) and four incubation periods (0, 20, 40 and 60 days) in a completely randomized design with three replications. Results showed that soil texture and temperature had significant effects on the degradation rates of atrazine. Highest and lowest degradation rates occurred in the sandy loam soil (30oC) and the silty clay soil (10oC) with degradation rate coefficients of 0.0077 and 0.001, respectively. The half-life of atrazine in the silty clay was lower than that in the sandy loam. At 10, 20 and 30oC atrazine’s half-life was 693, 364.5, 138.6 and 277.2, 157.5, 90 days in the sandy loam and the silty clay, respectively. It seems that atrazine persistence is lower in clay soils and temperate areas.

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