Abstract

                                Laterite soil had the highest persistence of Atrazine followed by black and red soils in the decreasing order. Among black soils, soil which had alkaline reaction (pH) exhibi- ted longer persistence. The inhibition of soil microbes at high pH might be the reason for lower rate of Atrazine degradation. The faster rate of Atrazine degradation was due to low clay and organic matter contents, Laterite soils which had 4.29% of organic mattor recorded the highest persistence of Atrazine. Because of higher absorption and low rate of desorption, the amount of Atrazine available for chemical and microbial degradation would be much less in laterite soil resulting in longer persistence. The present study also revealed that under field conditions Atrazine persisted in a black clay loam soil for a period of 2 months.

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