Estimate of the leaching of atrazine and DEA transported in runoff effluents under a vegetative filter strip and a maize crop installed down-slope

Abstract

Vegetative filter strip (VFS) can efficiently remove pollutants from surface water runoff by infiltration but the questions remain concerning the following leaching of trapped pesticides. The objective of this study was to evaluate the leaching of atrazine and desethylatrazine (DEA) transported in runoff effluents and trapped by a VFS and to compare the results with the losses under a maize crop installed down-slope. The soil solution was sampled using porous cups installed at 120 cm depth at the edge of a VFS established downhill from a maize plot and in the maize plot. Drainage volumes were calculated by a generic crop model. The results show that losses of pesticides by leaching were approximately the same under VFS and maize plot. Leaching occurred mainly outside the growth season. Calculated leaching amounts of DEA were twice those of atrazine. Annual losses of atrazine plus DEA represent 0.5 % of the amounts applied on the maize.