Modeling pesticide losses with surface runoff in Germany

A model has been developed which estimates relative pesticide losses with s urface runoff for all of Germany. The 42 active ingredients considered in t his study were chosen according to their annual sales in 1993 (herbicides, fungicides > 100 t year(-1), insecticides > 50 t year(-1)). After the const ruction of a nationwide data base on pesticide application rates, the runof f losses of pesticides were calculated by incorporating various spatial dat a sets on climate, soil, land use and other topics that have significant ef fects on pesticide runoff from fields. Results for the cumulative loss of 4 2 active ingredients applied in 11 field crops, orchards and vineyards are presented in digital raster maps (100 x 100 m). The model enables both a vi sualization of the spatial distribution of runoff risk and an assessment of the potential pollution levels originating from certain crops in specified application periods. Due to the scale of the studied area studied, the mod el development had to follow a strictly stochastic approach which contains some notable uncertainties. The lack of reliable information on the behavio ur of the pesticides under site specific conditions constitutes the most im portant limitation. (C) 1998 Elsevier Science B.V. All rights reserved.