Measurement and conceptual modelling of herbicide transport to field drains in a heavy clay soil with implications for catchment-scale water quality management

► The transport of propyzamide and carbetamide to field drains was monitored. ► Both herbicides were transported rapidly in events following application. ► Observed data were explained with the help of a simple conceptual model. ► Drainflow seems to be the dominant herbicide transport pathway in this catchment.