bioforsk.no Corresponding author: marianne.stenrod@bioforsk.no

1. Testing and comparison of three pesticide risk indicator models under Norwegian conditions A case study in the Skuterud and Heiabekken catchmentsMarianne Stenrød, Heidi E. Heggen, Randi I. Bolli, Ole Martin Eklo Norwegian Institute for Agricultural and Environmental Research Pesticide leaching risk on selected field: Azoxystrobin: HighCyprodinil: LowCyproconazole: MediumDichlorprop: HighDiquat dibromide: LowEthephon: LowFenpropimorph: LowGlyphosate: MediumIoxynil: HighIodosulfuron: LowChlormequat chloride: HighChlorsulfuron: LowMancozeb: HighMCPA: HighMetalaxyl: HighProchloraz: LowPropiconazole: LowTribenuron-methyl: LowTrinexapac-ethyl: Low Figure 3: SWAT-simulation results, based on input data of pesticide use, climatic conditions and soil type and drainage, summarized for 10 years. All pesticides used on the field x soil type (here: silty clay loam) in question are shown with an associated leaching risk. Figure 4: SWAT-simulation results, based on input data of pesticide use, climatic conditions and soil type (Rk8 = silty clay loam, Je3 = sandy soil) and drainage, summarized for 10 years. The leaching risk for the pesticide ioxynil is shown for a particular farm. Marianne Stenrød Heidi E. Heggen Randi I. Bolli Ole Martin Eklo Figure 1. The (four) most used pesticide active ingredients in the Skuterud catchment 1994-2003 (a) and the Heiabekken catchment 1996-2002 (b) Figure 2. The (four) most hazardous (as estimated by the NERI- and EIQ-models) pesticide active ingredients used in the Skuterud catchment 1994-2003 (a) and Heiabekken catchment 1996-2002 (b). www.bioforsk.no Corresponding author: marianne.stenrod@bioforsk.no