Simulatie van twee veldexperimenten naar de uitspoeling van metalaxyl met het model PESTLA

Abstract

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Model calculations with the simulation model PESTLA (PESTicide Leaching and Accumulation) have been performed for the application of metalaxyl on strawberry fields. For these calculations specific field and climate data on the one hand and general information on metalaxyl on the other hand were used as input to the model. The results of the calculations are compared with measured data on the concentration of metalaxyl in the soil profile and in the groundwater. These measured data have been obtained from Ligtermoet Chemie B.V. Leaching of metalaxyl was above the amounts calculated with average values for sorption (K-om) and transformation (DT-50) constants but below the amounts calculated in a worst case scenario (K-om-SE and DT-50 + SE; where SE = standard deviation). Residues in the soil profile and amounts leaching to groundwater were calculated by the model. In one field (field with a higher clay content) metalaxyl appeared in the groundwater sooner than calculated. Possibly this can be attributed to preferential flow of soil moisture through cracks.