English Abstract 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.
