Beschreibung:
<jats:title>Abstract</jats:title><jats:p>The herbicide atrazine [2‐chloro‐4‐ethylamino‐6‐isopropylamino‐1,3,5‐triazine] was applied to corn at recommended rates over a period of 18 years until 1988. The investigated field was sampled down to a depth of 10 m in 1989 and 1991. In both years residues of atrazine were determined down to 10 m depth by HPLC‐analysis of soil extracts in concentrations of up to 12 μg/kg. Batch‐experiments were conducted to establish sorption isotherms of various soil layers. Numerical simulations of the migration of atrazine, based on the Richards‐equation and the convection‐dispersion‐equation with first‐order degradation were performed and compared to the measurements.</jats:p><jats:p>Depth‐dependent distribution of atrazine residues could be roughly reproduced by calculations, but the calculated depth‐profiles of atrazine concentrations varied strongly within the variability of the sensitive parameters. The deterministic model used was therefore not able to predict the amount of pesticide residues in groundwater recharge precisely.</jats:p>