SIMULATION OF BENTAZON LEACHING IN SANDY LOAM SOIL FROM MELLBY (SWEDEN) WITH THE PESTLA MODEL

Results of a lysimeter study on bentazon leaching in a sandy loam soil from Mellby (Sweden) were used to test the PESTLA model. To obtain a good description of the measured amounts of drainage water, the potential evapotranspiration rate (based on the Penman equation) had to be multiplied by 1.5 to 2. This comparatively large increase in potential evapotranspiration is probably the result of the surroundings of the lysimeter being dry for most of the experimental period. Using sorption parameters estimated from literature data resulted in the calculated leaching of bentazon to be much higher than the measured leaching. Using sorption parameters based on measured bentazon adsorption to the sandy loam soil resulted in a good explanation of the observed leaching of bentazon by the model.