ABSTRACT
The extent of groundwater contamination mainly depends on the degree to which pesticides leach through the unsaturated zone of soils on which they have been applied. Pesticide movement through the unsaturated zone in tile-drained fields may also be a source of pesticides in surface waters. Knowledge of pesticide movement in soil above the groundwater table is very important. The most important factors influencing pesticide leaching are soil properties, inherent properties of the pesticide molecules, climatic conditions, and management practices.
