Fate of Insecticides in an Irrigated Field: Azinphosmethyl and Tetradifon Cases

The fates of an organophosphorus (azinphosmethyl) and an organochlorine insecticide (tetradifon) in an irrigated potato field on a loessial sierozem soil were studied. Two amounts of irrigation water (5538 and 4015 m3/ha) were applied; the kinetics of persistence and the movement downward of the two pesticides were followed during the irrigation season. The azinphosmethyl was not transported deeply into the soil by the irrigation water, and it disappeared from the field 30 days after application. The tetradifon was found in trace amounts in the deeper layer of the soil and was persistent throughout the irrigation season. The pesticides' persistence was not affected by the irrigation treatments; however, tetradifon transport into the soil was affected by the amount of water applied. Residues of tetradifon were found in the potato peel.