Persistence and movement of chlorbromuron in potato soil.

Movement and persistence of chlorbromuron applied at rates of 1.5, 3, and 6 kg a.i./ha was studied in a New Brunswick potato soil for one growing season. Most of the chlorbromuron remained in the 0 - 2.5 cm soil depth with slight residues in the 2.5 - 5, 5 - 7.5, and 7.5 - 10 cm depths. After 47 days the chlorbromuron residues had dropped to 40%, then gradually levelled off to 25% at the end of the season. Chlorbromuron was determined directly by electron capture gas chromatography using a short glass column of 3% OV-210.