Persistence and Movement of 2,3,6-TBA in Soil

Abstract

Persistence and movement of 2,3,6-trichlorobenzoic acid (2,3,6-TBA) in a silty clay loam soil was studied. Single applications of 16 lb/A 2,3,6-TBA were made to field plots on 21 dates from 1955 to 1965. All treated plots were sampled to a depth of 8 ft in 1966, and a few were sampled to a depth of 11 ft. One-foot increments of soil were bioassayed to determine presence of the herbicide. Variation in amount and depth of penetration of 2,3,6-TBA was noted, but the herbicide had persisted in the soil 11 years. Persistence and movement could not be related to moisture before or after treatment, temperature after treatment, or, except for treatments applied in 1964 and 1965, time between treatments and sampling. Residues from fall applications appeared to be slightly greater than those from spring or summer applications.