The dissipation of bromacil in Humic Luvic Gleysols amended with cow manure was evaluated at two sites in northwestern Alberta from 1984 to 1987. At each site, nine locations were sampled in 4 cm increments from 0 to 40 cm, and analyzed for bromacil, pH, electrical conductivity (EC), and organic carbon (OC). The addition of manure increased values for OC and pH within the surface 16 cm at Site 1 and 24 cm at Site 2. These increases reflected the inherent organic-alkaline nature of the manure itself. Largest increases for both variables occurred between 8 and 16 cm, indicating the predominant depth of cultivation and rooting. Cow manure increased EC values within the surface 4 cm at Site 1 and 12 cm at Site 2. Decreases occurred between 24 and 40 cm at each site, and were caused by leaching. Cow manure promoted microbial degradation of bromacil through increased levels of OC. Bromacil concentrations were lower at the depths where OC percentages were higher. Bromacil concentrations were also reduced throughout the entire 40 cm at Site 2 by leaching. Leaching was restricted at Site 2 by an intermittent high water table, where bromacil concentrations were decreased only within the surface 12 cm. Overall, results of the study show bromacil to be dissipated by two methods: microbial degradation and leaching