Low sorption and fast dissipation of the herbicide saflufenacil in surface soils and subsoils of an eroded prairie landscape.

Saflufenacil partitioning and dissipation were evaluated in soils from an eroded prairie landscape to provide information on its expected environmental fate. Saflufenacil K(d) values followed trends in soil organic carbon content. In surface soils, K(d) values ranged from 0.05 to 0.2 L kg(-1) in the depositional lower slope and from 0.02 to 0.06 L kg(-1) in the eroded upper slope. In subsurface soils, K(d) values were an order of magnitude higher in the lower slope (mean 0.1 L kg(-1)) than in the upper slope (mean 0.01 L kg(-1)). Sorption was slightly higher in samples aged 1-8 weeks compared to freshly spiked soils. Mean dissipation half-lives (DT(50)) were 13 d in surface soils and 32 d in subsurface soils. The observed low sorption and relatively rapid dissipation of saflufenacil suggest that this herbicide will be readily available for degradation or plant uptake in the root zone.