|BARBER, BRIAN - University Of Minnesota|
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/2/2012
Publication Date: 10/2/2012
Citation: Papiernik, S.K., Koskinen, W.C., Barber, B.L. 2012. Low sorption and fast dissipation of the herbicide saflufenacil in surface soils and subsoils of an eroded prairie landscape. Journal of Agricultural and Food Chemistry. 60:10936-10941. DOI: 10.1021/jf303271p.
Interpretive Summary: Saflufenacil is a new herbicide used in corn, soybean, and other crops. To assess its expected effectiveness and behavior in the environment, we conducted a series of laboratory studies to measure the retention and degradation of saflufenacil in soil. Regulators, industry, and other scientists can use this information to evaluate saflufenacil’s potential for weed control, carryover, leaching, and runoff in a variety of soils in which it is likely to be used. Results showed that saflufenacil interacts little with soils typical of the northern U.S. Corn Belt. Saflufenacil dissipated fairly quickly in our studies, with only half of the herbicide remaining two weeks after it was applied to surface soil. Based on these results, we expect that herbicide interactions with soil will not limit saflufenacil’s degradation or plant uptake in the root zone. Under typical conditions in the U.S. Corn Belt, saflufenacil is not likely to carryover and damage following crops. Its low retention in soil could make saflufenacil prone to leaching shortly after application so, like all agricultural chemicals, it should be carefully used to avoid contaminating water supplies.
Technical Abstract: Saflufenacil partitioning and dissipation was evaluated in soils from an eroded prairie landscape to provide information on its expected environmental fate. Saflufenacil Kd values followed trends in soil organic carbon content. In surface soils, Kd 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, Kd 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 to 8 weeks compared to freshly-spiked soils. Mean dissipation half-lives (DT50) 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.