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United States Department of Agriculture

Agricultural Research Service

Title: Characterization of Dicamba and An Isoxaflutole Degradate Sorption in Unsaturated Soil

Authors
item Stephens, B - UNIV OF MINNESOTA
item Koskinen, William
item Ochsner, Tyson
item Kookana, R - CSIRO AUSTRALIA

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 23, 2004
Publication Date: November 1, 2004
Citation: Stephens, B.M., Koskinen, W.C., Ochsner, T.E., Kookana, R.S. 2004. Characterization of dicamba and an isoxaflutole degradate sorption in unsaturated soil [CD-ROM]. In: ASA-CSSA-SSSA Proceedings. ASA-CSSA-SSSA Annual Meeting Abstracts, November 1-5, 2004, Seattle, WA.

Technical Abstract: When analyzing the sorption characteristics of unstable and weakly sorbing chemicals, batch methods tend to yield a higher margin of error attributable to losses by degradation or transformation. Consequently, this study employs an unsaturated, one-dimensional horizontal flow method to determine the sorption of dicamba and isoxaflutole's principle degradate, DKN. A 20-cm acrylic column was packed with soils varying in texture that had been uniformly treated with 14C-labeled chemical. While varying both initial soil moisture contents and flow rates, thehorizontal infiltration experiments were conducted to examine their effects on sorption characteristics. A sorption coefficient was ascertained using moisture contents and solute concentrations in relation to the "plane of separation" along the column. Similar sorption coefficients were obtained for the chemicals in silt loam and sand soils with the one-dimensionalflow method as compared to the batch equilibration method. This demonstrates that to determine sorption coefficients for labile, hydrophilic pesticides an unsaturated flow, horizontal column may be a suitable alternative to the batch method.

Last Modified: 4/19/2014