Submitted to: American Chemical Society National Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/12/2011
Publication Date: 8/28/2011
Citation: Potter, T.L., White Jr, P.M., Lima, I.M. 2011. Herbicide sorption in a biochar-amended coastal plain soil under conventional and conservation tillage management [abstract]. American Chemical Society National Meeting. August 28-September 1, 2011.
Technical Abstract: Commercial cropping systems worldwide depend on herbicides for weed control. “Soil residual herbicides” applied to soil prior to crop emergence are an important class of these products. Sorption of active ingredients by soil colloids impacts both weed control and soil persistence. Soil organic matter is typically the principal sorption site. Biochar addition to soil increases soil organic matter and will likely increase soil residual herbicide adsorption. There is potential for positive and negative consequences including increased or decreased efficacy and or soil carry-over and toxicity to subsequent crops. We investigated biochar impact on soil sorption of three soil residual herbicides, metolachlor, fomesafen, and pendimethalin in a loamy sand soil widely used in the Southeastern USA for cotton (Gossypium hirsutum) production. Koc’s ranged from 50 to 16000 mL g-1. The biochar, produced by pine wood chip pyrolysis at 500oC, was added at rates designed to double the soil organic carbon content. Batch equilibrium studies showed that biochar increased sorption of all three compounds by about 50%. Implications for biochar use on herbicide efficacy and fate in this soil under conventional and conservation tillage management will be discussed.