Submitted to: American Chemical Society Symposium Series
Publication Type: Book / Chapter
Publication Acceptance Date: 6/28/2001
Publication Date: 2/1/2003
Citation: MULLA, D.J., GOWDA, P., KOSKINEN, W.C., KHAKURAL, B.R., JOHNSON, G., ROBERT, P.C. MODELING THE EFFECT OF PRECISION AGRICULTURE ON PESTICIDE LOSSES TO SURFACE WATERS. ARTHUR, E.A., CLAY, V.E. AND BAREFOOT, A., EDITORS. TERRESTRIAL FIELD DISSIPATION STUDIES: PURPOSE, DESIGN AND INTERPRETATION. AMERICAN CHEMICAL SOCIETY SYMPOSIUM SERIES 842. AMERICAN CHEMICAL SOCIETY, WASHINGTON, DC. 2003. P. 304-317.
Technical Abstract: In this study we evaluated the environmental impacts of spatially variable versus uniform application of acetochlor. Spatially varying rates of acetochlor ranging from 2.0 to 2.7 kg/ha were applied to a 32 ha bare field planted to corn during the Spring of 1998. These rates were varied in accordance with measured soil surface organic matter contents, sorption Kd values, and grassy weed populations. Surface runoff and tile drain leaching losses of acetochlor were measured using automated sampling systems. The Agricultural Drainage and Pesticide Transport (ADAPT) model was calibrated to measured water fluxes, and losses of sediment, nitrate, and acetochlor to surface waters. There was excellent agreement between measured and modeled water fluxes, sediment losses, nitrate losses, and acetochlor losses. Acetochlor losses for the variable rate strategy were 10-18% lower that losses from a uniform application of 2.7 kg/ha.