Submitted to: American Chemical Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/15/2000
Publication Date: N/A
Technical Abstract: Precision agriculture is an approach that allows the rate of pesticide applied to a field to be varied in response to spatial patterns in weed populations, soil organic matter content, and pesticide sorption or dissipation characteristics. It is hypothesized that this approach allows effective weed control, maintains crop productivity, reduces the environmental impacts of pesticides, and increases farm profitability. Spatially varying rates of acetochlor ranging from 1.96 to 2.70 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 acetochlor to surface waters. The model was then used to evaluate differences between the losses of acetochlor to surface waters with the variable rate strategy versus a hypothetical uniform rate strategy. The sensitivity of the model to spatial variability in various input parameters is discussed.