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DEVELOPMENT AND VALIDATION OF A MECHANISTIC GROUND SPRAYER MODEL
Citation:
Teske, M. E., N. J. Ewing, N. B. Birchfield, AND S L. Bird. DEVELOPMENT AND VALIDATION OF A MECHANISTIC GROUND SPRAYER MODEL. Presented at 2004 American Society of Agricultural Engineers/Canadian Society of Agricultural Engineering International Meeting, Ottawa, Canada, August 1-4, 2004.
Impact/Purpose:
Extend existing model technologies to accommodate the full range of transport, fate and food chain contamination pathways, and their biogeographical variants, present in agricultural landscapes and watersheds. Assemble the range of datasets needed to execute risk assessments with appropriate geographic specificity in support of pesticide safety evaluations. Develop software integration technologies, user interfaces, and reporting capabilities for direct application to the EPA risk assessment paradigm in a statistical and probabilistic decision framework.
Description:
In the last ten years the Spray Drift Task Force (SDTF), U.S. Environmental Protection Agency (EPA), USDA Agricultural Research Service, and USDA Forest Service cooperated in the refinement and evaluation of a mechanistically-based aerial spray model (contained within AGDISP and AgDRIFT). This model was validated with an extensive set of aerial field trials conducted by the SDTF, and is now used by the EPA for pesticide risk assessments. Building on previous work, the authors have developed a companion model for ground-based pesticide applications that extends the capabilities of the empirical ground sprayer model contained in AgDRIFT. Because the AgDRIFT ground sprayer model is empirically based on a data set with a limited range of ground sprayer operational conditions, current AgDRIFT ground sprayer predictions are limited to estimating downwind deposition from one of four application scenarios (two release heights and two atomization spectra). With the development of a new mechanistic ground sprayer model, users will have more flexibility in selecting release height, nozzle type, tank mix properties, crosswind, temperature and relative humidity, number of swaths, etc. This paper will present the algorithms of the complete mechanistic model, and compare model predictions with downwind deposition measurements from previously conducted ground sprayer field studies.