One goal of every field pesticide volatility flux study should be to measure as many environmental parameters as possible to aid in the development of models to predict volatilization fluxes for current-use pesticides from all crops grown throughout the country. Such a database and modeling effort does not currently exist. The transfer of pesticides from soil, field crops, and orchards to the atmosphere is governed primarily by the chemical characteristics of the pesticide and by the atmospheric turbulence generated by wind moving over that surface. If the source strength is known, estimating volatilization flux is a function of wind speed gradients and atmospheric stability. Knowing the source strength, however, requires an understanding of how the pesticide moves through the soil, crop, or orchard to the surface and is critical in modeling the volatilization process. Modeling efforts need to be verified with actual field data, but currently available pesticide flux data are limited and mostly from fallow soil. Canopy structures, function, and microclimates within most field crops and orchards are very complex. Understanding their complexity is critical to being able to model pesticide movement through the canopies. Knowledge and understanding of the physical and physiological attributes of plant canopies, their spatial and temporal variability, and wind speed and temperature gradients within the canopies are also needed. In addition, how the pesticide is distributed within the canopy as well as how it interacts with leaves, stems, branches, and soil are important parameters. This presentation will discuss the field measurements needed to develop a robust model to estimate pesticide volatilization fluxes from various crops, then using these field data to fine-tune the model in order to predict the next field experiment, and continuing in an iterative manner until the model can reliably predict volatilization fluxes from any crop type or surface.

Considerations for estimating pesticide volatilization fluxes from various crops

246th National Meeting (2013)

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