Understanding Trends in Pesticide Volatilization from Agricultural Fields Using the Pesticide Loss via Volatilization Model.

ABSTRACT

The Pesticide Loss via Volatilization model was developed to predict and understand pesticide volatilization rates from a planted agricultural field. The model allows the user to adjust the properties of the pesticide, various soil and plant descriptors, and climatic conditions. A useful output from the model is the 24 h cumulative percentage volatilization (CPV24h) loss. The model was validated by comparing modeled CPV24h values to measured ones compiled from the literature. Sensitivity analysis showed that the plant intercept fraction (%I), leaf area index (LAI), and leaf height (hleaf) strongly affect volatilization rates of plant- and soil-sorbed pesticides whereas LAI, hleaf, and the percent of water on the plant surface strongly affect more water-soluble pesticides. The model showed that most pesticides volatilize more readily from plants than from soil and that volatilization rates vary significantly for certain pesticides (but not all) when applied to plants at different growth stages and for different species of plants. Results are displayed on chemical space diagrams to paint a clear picture of how CPV24h varies for chemicals with different properties under different conditions.