The volatilization of pesticides following soil application can be predicted from considerations of the physical and chemical principles controlling concentrations at the soil surface. When these concentrations are maintained at a relatively high level, volatilization losses will be determined by the pesticide vapor pressure as modified by adsorptive interactions with the soil. For pesticides which have been mixed with the soil or when volatilization has been proceeding for a time so that concentrations at the soil surface are low, volatilization rates will be determined by the rate at which pesticides move through the soil to the soil surface. Under conditions when mass flow in liquid water is negligible, volatilization rates are predictable using solutions to the diffusion equations. When mass flow is operative the prediction of rates of volatilization are more complex. A computer model has been developed combining both diffusion and mass flow for predicting the volatilization of soil-incorporated pesticides.

"Grant no. 801835; Program element 1BB039; ROAP/TASK 21 AYP 17." Report prepared by Department of Soil Science and Agricultural Engineering, University of California, Riverside, California. Includes bibliographical references (pages 52-54).