Leaching 
The rate of diffusion of herbicides may be calculated from 
Fick's diffusion equation: 

mass of herbicide 
diffusion coefficient 
surface area of herbicide 
solubility of herbicide in water 
final concentration of dissolved herbicide 
thickness of diffusion layer 
time in seconds 
274 
* U, S. GOVERNMENT PRINTING OFFICE : 1966 © - 219-423 
