A coupled model representing volatilisation and sorption of soil incorporated herbicides

A coupled model representing simultaneous sorption and volatilisation of so il applied herbicides is presented in this work. The model accounts for kin etic sorption-desorption-processes of the herbicides and a variable volatil isation flux depending on solute concentration in water. Several experiment s using loamy and sandy soils were performed under laboratory conditions wi th the herbicide Terbutryn, at two different temperatures (15 degrees C and 25 degrees C). Other experimental conditions such as air humidity and temp erature were controlled. Despite the simplicity of the model, it was shown to be an efficient tool for the analysis and interpretation of the experime nts performed in volatilisation chambers. The physical interpretation of th e three model parameters is explained and the independent estimation of the parameters for a particular herbicide is discussed.