A coupled model representing volatilisation and sorption of soil incorporated herbicides

A coupled model representing simultaneous sorption and volatilisation of soil applied herbicides is presented in this work. The model accounts for kinetic sorption-desorption-processes of the herbicides and a variable volatilisation flux depending on solute concentration in water. Several experiments using loamy and sandy soils were performed under laboratory conditions with the herbicide Terbutryn, at two different temperatures (15°C and 25°C Other experimental conditions such as air humidity and temperature were controlled. Despite the simplicity of the model, it was shown to be an efficient tool for the analysis and interpretation of the experiments performed in volatilisation chambers. The physical interpretation of the three model parameters is explained and the independent estimation of the parameters for a particular herbicide is discussed.