The ability to accurately predict the mobility of a soil-applied herbicide is important to product registration and recommendations for environmentally safe use. Commonly, mobility is affected by time-dependent sorption processes. Parameters for such nonequilibrium sorption may be conveniently determined from batch kinetic studies; however, applicability of these parameters for subsequent use in transport modeling must be verified. The objective of this study, therefore, was to determine whether batch kinetic data were appropriate for predicting nonequilibrium sorption during alachlor [2-chIoro-N-(2,6-diethylphenyl)-N-(methoxymethyl)-acetamide] transport in Dundee silt loam soil. Batch (solution and extraction) data previously generated in this laboratory were used to determine sorption parameters for two- or three-site equilibrium/kinetic sorption models. Predictions of alachlor mobility generated from the corresponding transport models were then compared with miscible displacement data. Use of sorption parameters determined from batch solution data alone resulted in only qualitative predictions of alachlor movement. However, more accurate predictions were obtained if sorption parameters were based on both soil extraction and soil solution data.