Is organic matter alone sufficient to predict isoproturon sorption in calcareous soils?

► Isoproturon adsorption was studied on eleven soils. ► OM and calcite contents have an antagonistic effect towards pesticide retention. ► Rt (calcite/OM) and OM are the main parameters governing isoproturon adsorption. ► A simple empirical model function of OM and Rt describes isoproturon adsorption.