Multi‐ion miscible displacement experiments were conducted with saturated soil columns under steady‐state flow conditions. The experiments were carried out with four ionic species (Ca2 Na+, SO42 and CI and the columns were 30 cm long. The experimental data were used to evaluate the multi‐ion convective‐dispersive miscible displacement model, developed in Part I of this study. Some parameters needed for this model were estimated with simplex and nonlinear least‐square fitting methods. It was found that the model described the observed break through curves satisfactorily, when the soil matrix‐solute interaction was described as an exchange process instead of an adsorption process.

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A coupled convective-dispersive model was developed' to describe the solute movement of four ionic species (Ca2+. Na'. SO: and C l ) through soil. The model considers precipitation and dissolution of calcium sulfate as well as cation exchange or adsorption during steady-state water flow in saturated soil columns. With the model hypothetical miscible displacement expenments were carried out. The governing partial differential equations were solved nunierically with an implicit Crank-Nicolson scheme. With the use of obtained results the effect of various model parameters on the shape of the calculated breakthrough curves was investigated. It was found that the processes of dissolution and precipilation, cation exchange or adsorption do have a definite influence on the shape of the breahthhrugh curves.