Modelling the concentration or dilution of saline soil-water systems

Abstract

For the survey of saline and alkali soils sampling soil solution in situ is difficult. An alternative is to take soil sample, analyse their extracts and then calculate the chemical composition of the soil solution. A model (EXPRESO) has been designed to calculate both the chemical speciation of electrolyte solution and the exchange equilibrium with an adsorbed phase during simulated dilution and concentration. EXPRESO was validated using reclaimed saline soil samples. Results demonstrated that EXPRESO is a thermodynamically coherent and mass conservative model that allows the calculation of the chemical composition of both the soil solution and the exchange complex over a large range of soil water content (0.250-5 kg water kg-1 soil). EXPRESO enables the estimation of the chemical composition of the in situ soil solution, giving a comprehensive picture of the soil status under different field conditions.