MODELING THE CONCENTRATION OR DILUTION OF SALINE SOIL-WATER SYSTEMS

For the survey of saline and alkali soils sampling soil solution in si tu is difficult. An alternative is to take soil samples, analyse their extracts and then calculate the chemical composition of the soil solu tion. A model (EXPRESO) has been designed to calculate both the chemic al speciation of electrolyte solution and the exchange equilibrium wit h an adsorbed phase during simulated dilution and concentration. EXPRE SO was validated using reclaimed saline soil samples. Results demonstr ated that EXPRESO is a thermodynamically coherent and mass conservativ e model that allows the calculation of the chemical composition of bot h the soil solution and the exchange complex over a large range of soi l water content (0.250-5 kg water kg(-1) soil). EXPRESO enables the es timation of the chemical composition of the in situ soil solution, giv ing a comprehensive picture of the soil status under different field c onditions.