Plants of chickpea and durum wheat were cultivated as sole-­‐crop and intercrop in a rhizobox device according to a substitutive design. Unplanted soil was used as a control treatment. The soil used was a non carbonated Luvisol with a neutral pH. Plants were harvested at the chickpea flowering stage. The pH, P availability and dissolved Ca were measured in soil as extracted by water and CaCl2 (1 and 10 mM). A set of thermodynamic models were used (i.e. CD MUSIC; Nica Donnan; ion exchange) to simulate and understand measured P availability variations in each treatment.