Phosphorus adsorption evaluation for fertilizer recommendation on three calcareous soils of Karaj region, Iran

The variability of phosphorus concentration in soil solution as adsorption point of view by different minerals could be use for phosphorus recommendation. Identity of phosphorus adsorption on mineral surfaces could be studied by different equations, which their suitability depends on the soil characteristics and the aim of research. But the main concept is based on to equilibrate the soils with electrolyte solution containing different phosphorus concentration in a distinct time and temperature. In this study, three calcareous soil samples (with 7, 4 and percentages CaCO), fine grinded (