The main objective of the current work is to study the effect of partial acidulation with Triple super phosphate (TSP) on the adsorption, desorption and fixation of phosphate ions and the factors affecting it (diameter of phosphate rock (PR) partially acidulated at the range and rate of application). Comparing the amounts of adsorbed P, results indicated that adsorbed phosphate increased gradually with increasing the rate of application. The relative increase for the P rates were 44.38, 70.34, 67.48, 59.18 and 40.96% for the rates of 100, 200, 300, 400 and 500 mg P kg-1 , respectively. Concerning the effect of acidulation by increasing the rate of TSP application, results showed decreasing the values of adsorbed P and increasing the values of desorbed P. This effect was true for all rates of P applications (100, 200, 300, 400 and 500 mg P kg-1 ). Regarding the effect of particle diameter of Abou-Tartour PR, results revealed that using the rates of 100, 200 and 300 mg P kg-1 , the values of adsorbed P increased and also, the desorbed P slightly increased. In addition, decreasing the particle diameter from 500 µm to ˂100 nano, caused a relative decrease in fixed P at the rates of applied P (400 and 500 mg kg-1 ). The values of the desorbed of the previously adsorbed P decreased with increasing rate of application. Phosphate adsorption efficiency (PAE %) and P desorption efficiency (PDE%) were clearly affected by acidulation with TSP and particle diameter of investigated Abou-Tartour PR.