At what pH value, phosphate availability is the highest in the soil

Phosphate availability is highest in the soil at pH 6.5. soil available phosphorus is the fraction of total phosphorus in soil that is readily available for absorption by the roots of the plant.
Approximately 30% - 65% of total soil phosphorus is in organic forms, which are not available to plants, while the remaining 35% - 70% is in inorganic forms.