Rock phosphate is a suitable fertiliser for soils which are

Rock phosphate is a suitable fertilizer for Acidic soils.
Rock phosphate (RP) is an important natural source of P and is used as raw material for the production of chemical phosphatic fertilizers.
The direct application of RP has been found suitable for acidic soils as low pH helps to solubilize the RP and increases the available form of P to the plants.
Use of phosphate rock is not usually recommended when the soil pH exceeds 5.5.