磷酸三钙几乎完全不溶于水，在稀酸中溶解也极为缓慢。所以，作为肥料，通常得把磷酸三钙转化为过磷酸钙。

• "It is practically insoluble in water and only very slowly soluble in diluted acids, so it is largely converted for fertilizing purposes into superphosphate."