This is because, phosphorus is not in gaseous state but it is liquid at normal temperature, therefore it cannot be found in the air. It is cycle through water,soil or sediments. The major source of phosphorus in the phosphorus cycle is the rock. Rock contain phosphorus and phosphorus I'd gotten from rocks through weathering. Weathering is the disintegration of rocks into sediments or smaller particles. This is released into the soil after weathering.
