Phosphorus cycle is the biogeochemical cycle that describes the movement of element phosphorus through the various components of Earth. Phosphorus moves through the lithosphere, biosphere and hydrosphere in various chemical forms. In a nutrient cycle, it is impossible to describe any step as a first phase or step, since various steps combine to form a cycle and each step is dependent on the previous step and governs the subsequent step. Thus, we can look at all the steps that combine together to form the cycle.

The phosphorus in minerals and rocks is dissolved by rain and reaches soil and water. From there, plants and animals take it up and incorporate it in their bodies. When these organisms die, their bodies decompose and phosphorus is returned back to soil. Finally, this phosphorus is taken to oceans by water, where it sediments and becomes part of the rock; thus completing the cycle.

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