Nitrogen Cycle

**Definition:** The circulation of nitrogen in nature, consisting of a cycle of biochemical reactions in which atmospheric nitrogen is compounded, dissolved in rain, and deposited in the soil, where it is assimilated and metabolized by animals, plants, bacteria, and fungi, eventually returning to the atmosphere by bacterial decomposition of organic matter.

**Tree numbers:** - G02.111.587 - G02.607.560 - G16.500.768