The Nitrogen Cycle

The nitrogen cycle explains how nitrogen is recycled between the soil, plants and animals.

Plants use nitrogen in the form of nitrates to make the amino acids in proteins. Nitrates are absorbed from the soil by the roots of plants. Plants use nitrates to build up proteins which may then be eaten by animals.

Animal waste and dead plants and animals are broken down by decomposers which returns nitrogen to the soil as ammonia. Bacteria and fungi are decomposers.