Following are the three aspects of nutrient cycles:
(a) Nutrients input-
Nutrients are supplied to the ecosystem via external resources for further use in biological processes.
(b) Nutrients output-
Nutrients move out of the ecosystem, and some nutrients become inputs for another ecosystem.
(c) Internal nutrient cycling-
Decomposers such as bacteria, fungi and actinomycetes continuously regenerate nutrients in the soil by the process of decomposition and store them in the forms that are available to plants.