Field-Scale Nutrient Cycling and Sustainability: Comparing Natural and Agricultural Ecosystems

Nutrient cycling — the movement of nutrients from the biotic components of ecosystems to their abiotic components and back again — is an essential function

of all ecosystems (Odum, 1969). Nutrient cycles are never completely closed; all systems receive some external inputs (e.g., from precipitation) and experience some losses to the outside environment (e.g., through denitrification).