Question

Definition: this is the cycling of nutrients among soil, litter, plant roots, and above-ground plant parts.

Answer 1

the answer is internal cycling

Answer 2

Plants take up the nutrients from the air, water and soil around them. This circulation of nutrients is termed as INTERNAL CYCLING.

Since, nutrients get transformed into one form from another, plants take up the nutrients when these organic matter decompose and add into the soil. Plants then take them up through the roots. Organisms in soil, like microbes and earthworms, help in decomposing the organic matter into simpler molecules, which are then absorbed by plant roots.