Why can protozoans increase plant growth in soils?

Protozoans enhance plant growth in soils primarily by regulating bacterial populations and recycling essential nutrients.1

By grazing on soil bacteria, protozoans maintain these bacterial communities in a state of physiological youth, meaning they remain in an active, rapid growth phase. This process significantly increases the rate at which bacteria decompose dead organic matter, which is a critical step in making nutrients available to plants.12

Furthermore, as a direct result of their metabolism, protozoans excrete nitrogen and phosphorus in the form of ammonium and orthophosphate. Because these nutrients are released in forms that plants can readily absorb, the presence of protozoans effectively boosts soil fertility and supports healthier plant development.12