The third tropic level of the soil food web are the shredders, predators, and grazers. Bacteria and fungal feeding nematodes, protozoa, arthropods fall into this level .
This is where nutrients are made plant available!
Protozoa's Role in the Soil Food Web
We have learned that bacteria in the soil are the foundation of large food source. Bacteria rapidly reproduce which can lead to bacteria dominated soils. And as we know, soils that are bacterially dominated grow weeds REALLY well. Controlling the bacteria population is important for gardeners and farmers. This is where protozoa shine.
Protozoa eat 10,000 bacteria a day! They are experts at keeping the bacterial populations in check. The consumption of bacteria results in the release of plant available nutrients. You will often hear this referred to as “the poop loop”.
As in any self sustaining system, predators are also prey. Protozoa are the food for microarthropods, macroarthropods, earthworms and possibly bacterial feeding nematodes. When protozoa are eaten, this process also releases nutrients in plant available forms. And “the poop loop” continues.