The soil food chain starts with plants and the plants the roots which supply energy from photosynthesis to the microorganisms that are useful for the plants.
It is bacteria, fungi, and nematodes that are eaten by arthropods, bacteria and fungi that eat nematodes, and protozoa and thereby release nutrients to the plants.
Predatory arthropods and predatory nematodes complete the microbiological part of the food chain which continues with the visible earthworms, snails, beneficial insects, birds, and moles.
In English, the method is called SOIL FOOD WEB, it is a method where only biology and regenerative methods are used for growing crops. Re-establishment of the soil biology is done by adding the biology to the soil and the crops, it takes 1 to 3 years to regenerate the soil microbiology. The method fights diseases, pests and reduce the need for fertilizer. It is all about re-establishing the biological cycle of nature.