What is wrong with that statement is that the soils lack the nutrients. That is incorrect. The nutrients are there, they are just not plant available. And this is where the soil organisms come into play.
The trophic layers of the soil food web
First let’s explore the different levels of the soil food web.
Level 1 – Photosynthesizers – plants that convert the sun and CO2 into sugars that feed the soil life
Level 2 – Bacteria, fungi, root feeding nematodes. Decomposers, Mutualists, Pathogens, Parasites, Root Feeders (bad nematodes)
Level 3 – Bacteria and fungal feeding nematodes, protozoa, arthropods. Shredders, predators, grazers (this is where nutrients become plant available)
Level 4 – Larger arthropods, predatory nematodes . Higher level predators
Level 5 – Birds, small animals. Even higher level predators.
When a higher trophic layer organism eats something from a lower level, that is when you nutrients for your plants are released!