Soil-borne plant pathogens are controlled or suppressed. We explain how most of these results are obtained using the earthworm as an example. Earthworms migrate to and inhabit healthy soil, then help to maintain that health. To increase your earthworm population, feed them organic foods and composted manures, avoid over tilling, mulch all bare soil and avoid high nitrogen fertilizers and chemical pesticides. Earthworms will repopulate naturally if they aren't poisoned.
Earthworms tunnel through the earth, excreting polysaccharides.
Polysaccharides are sugars that act like glue to line the pencil-size tunnels, preserving them for years. As they move through the earth both horizontally and vertically earthworms drag bits of organic material around, helping to mix organic matter into the soil. As they eat the organic material, they turn it into rich nutrients by leaving castings everywhere they go. There are also compartments within the worm's body in which microorganisms multiply and are then released into the soil. They break up soil hardpans and compacted soil.