This means developing an understanding of how different farm practices influence their numbers and using those practices that tend to encourage earthworms to proliferate. Before you begin changing your farm practices to accommodate worms, it is useful to know the different kinds of worms and how they work. The earth is home to many thousand of earthworm species, but only about a dozen or so seem to be important for agricultural soils. Each fall into one of three basic categories, defined by where it lives, what it looks like, and the unique roll it plays in the soil ecosystem. Endogeic earthworms are the workhorses of most California soils.
Epigeic earthworms live close to the surface, where organic matter is concentrated.
These include the red worms that are readily purchased from commercial earthworm dealers. It s not practical to add this kind of earthworm directly too most farm soils and expect a big increase in the populations, because they need an abundant and regular supply of surface organic to thrive. However, they can be very useful for transforming organic wastes into high-quality fertilizer, a process call vericulture. The third type, the anecic species, are heroic creatures exemplified by the nightcrawler. These are large, muscular species that create deep, vertical burrows that become their permanent residence over a life span that may last one to ten years.