Interpretation
The more earthworms, the better. They indicate a high level of soil biology. There is no ‘ideal number’, but the presence of different categories and functions of earthworms suggest that your soil has a good level of soil life.
Soils should have a good diversity of earthworm species with a combination of the 3 ecological categories present:
- surface feeders that live at or near the surface to breakdown plant residues and dung (epigeic earthworm)
- topsoil-dwelling species that burrow, ingest and mix the top 200–300 mm of soil (endogeic earthworms)
- deep-burrowing species that pull down and mix plant litter and organic matter at depth (anecic earthworms)
Why are earthworms important?
- Their burrowing aerates the soil and improves soil structure.
- They breakdown organic matter for micro-organisms which in turn promotes humus production.
- They mix organic matter into soils.
- They turn and mix the soil as they pass through it.
- They promote the presence of positive bacteria and fungi in soils.