A healthy population of earthworms is a good indicator of the right soil conditions for plant growth. Earthworms don’t like soils that are too acidic, alkaline, dry, wet, hot or cold. Plenty of earthworms in your soil means that your soil is in good condition.
Earthworms benefit the soil by increasing nutrient availability, improving drainage and creating a more stable soil structure.
Their extensive channeling loosens and aerates the soil up to 10x faster than in soils without them, helping to reduce the need for tillage.
Worm tunnelling helps to draw down applied fertiliser products into the soil. Worm casts are rich in nutrients including nitrogen and phosphate, with these nutrients being readily available to plants. In soils that are not tilled with high worm populations, water drainage and infiltration can be up to 6x higher than that of cultivated soils. Worm casts help to rebuild topsoil and in the right conditions can form a 10mm layer of topsoil annually.
Worms can lose 20% of their body weight each day in mucus and castings and need moisture to stay alive. A soil rich in humus holds moisture better, contributing to the continued cycle of life in the soil.
Research released by Schon, Gray and MacKay (2016) in the NZ Grassland publication found that a diverse earthworm population on sheep and beef farms increased pasture production by 5-45%, and the greatest impacts were seen from autumn to early spring. The average value of extra pasture grown equated to a 7-27% increase in grow margin per hectare.
A healthy worm population also acts as a natural soil probiotic (streptomycin) helping to reduce facial eczema and other inflammatory issues in livestock.
For more in-depth information search the internet for:
- The benefits of earthworms in agriculture
- How do earthworms influence soil health?