Earthworms in the wild
In terms of biomass and overall activity, earthworms dominate the world of soil invertebrates, including arthropods. They play a major role in the soil structure as they induce soil movement, nutrient flow, water movement, and plant growth. While not essential to soil health, they are a proven indicatorsf healthy soils (Labenz, 2014).
Waste reduction and soil amendment
Earthworms are waste managers as they break down organic materials. They are not only composting these materials, but they also provide good quality and sanitized soil amendment (vermicompost) and supplemental protein source (the earthworms) to feed farm animals and aquaculture species (Edwards et al., 2011; Sinha et al., 2010; Eastmann et al., 2001; Eastmann, 1999). Vermicomposting with the help of earthworms in a viable method for turning organic wastes into a viable supplemental protein source, while enhancing soil characteristics. Thanks to waste digestion by earthworms, the vermicompost is free of pathogens and as safe as conventional compost without the need of high temperature (Sinha et al., 2010; Eastmann et al., 2001; Eastmann, 1999).
Nutrient leaching prevention
Thanks to its high humic matter and physical structure, vermicompost has a high water capacity retention and prevents nutrients from being lixiviated with water in the soil (Munroe, 2008).
Pasture fertility enhancement and soil sanitization
Earthworms used for vermicomposting are epigeic species. They do not survive for long in the soil as it is not loose enough to be colonized. The cocoons contained in the vermicompost are quite resistant to soil conditions and can survive and develop in pasture stands provided they receive fresh faeces from grazing livestock. They are able to transform animal faeces into valuable castings and enhance the fertility status of the stand . It has been reported that the earthworms that develop from the cocoons are able to destroy the pathogens that could be brought in the faeces, which has a sanitization effect on the soil and on the water that passes through the soil (Appelhof, 2003 cited by Munroe, 2008).