believed to play a crucial role in cast-associated processes (CAPs), which take place
during the ageing of the vermicompost, following transit of the organic materials
through the earthworms’ gut.
Starting Mixture
[Optimized mixture of organic materials]
Microbes
[Effective micro-organisms
(EM), Phosphate solubilizing
microbes (PSM), Nitrogen
fixing bacteria, etc.]
Earthworms
[E. fetida, E. Andrei,
Perionyx excavates etc]
Cast Associated
Processes (CAPS)
-Increased humification.
-Release of inorganically bound
nutrients through action of
organic acids.
-Toxic metal immobilization
(organic matter and mineral
bound).
Gut Associated Processes (GAPs)
-Increase in substrate surface area through
fragmentation, homogenization.
-Increase in biochemical activity (enzymes).
-Modification of microbe and macro-fauna profiles.
-Reduction of total coliforms
- Reduction in C/N ratio through organic matter
degradation
-Release of metallothionein for heavy metal
detoxification.
Vermicompost
Well stabilized compost rich in bioavailable nutrients (N, P, K and trace elements)
and reduced heavy metal bioavailability.
Fig. 18.2 Schematic representation of earthworm and microbe roles during vermicomposting of
organic materials. (Source: Mupambwa and Mnkeni 2018)
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