EARTHWORM AS SOIL ECOSYSTEM ENGINEERS: A REVIEW

Earthworm and microorganisms are interdependent on each other. The interactions between them help to regulate the biogeochemical cycle of terrestrial life. A large diversity of fungi, bacteria, yeast, actinomycetes and protozoa are found to be present in the gut and cast of earthworms. Their number and species depend on their feed substrates obtained in soil. It has been studied that the microbial proliferation is more in the casts, due to the environment prevailing-rich nutrient supply and large surface area available for growth and reproduction of the microbes that lead to the enhanced microbial activity and humic acid contents in casts. Diversity of microorganisms is also found in vermicompost and vermiwash. This in turn depended on the raw material used for compost. A significant increase was noted in flora after composting. Within an ecological group, habitat was found to be a more important determinant of the gut wall associated community composition than the host species.