Getting To Know Earthworms

More than 2 000 species of earthworm have been identified worldwide and there are 300 known species in South Africa. The presence of earthworms is a good indication of soil health.

- Bill Kerr

South Africa is home to the African giant earthworm (Microchaetus rappi), the largest species in the world. Found in the Eastern Cape, it averages about 1,4m in length, although a gigantic specimen of 6,7m was discovered in 1967.

The castings formed by this species are so large that they look like old grave mounds; I have seen them myself when travelling in the region. A researcher compared samples of M. rappi castings with soil samples from the surrounding area and unsurprisingly found much higher levels of carbon and nitrogen in the mounds.

Types of earthworm

There are three groups of earthworms, namely epigeic, endogeic and anecic.

•  Epigeic Epigeic earthworms do not live in the soil but in surface organic matter. They are useful for converting waste organic matter into vermicompost.