Question

Which one of the following species of an earthworm is not recommended for vermicomposting?
(a)Perionyx excavatus
(b)Pheretima posthuma
(c)Eudrilus eugeneae
(d)Eisenia foetidae

Answer 1

Hint: All earthworms are not involved in the vermicompost process. As humus formers and humus feeders, earthworms are categorized. Though humus feeders are not good for vermicompost, humus formers are good for vermicompost. In New Guinea and parts of Southeast Asia, this organism is mostly found.

Complete answer:
As it is a humus feeder, Pheretima posthuma is not recommended for vermicomposting. Pheretima posthuma is unable to turn the waste into a nutrient-rich compound called humus. So, for vermicomposting, it is not considered appropriate.
The humus formers are focused on the surface and feed on almost 90% organic materials. They are normally darker in color, often referred to as epigeic or detritivorous earthworms.
It is these worms normally harnessed for vermicomposting. The humus feeders are burrowing worms, some of which are helpful in preparing both compost and making the soil porous. The burrowers usually assist in the mixing and distribution of humus through the soil.
Like most earthworms, Pheretima is usually nocturnal, and has an aversion to light. They come out at night only, and eat and reproduce at night only. They must keep the surface of their body moist to breathe, similar to other earthworms. As they assist in keeping the soil porous for fast irrigation, they are often called farmer's friends.

Additional Information: Humus formers are good for vermicompost among the earthworms and they include Eudrilus eugenics, Eisenia foetidae, and Perionyx excavators.
Humus provides plant nutrients and improves the water retaining potential of the soil. When dead plant and animal matter decays, humus is the dark organic matter that occurs in the soil.
So, the correct answer is, ‘Pheretima posthuma’.

Note: Vermicompost (vermicompost) is the result of the decomposition process to produce a mixture of decomposing vegetable or food waste, bedding materials, and vermicast using different species of worms, usually red wigglers, white worms, and other earthworms. This method is called vermicomposting, while vermiculture is called the rearing of worms for this reason.