Vermicomposting

About two thousand five hundred species of earthworms have been identified in the world of which more than five hundred species of earthworms have been identified in India. Diversity of earthworm species varies with different types of soils and hence choosing a local or native species of earthworm for the local soil and for vermicomposting is an important step. There is no need to import earthworms from elsewhere. Local species of earthworms that are generally used in India are Perionyx excavatus and Lampito mauritii. These earthworms can be cultured or used in composting applying simple procedures either in pits, crates, tanks, concrete rings or any containers.

• Vermibed (vermes= earthworms; bed= bedding) is the actual layer of good moist loamy soil placed at the bottom, about 15 to 20 cm thick above a thin layer (5 cm) of broken bricks and coarse sand.
• Earthworms are introduced into the loamy soil, which the worms will inhabit as their home. 150 earthworms may be introduced into a compost pit of about 2m x 1m x 0.75m, with a vermibed of about 15 to 20 cm thick.
• Handful‑lumps of fresh cattle dung are then placed at random over the vermibed. The compost pit is then layered to about 5 cm with dry leaves or preferably chopped hay/straw or agricultural waste biomass. For the next 30 days the pit is kept moist by watering it whenever necessary.
• The bed should neither be dry or soggy. The pit may then be covered with coconut or Palmyra leaves or an old jute (gunny) bag to discourage birds.
• Plastic sheets on the bed are to be avoided as they trap heat. After the first 30 days, wet organic waste of animal and/or plant origin from the kitchen or hotel or hostel or farm that has been pre-digested is spread over it to a thickness of about 5 cm. This can be repeated twice a week.
• All these organic wastes can be turned over or mixed periodically with a pickaxe or a spade.
• Regular watering should be done to keep the right amount of moisture in the pits. If the weather is very dry it should be dampened periodically.

1. The compost is ready when the material is moderately loose and crumbly and the colour of the compost is dark brown. It will be black, granular, lightweight and humus-rich.
2. In 60 to 90 days (depends up on the size of the pits) the compost should be ready as indicated by the presence of earthworm castings (vermicompost) on the top of the bed. Vermicompost can now be harvested from the bin/pit.
3. To facilitate separating the worms from the compost, stop watering two to three days before emptying the beds. This will force about 80 per cent of the worms to the bottom of the bed.
4. The worms can also be separated by using sieves/meshes. The earthworms and the thicker material, which remains on top of the sieve, goes back in the bin and the process starts again. The smell of the compost is earth-like. Any bad odour if formed is a sign that fermentation has not reached its final goal and that the bacterial processes are still going on. A musty smell indicates the presence of mold or overheating which leads to loss of nitrogen. If this happens, aerate the heap better or start again, adding more fibrous material and keeping the heap drier. The compost is then sieved before being packed.
5. The harvested material should be placed in a heap in the sun so that most of the worms move down to the cool base of the heap.
6. In the two or four pit system, watering should be stopped in the first chamber so that worms will automatically move to another chamber where the required environment for the worms are maintained in a cyclic manner and harvesting can be done continuously in cycles.

• Organic wastes can be broken down and fragmented rapidly by earthworms, resulting in a stable nontoxic material with good structure, which has a potentially high economic value and also act as soil conditioner for plant growth.
• Vermicompost supplies a suitable mineral balance, improves nutrient availability and could act as complex-fertilizer granules.
• Vermicomposting involves great reduction in populations of pathogenic microorganisms, thus not differing from composting from this point of view.
• Vermicomposting also leads to decrease the environmental problems arising from their disposal, without needing in many cases to complete the process.
• It should be realized that vermicomposting can be a useful cottage industry for the underprivileged and the economically weak as it can provide them with a supplementary income.
• If every village can formulate a cooperative society of unemployed youth/women group, it could be a wise venture for them to produce vermicompost and sell it back to the village at a recommended price. The youth will not only earn money, but also aid society by providing excellent quality organic manure for sustainable agro-practices.