Vermiculture


Vermiculture means worm farming or culturing worms for selling them either to fishermen or to compost manufacturers. When earthworms are used for the production of compost it is called vermicomposting. Earthworms burrow through the soil and feed on decaying organic matter, excreting castings that are rich in nutrients and beneficial micro-organisms, which are about 20 times more in worm castings than in normal soil. These beneficial organisms not only make available nutrients to the plants but also suppress the growth of pathogens leading to healthy plants.

The most common worms used in vermiculture are, red worms (Eisenia foetida, Eisenia andrei, and Lumbricus rubellus). These worms thrive at temperatures between 20-30°C and can be cultured indoor in boxes. Other worms like Perionyx excavatus and Eudrillius eugieneare are suitable for warmer climates.

Vermiculture Medium

Crop residues, dry leaves, cattle dung are the basic materials for culturing earthworms, along with saw dust, coir waste, paddy husk, slurry from biogas plant, poultry waste and vegetable wastes. Earth worm culturing should be done under shelter to avoid direct sunlight and flooding by heavy rain.

Containers for Vermiculture

Brick lined pits, plastic tubs, wooden boxes, earthen pots or any other suitable containers can be used for culturing earthworms. The ideal size is 1 m x 1 m x 0.3 m but dimensions can be changed to suit the amount of waste material and convenience but the depth of pit should not be more than 45 cms. Sometimes a heap of organic matter over plain ground in shady area can also be used for culturing.

METHOD OF CULTURING EARTHWORMS

1)  Select a container or dig a pit of suitable dimensions in shady areas.

2)  At the bottom of the pit or container, make a wormibed of 10 cm height using coir waste, paddy husk, sugar cane trash, old papers etc. and spread a layer of soil over it. Wet the bed by sprinkling sufficient water over it to obtain a relative humidity of 40-45%.

3) Mix the organic waste, cattle dung and slurry from biogas plant or any other organic material and spread it over the bed. Keep this mixture for two weeks for half digestion, during which heating of substrate will take place and temperature will rise to 50-55°C. Add 5-10 % of neem cake in this material. Neem cake has beneficial effect on the growth of worms and kills harmful microorganisms.

4)  Once the organic feeding material has cooled down to about 30°C, introduce worms by spreading them over the bed at the rate of 500 worms for every 100 kg of organic material.

5)  Cover the bed with jute cloth, straw or similar material to provide shade and protection to the worms. Water has to be sprinkled over this cover to maintain the moisture content at 45-50% and temperature between 20-30°C. The pH of the raw material should not exceed 6.5-7.

The worms feed actively on organic matter and excrete mounds of castings near the surface. In about 60 days the compost will be ready.

6)  To separate the worms from compost, take out the vermicompost and spread it in a heap in sunlight on a plastic sheet. In about two hours all the worms will move to the bottom of the heap. The compost can be removed from the top and used in fields, and the worms from the bottom can be carefully collected and used for further vermicomposting.

VERMICOMPOSTING TECHNIQUE FOR FARMERS

  • The vermicomposting is done by digging pits 3.0 m long, 1.0 m wide and 1.0 m deep
  • At the bottom of the pits, broken pieces of earthen pots or bricks are spread to provide adequate drainage.
  • Over the layer of bricks, a bed of paddy husk or dry leaves is spread and then a layer of 2.5 cm thick soil is spread over it. 
  • Cattle dung and other organic wastes are then spread over the bed in about three inches thick layer.
  • This organic material is allowed half digestion for about two weeks when temperature will increase to about 50°C.
  • Worms can be introduced after this incubation period is over and when the temperature has come down to about 30°C. About 500 earthworms are then introduced into the pit, and a layer of paddy straw is placed over them. Water should be sprinkled and the pit is covered with coconut fibres or paddy straw or dry leaves to protect the worms from sunlight and predators.
  • Fresh layers of organic waste can be added over this material every 3 or 4 days and covered with a layer of soil and paddy husk.
  • The earthworms will move to the upper layer after finishing food material in the lower layers.
  • The pit can be charged with all kinds of organic wastes in layers of about 5 cm, covered with a layer of soil till the material reaches the top of the pit.
  • When the pit is full, it should be covered with husk and a layer of soil, and left for 30-60 days, during which compost will be fully formed.
  • To procure the compost, top layer should be exposed to sunlight to force the earthworms to move to the deeper layers, so that compost could be removed from the top.
  •  The worms collected at the base can be used for inoculating new vermicomposting pits.
  • The quality of vermicompost is far superior to other composts in terms of nutrients and other plant growth promoting substances.

Vermicompost production using worms such as Eisenia foetida, Lumbricus rubellus and Eudrilus eugeniae can be enhanced by using cattle urine for moistening organic wastes during the preliminary composting stage before the addition of worms. This simple technique can yield vermicompost of a higher Nitrogen content. Moreover, worms have been found to become more active and vermicompost can be harvested at least 10 days earlier if cattle urine is used.