In this article we will discuss about Vermicomposting:- 1. Meaning of Vermicomposting 2. Participating Organisms of the Vermicomposting 3. Physical Conditions.
Meaning of Vermicomposting:
Vermicomposting is a method by which compost or mixed manure of organic origin is prepared by the use of earthworms. It is a controlled degradation of the organic wastes for the consumption of earthworms, helps in the recycling of food wastes, reduces the waste bulk density and the final product may contain hormone-like substance which accelerates the plant growth.
Vermicomposting and vermiculture are two interlinked and interdependent processes, and vermiculture can be done in the presence of decomposable waste organic matter.
Participating Organisms of the Vermicomposting:
Bacteria, micro-organisms and earthworms participate in the vermicomposting process, of which bacteria and micro-organisms are used as food for worms.
Throughout the world, 3 or 4 species are used in vermiculture but two species are used extensively in India. Eisenia foetida and Eudrilus eugeniae are used throughout India for vermiculture. A list of some earthworm species is given below with some features which are used in different parts of the country.
Family Lumbricidae:
Eisenia foetida:
Distribution:
They are found throughout the country in muddy areas, sewage damps and tanks. The species is used in vermiculture throughout the world.
Features:
The colour of the body is red or brown or purple. The dorsal surface bears coloured bands often two per segment and the ventral surface is paler in colour.
The clitellum occurs over 7-9 segments which include 24, 25 or 26-32 body segments. The body weight is about 1.5 gm/matured worm. Maturity attains in about 50-55 days and during adult stage the body wall becomes ridged. The species is generally called red worm or tiger worm.
Bimastos parvus:
Distribution:
They occur in Kashmir, Himachal Pradesh, Punjab, Rajasthan and Uttar Pradesh
Features:
The body colour is brownish red. The clitellum is saddle-shaped and occurs over 6 or more segments which include 24 or 25-30. The body segments are usually 90.
Family Eudrilidae:
Eudrilus eugeniae:
Distribution:
Though the species was first recorded in South-West India but at present it is widely used in South India in vermiculture. The species was originally distributed in equatorial West Africa but recently it is found in most areas of the world. It is called ‘night crawler’ in U.S.A.
Features:
The colour of the body is brown or red dark violet. The clitellum occurs over 5-6 segments and include 13 or 14-18. Female gonopores are on the 14th segment and male gonopore, a few segments behind them.
The body segments usually range 145 to 196, and length of the body varies from 32 to 140 mm and diameter is about 5 to 8 mm. Maturity is attained within 40 days. The weight of the mature worms is about 4.3 mg per individual. The higher temperature tolerance is more higher than E. foetida.
Family Megascolecidae:
Lampito mauritii (Megascoles mauritii):
Distribution:
They are found in Punjab, South Rajasthan, Gujarat, Maharashtra, Madhya Pradesh, Andhra Pradesh, Tamil Nadu, Kerala, Lakshadweep Islands and Andaman Island.
Features:
The body colour is dark yellowish except the anterior end which bears purplish tinge. The clitellum is ring-shaped and spreads over 4 segments that include 14- 17 body segments. The length of the body ranges from 80-210 mm, with diameter 3.5 to 5 mm. The total body segments vary 166-190.
Metaphire anomala (= Pheretima anomala)
Distribution:
The species has recorded in Kokata (W. Bengal), Odisha, Bihar, Madhya Pradesh, Andhra Pradesh, Tamil Nadu, Karnataka and Kerala.
Features:
Total length of the body ranges from 80 to 90 mm, with diameter varies from 5 to 5.5 mm. The clitellum is ring-shaped which spreads over 3 body segments that include 13 to 16.
Pheretima posthuma:
Distribution:
It is the most common species in India and South-East Asia including Japan and Australia. They prefer to live the damp soil in the gardens and also in the dead organic matter.
Features:
Colouration of the dorsal side is brown and the ventral side is brightly coloured. The whole length of the full grown worm measures about 200 mm and 3 to 5 mm in diameter. The body segments about 100-120. The clitellum covers 3 segments on XIV to XVI. The use of the species in vermitechnology is not well studied.
Family Octochaetidae
Octochaetus surensis:
Distribution:
The species was recorded in Burkul and Sur Lake in Odisha, and has also been recorded across other parts of India.
Features:
Colouration of the body is greyish with dark tinge at the dorsal part of the anterior region. The total length of the body measures 75 mm and diameter is about 2 to 2.5 mm. The clitellum is ring-shaped and occurs over 5 segments which include 13th to 18th.
Dichogaster affinis:
Distribution:
The species is found in Gujarat, Maharastra and South India. Outside India it is recorded in Sri Lanka, East Africa, and Madagascar etc.
Features:
The colour of the body is pinkish brown. The worm measures 30-32 mm in length with diameter is about 1.2 to 1.5 mm. The total body bears 140 segments. The clitellum is saddle-shaped and 8-10 segments, namely 13th or 14th to 21th or 22th.
Dichogaster curgensis:
Distribution:
South India.
Features:
The colour of the body is greyish. The length of the body measures 65-75 mm and diameter is 2 mm. The whole body contains 90-110 segments. The clitellum is ring-shaped and contains 8 segments over 13th to 20th.
Oenerodrilus occidentalis:
Distribution:
They are found in Rajasthan, Maharashtra, Karnataka and Andaman Islands.
Features:
The total body length measures 15 to 30 mm and diameter is about 1 mm. The body segments are 70. The clitellum is ring-shaped and contains 6-8 segments, namely 13th or 14th to 19th or 20th.
Family Moniligastridae:
Moniligaster perrieri:
Distribution:
South India.
Features:
The body colour is generally blackish grey which is deeper on the dorsal side than the ventral side. The body length is about 210 mm and diameter is 5 mm. The total body segments are 175. The clitellum is ring-shaped and occurs over 5 segments from 9th to 14th segments.
Trophic Classification of Earthworms:
Based on the feeding habits, the earthworms are generally classified into detrivores and geophages. The detrivore earthworms feed mainly on plant litter, plan debris or mammalian dung. They collect the feed from the soil surface. These worms compose the epizeic forms.
The detrivorous earthworms are Eisenia foetida, Eudrilus eugeniae, Lampito mauritii, Polypheretima elongata, Octochaetona serrata, Octochaetona surensis, etc.
The geophagous earthworms live in underground burrows and eat large quanties of deeper organic rich soil which remains beneath the surface layer. These worms are called humus feeders. Pheretima posthuma and Octochaetona thurstoni are the examples of geophagous earthworms.
Process of Vermicomposting:
It deals with the various aspects like:
(i) Types of container,
(ii) Filling it with moist bedding
(iii) Introducing worms and
(iv) Feeding the worms on a regular basis.
These types of aspects for vermicomposting are practised in small scale vermicomposting but in larger scale the basic processes are same excepting the composting containers.
1. Composting container:
The shape or size of the containers depends upon the amount of waste to be composted and the number of earthworms which we want to culture
In 1m × 1m × 0.5 m high container 2000 adult earthworms can be maintained which can convert 200 kg wastes into composting material per month. In 2.23 sq. metre container 10 kg earthworms can be maintained which can convert about 1 ton waste per month. The selected container should be cleaned before use.
The followings are considered as composting materials which are being listed below:
(i) The animal dungs such as cattle dung, goat dung, sheep dung and poultry dropping are used as the composting material. The preliminary testing and precautions are necessary for the pathogens which can be harmful to earthworms excepting cowdung.
(ii) The agricultural waste materials which include the discarded part after harvesting and threshing of the paddy, wheat, etc. The vegetable wastes, leaf litter and sugarcane trash are considered as the composting material. The various kinds of forestry wastes, such as peels, saw dust are also considered. The leaf litters, such as mango, guava and grasses are used as composting materials.
(iii) The garbage includes various kinds of biodegradable and non-degradable materials. The biodegradable materials, such as kitchen vegetable waste, paper, should be sorted, recycled or composted.
2. Bedding material:
At the bottom of the containor, a 2-3 inches thick layer of biodegradable matter, e.g., husk, grasses, stem of crops and sugar cane trash, etc. which are used as the feed of earthworms, is laid. Next to this layer, another layer of 2″-3″ thick of powdered cowdung is put.
The whole material is maintained moistened and required number, of live earthworms are released. Above this a 7″-9″ thick layer of earthworm feed matter is put and watered. The whole material is covered with a moist gunny bag.
The earthworms would multiply by consuming the food and compost the matter from upper layers. The upper layer of vermicompost becomes ready within 60-70 days. Gradually the whole matter will be converted into vermicompost within 30-40 days with the bacterial decomposition.
Feed Materials of Earthworms:
Earthworms eat decomposed organic matters. So various kinds of food are prepared used in vermiculture.
A list of feeds is given below:
1. Old cow dung which is used after 7 days.
2. Cow dung is mixed with kitchen wastes in the ratio of 10:3.
3. Cow dung is mixed with agricultural wastes in the ratio of 10:3.
4. Cow dung is mixed with rice polish or wheat bran in the ratio of 10: 3.
5. Cow dung is mixed with sewage sludge in the ratio of 10: 3.
Only cow dung or mixed dung, such as goat dung, sheep dung or poultry dropping are used. Mixed dung is prepared in the ratio of 50: 50. Any of the above-mentioned mixed materials are mixed thoroughly. Heaps should be kept in shaddy places for 2-3 weeks and watered. Then the material is dried and beaten to make the material powdery which is used as feed for earthworms.
Required Physical Conditions for Vermicomposting:
During vermicomposting the following conditions, such as:
(i) Moisture content,
(ii) Oxygen,
(iii) Temperature and
(iv) pH of the substrate must be noticed for the vermiculture.
(i) Moisture content:
The moisture content must be maintained between 30-40%.
(ii) Oxygen.
(iii) Temperature:
For better results, the growth or multiplication of worms takes place between 20-30 °C.
(iv) pH of the substrate:
pH of the substrate would be between 6.8-7.5.