Verniculture | Zoology Optional Notes for UPSC PDF Download

What is Vermiculture?

As the name suggests, vermiculture is the artificial rearing of certain earthworm species that play an active role in decomposing food waste into nutrient-rich substances (manure). These earthworms have the ability to consume the decomposing organic material and flush it out of their system as a nutrient-rich compound referred to as worm manure.

Purpose of Vermiculture

• You might wonder why we need worms when decomposition can be still carried out in their absence by soil microorganisms? Here is your answer.
  Earthworms feed on waste organic matter and break them into smaller compounds. This facilitates faster decomposition by allowing microorganisms to easily break down these organic matters and produce nutrients.
• Nutrients produced by soil microorganisms makes the soil more fertile for the plant. Vermiculture requires around 1000−12001000−1200 earthworms to break down approximately 1kg1kg of organic matter. Earthworms help farmers in several ways like they dig or mix soil making it more aerated and moist, water holding capacity of soil is also increased by their activity and lastly various plant nutrients are released by their intestine all together aids to the formation of nutrient-rich humid soil that promotes plant growth. This is why earthworms are called farmer’s friends. Farmers can add more inorganic matter to the soil to encourage earthworms.

What are the Requirements for Vermiculture?

Vermiculture was first begun in around 19701970 by a biology professor, Mary Appelhif, who explained the idea of using red wiggler worms for composting in indoor and outdoor systems to convert kitchen garbage to worm compost. Earthworms and raw organic materials are the two main requirements of the vermiculture process. Let’s discuss these in a little more detail.

• Organic Materials: Organic material is the food of the earthworms. Thus, it is the basic requirement for the process of vermiculture to begin. These organic materials can be food waste, animal waste, agricultural waste (agro-waste), or plant waste. The raw mixture used for vermiculture must possess the following properties:
  a. It should contain 75%75% of moisture.
  b. It should be free of pesticides, chemical and tannins residues.
  c. Density needs to be below 640lb/ft3.640lb/ft3.
• Earthworms: Eisenia fetida, also known as red wiggler, is the most common earthworm used for vermiculture all over the world. This is due to their high metabolic rate. They can convert the organic matter into vermicompost within 45−5045−50 days.

Types of Earthworms for Vermiculture

Earthworms play an essential role in decomposing organic waste material present in the soil and making it fertile for agricultural use. In other words, earthworms recycle organic waste generated by different life forms to form humus, thereby improving the quality of soil used for cultivation. There are four types (ecotypes) of earthworms cultivated in the process of vermiculture based on the feeding and burrowing habits –

• Epigeic (Epi = Top, Geic = Earth): These earthworms live on the uppermost part of the soil. These are not burrowing earthworms but remain by feeding on soil litter. These earthworms are small in size. They are not striped and are red to red-brown in colour.
• Anecic: These earthworms feed on soil litter by creating permanent vertical deep burrows in the soil. Therefore, these earthworms live on the upper part of the soil as well as deep soil burrows. Castings of these earthworms are often seen in grasslands. These earthworms are giant and dorsally pigmented. The head part is red or brown, and the tail has a pale appearance compared to the head part.
• Endogeic (Endo = Inner, Geic = Earth): These earthworms are completely burrowing. They build horizontal burrows and feed on matters found deep within the soil surface. These earthworms are rich soil feeders and are small in size. These earthworms are not pigmented but have a pale appearance.
• Compost: These earthworms are found in a compost pit. These earthworms thrive in the presence of moisture, warm environmental conditions, and readily available compost material. These earthworms consume compost material, and vermicompost is formed. These earthworms are striped and red.

Mechanism of Digestion in Earthworms

The digestion of earthworms plays an important role in vermiculture. Hence, here is a glimpse of this process for you.

• The process of consuming food in worms is done by the buccal cavity that emerges during feeding, with the help of protractile and retractile muscle. The food is consumed in the pharynx.
• The pharyngeal gland contains a chromophil cell, where the saliva is produced. Saliva contains mucin, which softens food, and protease, which converts protein into amino acids.
• The next region where the food is passed is known as the gizzard (oesophagus). Here, the food particles are converted into fine substances by the contractions of the gizzard muscle.
• Many intestinal enzymes like protease, amylase, cellulase, chitinase, lipase help in the digestion process for breaking down various nutrients.
• Their discharged material is called worm casting or vermicast. It is rich in numerous minerals that can be easily used by plants.

Process of Vermicomposting

Earthworms are cultured for the purpose of vermicomposting. The process of vermicomposting involves the collection of earthworms, construction of compost pit or bed, harvesting of compost, packaging, and marketing. Below is the diagrammatic explanation of this process.

• Collection of Earthworms: Multiplication of earthworms is an important step in the vermiculture process. It can be easily done by the farmers using the steps given below:
  • One should add different types of biodegradable wastes that we discussed under the previous topic.
  • Around 4040 or more species of earthworms are added into the mixture after properly mixing all substances.
  • The mixture needs to be guarded against heat, rain and environmental factors by a regular maintenance check.
  • The temperature and moisture level have to be maintained throughout the period.
  • Earthworms multiply 300300 times within two months when well maintained.
• Construction of a Vermicomposting Unit: Once the earthworms are ready to turn normal soil into a treasure of nutrients, the process of vermicomposting is carried further. Following are the steps involved in the process:
  • Construction of a vermicomposting unit like a compost pit or a vermibed is the first step of the process.
  • In this step, various wastes are layered one above another along with earthworms. The pit is protected by covering it with either coconut leaves or old gunny bags.
  • The substances are turned upside down after an interval of certain days to facilitate decomposition.
  • The worm liquid present at the bottom of the compost pit is called worm tea. It is of great help in the growth of garden plants.
• Harvesting of Vermicompost:
  a. Production of worm casting is the sign that vermicompost is ready for harvesting.
  b. At this stage, worms are isolated from the solid waste by using light treatment or using sieves or meshes.
• Packaging, Transport and Marketing:
  a. The isolated product is packed in laminated over sacs to avoid loss of moisture content and label it with details like the brand’s name, nutritive facts, direction to use, price, etc., and transported to farms, gardens, plant nurseries, green house plants, etc.

Advantages and Disadvantages of Vermiculture

Advantages of Vermicompost

• Vermicompost is the best replacement for chemical fertilizers.
• Vermicompost is eco-friendly as it is produced by organic waste through vermiculture.
• Vermicompost is also a natural fertilizer.
• Water holding capacity increases due to the organic substances used in vermicompost.
• Improves plants growth and nutrients absorbing capacity.
• Vermicompost contains antibiotic properties that help to regulate compost.
• Crop yields and seed germination also improves.

Disadvantages of Vermicompost

• Vermicomposting takes a long period of time of 6 months.
• There is a little odour present in it.
• The maintenance is high as it has to be kept under maintenance for a long period of time.
• If not taken care of, there are chances of pathogens and pest problems.
• Time-consuming process.

Application of Vermiculture

Vermiculture has many applications for different purposes in various industries. Some of these are mentioned below:

• Land quality improvement: Continuous usage of pesticides or chemical fertilizers and urbanization have caused long term soil pollution and poor land quality leading to loss of topsoil, which makes the land unfit for cultivation. Earthworm inoculation unit (EIU) is a technique discovered to improve the quality of land and soil. The EIU uses two steps to achieve its goals:
  • Cultivation: Here, earthworm cultures (starter culture) are produced by mixing up soil, earthworms and feed (organic wastes).
  • Soil inoculation: Starter cultures are added into the soil, where radial migration of these cultures take place. Migration depends on factors like soil quality, moisture content and organic matter availability, etc. The starter cultures are observed for ten months for their best results, and the cultures which succeed in surviving into the soil are selected for the EIU technique to improve the land quality.
• Fish feed alternative: Vermicast produces worm casting, which is used as the fish feed alternative. An excess amount of vermicast may have a bad impact on the pH of water. Hence proper care needs to be taken while adding it as an alternative feed.
• Human health care: These are also used to make certain remedial products. Two such examples are:
  • Anticoagulants: These help people who are suffering from internal blood clots blocking blood vessels. Earthworm extracts derived from vermicast and cultivated earthworms are known to have the property to prevent blood clotting.
  • Antioxidants: Coelomic fluid, earthworm paste, earthworm extracts, etc. Certain fluids extracted from earthworms are known to have antioxidant activity in in-vitro conditions. The antioxidant activity can be explained by the fact that earthworm extracts bear the capacity to donate electrons to reactive species such as free radicals, which stabilizes them. This process of stabilization of reactive free radicals is considered to be responsible for the antioxidant activity of earthworms.

Summary

Vermiculture is the scientific process of artificial rearing or cultivation of Earthworms for the improvement of human beings. Vermicompost is the excreta of earthworm that is a rich source of humus. Earthworms feed on cow dung or other farm wastes and pass it through their body converting it into vermicompost. The municipal wastes, toxin-free solid or liquid waste of the industries and household trash can also be converted into vermicompost with this technique. Earthworms not only convert waste into valuable manure but also keep the environment healthy. Conversion of garbage by earthworms into compost and the multiplication of earthworms are simple processes that can be easily handled by farmers.