Vermiculture and Vermicomposting

Vermiculture is the cultivation of worms for agricultural purposes. The literal meaning of "vermiculture" is worm growing or worm farming. [1] When these cultivated worms are used for compost formation, it is termed as "vermicomposting".

Vermicomposting implies the use of various types of worms for formation of compost, so as to use it for agricultural purposes. The types of worms involved in the formation of compost include earthworms, white worms, wrigglers, etc. [2]

Vermiculture is a method of cultivating earthworms which focuses on increasing the worm biomass (the dry weight of an earthworm without any moisture content). [3] In other words, greater the quality of the earthworm cultivated, greater is the worm biomass.

The end product of the breakdown of organic waste by an earthworm is known as "vermicast". It is also known as worm castings, worm manure, and worm humus. [4]

Vermiculture - Types of Earthworms

Earthworms are also known as "friends of the farmer" as they decompose organic waste material present in the soil, and make the soil fertile for agricultural use. In other words, organic waste generated by different life forms is recycled by earthworms to form humus, thereby improving the quality of soil used for cultivation.

In the process of vermiculture, there are four types (ecotypes) of earthworms cultivated, depending on the feeding and burrowing habits - [5] [6]

Compost - These earthworms are found in a compost pit. These types of earthworms thrive in the presence of moisture, warm environmental conditions, and readily available compost material.

Compost material is consumed by these earthworms, and vermicompost is formed. These earthworms are striped and red in colour.

Epigeic - Epi = Top, Geic = Earth.

These earthworms live on the upper part of the soil. These are not burrowing earthworms, but survive 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 making permanent vertical burrows deep into the soil. Therefore, these earthworms live on the upper part of the soil, as well as in deep soil burrows. Castings of these earthworms are often seen in grasslands.

These earthworms are large in size, and dorsally pigmented. The head part is red or brown in colour, and the tail has a pale appearance as compared to the head part.

Endogeic - Endo = Inner, Geic = Earth.

These earthworms are completely burrowing. They create horizontal burrows, and feed on material present 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.

In vermiculture, the main species of earthworms cultivated are as follows - [7]

Applications of vermiculture

1. Alternative to fish feed -

Worm castings obtained from vermicast can be used as an alternative to fish feed. Vermicast is an extremely high source of protein and other nutrients.

Trout fed with frozen extracts of earthworm species such as Elsenia fetida, Allolobophora longa, and Lumbricus terrestris showed greater growth as compared to trout which were fed with commercial fish protein. [8]

However, care should be taken that excessive vermicast should not be used as fish feed as the presence of excessive vermicast used as fish feed can have an adverse impact on the pH of the water.

2. Improvement in land quality -

Industrialization, mining, increased usage of chemical fertilizers, pesticides, and urbanization are responsible for soil pollution and depletion in land quality. These activities are responsible for the removal of the topsoil, rendering the land unfit for cultivation.

To improve land and soil quality under such circumstances, a novel technique has been developed known as Earthworm Inoculation Unit (EIU) technique.

EIU technique has two phases -

Cultivation - Starter earthworm cultures are cultivated using soil, earthworms, and feed.

Soil inoculation - Cultivated starter cultures are inoculated into the soil. These cultures migrate into the soil in a radial manner from the point of inoculation. Complete migration into the soil depends upon factors such as soil quality, moisture content of soil, availability of organic matter, etc.

The survivorship of these starter cultures in the soil is analyzed for a period of ten months after soil inoculation. Those starter cultures which are able to survive in the soil in extreme conditions of temperature and moisture, reproduce rapidly, and able to migrate into the soil far away from the point of inoculation to the maximum possible extent are then selected for the purposes of soil remediation and improving land quality. [9]

3. Production of therapeutics in human health care -

Anticoagulants - Anticoagulants are administered to those individuals suffering from internal blood clots which clog and block blood vessels. It has been found that earthworm extracts isolated from vermicast and cultivated earthworms possess the property to prevent clotting of blood. Earthworm extract (G-90) has been found to have a fibrinolytic and anticoagulative effect on blood. [11]

Antioxidants - Fluids extracted from an earthworm such as coelemic fluid, earthworm paste, earthworm extracts have been found to possess antioxidant activity in in-vitro conditions as determined by the use of various tests such as DPPH scavenging method, Folin-Ciocalteau method, etc.

The antioxidant activity of earthworm extracts can be explained by the fact that extracts from earthworm possess the capacity to donate electrons to reactive species such as free radicals, which stabilizes them. This method of stabilization of reactive free radicals is speculated to be responsible for the antioxidant activity of earthworms. [10]
Current Research

Current Research

• Lumbrokinase is an enzyme isolated from the earthworm Lumbricus rubellus. This enzyme is believed to prevent the occurrence of blood clots, strokes, and cardiovascular disorders, as well as enhance heart health. Lumbrokinase has been processed so as to be consumed in the purified supplemental form. [12]

However, it is to be noted that the enzyme Lumbrokinase isolated from earthworms has not yet been approved by the Food and Drug Administration (FDA) as therapy for treating strokes and cardiovascular disorders.

By - Larry Hall



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