Vermiculture

Vermiculture is the cultivation of earthworms for the purpose of composting organic waste into nutrient-rich fertilizer. It involves the use of specific worm species, such as Eisenia fetida (red wigglers) and Lumbricus rubellus, to break down organic material and produce vermicompost, a highly valuable soil conditioner.

1.0Introduction of Vermiculture 

• Vermiculture is the scientific practice of breeding and nurturing earthworms under controlled conditions.  
• Vermitechnology integrates both vermiculture and vermicomposting, utilizing earthworms to enhance soil fertility, decompose organic matter, improve aeration and drainage, and contribute to sustainable agriculture. Additionally, earthworms play a crucial role in producing valuable byproducts such as vermifertilizer and worm biomass, which can be used as animal feed.

2.0Earthworms

• Earthworms are popularly known as the "farmer's friend" or "nature's ploughman".
• Earthworms belong to: 
• Phylum - Annelida 
• Class – Chaetopoda 
• Order - Oligochaeta 
• They are the first multicellular eucoelomate invertebrates to have succeeded in inhabiting the terrestrial environment. 
• They are hermaphrodites; male and female reproductive organs are present in every earthworm, but self-fertilization does not generally occur.

3.0Anatomical Characteristics of Earthworms 

• Bilateral Symmetry: An earthworm exhibits bilateral symmetry, meaning that if it is cut along its central axis, the left and right sides appear identical.
• Locomotion: Earthworms move by contracting and relaxing circular and longitudinal muscles beneath their epidermis. Except for the first and last segments, each body segment contains eight tiny bristle-like structures called setae. These setae protrude from the skin, helping the worm anchor itself and propel forward as it crawls.
• Soil Interaction: While burrowing, earthworms secrete mucus, which binds with the surrounding soil. This interaction strengthens the tunnel walls, preventing collapse and maintaining structural stability.
• Respiration: Earthworms lack a specialized respiratory system. Instead, gas exchange occurs through their moist skin, where oxygen is absorbed into capillaries and transported via haemoglobin dissolved in blood plasma, while carbon dioxide is expelled.
• Circulatory System: Earthworms have a closed circulatory system, with a large blood vessel running along the body next to the gut. Two to five pairs of muscular blood vessels act as hearts, pumping blood through the system.  
• Brain and Nervous System: The earthworm’s brain consists of a fused pair of nerve ganglia, primarily located in the third segment. Nerve fibers extend along the body, encircling the gut and controlling movement and responses.  
• Reproductive System: The clitellum, a noticeable swelling on the skin, becomes visible only when the earthworm is ready to reproduce. 
• Depending on the species, it may appear white, orange-red, or reddish-brown. When the clitellum turns orange, the earthworm is mature and prepared for mating. 
• It also secretes materials essential for forming protective cocoons for developing embryos.

• During egg-laying, the clitellum develops into a hardened, girdle-like structure known as a cocoon. 
• Earthworms shed between one and five cocoons, though only a few successfully hatch. Cocoon formation typically takes around 50 to 60 days. The lifespan of earthworms varies by species, generally ranging from 1 to 10 years.
• Earthworms are long, narrow, cylindrical, and segmented. They have a glistening dark brown body covered with delicate cuticles. 
• The gut of earthworms is a straight tube starting from the mouth followed by a muscular pharynx, oesophagus, thin-walled crop, muscular gizzard, foregut, midgut, hindgut, associated digestive glands and ending with anus.

4.0Vermicompost Preparation

• Basic raw materials: Any organic material generated on the farm like wheat/rice straw, leaf fall, Paddy husk, etc. 
• Starter: Cow dung, Biogas slurry, or urine of cattle. 
• Earthworm sp.: Earth worms (Species: Eisenia foetida) 
• Thatched roof/vermin shed.

Favourable conditions of earth worms in the composting material 

• pH Level: Ideally between 6.5 and 7.5 for optimal growth.  
• Moisture: Maintained at 60-70%; levels outside this range can lead to worm mortality.  
• Aeration: Requires 50% of the total pore space to ensure proper oxygen flow.  
• Temperature:  Should be kept between 18°C and 35°C for healthy worm activity.

Procedure

• Vermicompost is primarily prepared using either the pit method or the heap method. The standard dimensions for both methods are 10 x 4 x 2 feet. While the length and width can be adjusted based on material availability, the depth must remain 2 feet, as earthworm activity is confined to this depth.  

Site Selection

• Choose an unused, shaded area with no water stagnation.  
• The site should be close to a water source for easy moisture management.  

Layering Process  

• 1.Bedding Layer (1 inch):  Soft leaves to create a suitable base for earthworms.  
• 2.Organic Residue Layer (9 inches):  Finely chopped plant material for decomposition.  
• 3.Dung-Water Layer (2 inches):  A mixture of dung and water to enhance microbial activity.  
• For the pit method, layers continue until they reach ground level. In the heap or surface bed method, layering is done up to 2 feet in height.  

Worm Introduction and Maintenance

• On the 24th day, approximately 4,000 earthworms are introduced per square meter (1m² = 2,000 worms).  
• Regular watering is essential to maintain moisture without disturbing the pit.  
• Earthworms must be protected from predators such as ants, lizards, snakes, frogs, and toads.  
• Proper aeration and moisture balance are maintained through periodic turning and stacking.  

5.0Compost Yield and In-Situ Vermicomposting

• The compost turnover rate is 75%, meaning if 1,000 kg of raw material is added, the final output will be 750 kg of vermicompost.  
• In-situ vermicomposting (direct field application) involves:  
• Applying 5 tons per hectare of vermicompost.  
• Spreading a 2.5 cm thick layer of cow dung.  
• Adding a 15 cm thick layer of farm waste.  
•  Irrigating every 15 days to maintain optimal conditions.  
• This process ensures efficient decomposition and promotes soil fertility, making vermicomposting a sustainable and eco-friendly farming practice.

6.0Precautions in Vermicompost

• Avoid covering beds with plastic sheets, as this can trap heat and gases, negatively impacting earthworm activity.  
• Do not overload the compost heap , as excessive material can raise temperatures beyond safe levels, harming the worm population.  
• Maintaining proper moisture levels dry conditions can be fatal to worms, while waterlogging forces them to leave. Water daily in summer and every third day during the rainy and winter seasons.  
• Limit acidic waste avoids adding large amounts of tomato and citrus waste, as excessive acidity can harm the worms.  
• Ensure proper drainage by creating a channel around the heap, especially in high-rainfall areas, to prevent water stagnation.  
• Use only organic and biodegradable materials to remove stones, plastics, glass, ceramic, and other non-degradable items before composting.  
• Protect against natural predators, including ants, termites, centipedes, rats, pigs, and birds.  
• Apply preventive measures to treat the site with a 4% neem-based insecticide before filling the heap to deter pests.  

7.0Transportation of live worms 

• Live earthworms can be packed with moist feed substrate in a container (cardboard/plastic) with aeration provided. 
• Feed substrate quantity should be 0.5-1.5 g/individual for 24 hours of transportation journey. 
• Culture should contain cocoons, juveniles, and adults because sometimes adults do not acclimate to new environments and may even die. 
• Under such circumstances, cocoons are helpful for the population build-up of earthworms.

Application rate 

• It can be applied in any crop at any stage, but it would be more beneficial if mixed in the soil after broadcasting. The rate of application is as follows: 
• Field crops 5-6 t/ha; 
• Vegetables 10-12 t/ha; 
• Flower plants 100-200 g/sq ft; 
• Fruit trees 5-10 kg/tree.

8.0Advantages of vermicompost 

• Nutrient-Rich: Vermicompost contains high levels of essential nutrients, vitamins, enzymes, antibiotics, and growth hormones, making it more beneficial than traditional composts.  
• Enhanced Microbial Activity: It supports beneficial microbes that aid in nitrogen fixation and phosphorus solubilization, improving soil fertility.  
• Improves Plant Growth: Application of vermicompost promotes nodulation in legumes and enhances symbiotic mycorrhizal associations with plant roots.  
• Ideal for Nurseries: It serves as an excellent rooting medium for establishing saplings in nurseries.  
• Continued Soil Enrichment:  Contains enzymes such as protease, lipase, amylase, cellulase, and chitinase, which help in the decomposition of agricultural residues, facilitating further microbial activity.  
• Odor-Free: Unlike traditional manures and decaying organic matter, vermicompost does not produce a foul odor, making it more user-friendly.  

9.0Harvesting of the Vermicompost from the Pit

• Stop watering one week before harvesting  to allow the compost to dry slightly for easier separation.  
• Worm clustering: Occasionally, earthworms gather into compact balls in a few spots within the pit. These clusters should be carefully removed and placed in a bucket.  
• Compost separation: The compost is heaped by manually disturbing the top layer, prompting earthworms to move downward. This allows easy collection of the compost from the upper layers.  
• Replenishing feed material: Once the compost is collected, fresh organic material is added to restart the composting cycle.  
• Final processing: The harvested material is sieved using a 2 mm sieve, separating the fine vermicompost from larger particles. The sifted compost is then stored in bags for use. 

10.0N P K Content in Vermicompost, Farmyard manure and bacterial compost

Other nutrient Contents

• Organic carbon 9.15 to 17.98 % 
• Available S 128 to 548 ppm 
• Copper 100 ppm 
• Iron 1800 ppm 
• Zinc 50 ppm 
• Ca and Mg