Species for Vermi-composting
Earthworm can be divided as surface living (epigeic) and burrowing (epianecic) worms. Epigeic or compost worms are found on surface and are reddish brown eg. Lumbricus rubellus (red worms). Of many species of earthworms tested for mass culture all over the world, Eisenia fetida, Eudrilus eugeniae and Perionyx excavatus come in the above order of preference for their ability to compost organic wastes. The shapes of cocoons of Eisenia frtida and Eudrilus eugeniae are dissimilar.

Rearing of earthworms The worms are reared and multiplied from a commercially obatined breeder stock in shallow wooden boxes of 45 cm *60 cm, provided with drainage holes and stored on shelves and tiers.
A bedding material is compounded from miscellaneous organic residues saw dust, cereal straw, rice husks, sugarcane trash, bagasse, paper, cardboard, coir waste, grasses etc. and is moistened well with water. The wet mixture is stored for 30 days covered with a damp sack and is throughly mixed several times. When fermentation is complete, chicken manure and green matter eg. Leucaena leaves or water hyacinth is added. The material is placed in the boxes in the ans sufficiently loose for the worms to burrow and should be able to retain moisture. the The proportion of the different materials will vary according to the nature of the material but a final nitrogen content of about 2.4% should be amied at. A pH value as near neutral as possible is necessary and the boxes should be kept at temperatures between 20⁰C and 27⁰C. At higher temperatures the worms will aestivate and at lower temperatures they hibernate. for each 0.1 m² of surface area 100 g of breeder worms are added to the boxes. Inspite of their being able to eat the bedding material, the worm at this stage are regularly fed @ 1 kg of feed a day for every kg of worms. the feed stuffs used are again various types of organic matter and include partially digested cowdung, chicken manure, Leucaena leaves, vegetable waste and water hyacinth. Some form of protection against predators like birds, vats, ants, frogs, leeches and centipeded is provided to the worms.

VERMI-COMPOSTING IN PITS
A number of pits 2m *1m with sloping sides aredug having suitable dimension. Vermi-composting is done in pits and in vitro. Both of these are discussed here.
Bamboo poles are laid in paralled row on the pit's. Its floor is with a lattice of wood strips. Necessary drainage is provided because worms can not survive in a waterlogged condition. Alternatively to this and sand can be placed in the bottom of the pit to facilitate proper drainage. Above this a thick layer (15-20 cm) of good loamy soil should be spread. The pit can now be filled with available organic residues such as animal manure, leaves and green weeds, crop residues etc. Moisture levels of the contents of pit is maintained through addition of required amount of water. The worms from breeding boxes are introduced in the organic refuse, the worms immediately burrow down into the damp soil.
The compost pit is left for 60 days. It should be shaded from hot sunshine and it must be kept moist. Within 60 days about 10 kg of castinge would have been producer per kg of worms. The pit is then excavated to an extent of about two-thirds to three-quarters and the bulk of the worms removed by hand or by seving. This leaves sufficient worms in the pit for further composting and the pit can be refilled with fresh organic residues and continued.
The compsost can be sun-dried and sieve to give a good quality compost. The average nutrient content of vermi-compost is N 0.6-1.20%, P₂O₅ 1.34-2.20%, K₂O 0.4-0.67%, CaO 0.44% and MgO 0.15%.
The excess worms that have been harvested from the pit can be used in the other pits, sold to other farmers for compost inoculation, and may be used as animal and poultry feed or fish food.

Method of pit vermi-composting
Selection of earthworm : Earthworm which is native to the local soil and vermi-compost may be used.
Size of pit : Any convenient dimensions such as 2m * 1m *1m may be prepared. This can hold 20,000-40,000 worms giving 1 tonne manure/month (30 days).
Preparation of vermibed : a 15-20 cm thick layer of good loamy soil above athin layer (5cm) of broken bricks and sand should be made. This layer is inhabited by earthworms.
Inocluation of earthworms : About 100 earthworms are introduced as an optimum inoculating density into a composit pit of about 2m * 1m * 1m provided with a vernibed.
Organic layering : It is done on the vermibed with fresh cattle dung. The compost pit is then layered to about 5 cm with dry leaves or hay. Moisture content of the pit without flooding is maintained through the addition of water.
Wet organic layering : It is done after 28 days with moist/green organic waste which can be spread over it to a thickness of 5 cm. This practice can be repeated every3-4 days. Mixing of wastes periodically without disturbing the vermibed ensures proper vermi-composting. Wet layering with organic waste can be repeated till the compost pit is nearly full.
Harvesting of vermi-compost : At maturation, the moisture content is brought down by stopping the addition of water for 3-4 days. This ensures drying of compost and migration of worms into the vermibed. The mature compost, a fine loose granular mass is removed out from the pit, dried and packed.
Rate of application : Mature vermi-compost is recommended @ 0.5 tonnes/ha.

To boost vermi-compost production production following suggestions should be followed :
(i) A mixture of cattle, sheep, horse dung with gram and wheat bran and vegetable wastes forms the ideal feed for worms.
(ii) Mixing of gram bran with dung mixture in 3:10 ratio increase the biomass.
(iii) Mixing of wheat bran to dung mixture in 3:10 ratio hastens the growth of worms. Addition of kitchen waste in the same proportion increases the worm population.
(iv) The biogas sludge and poultry dropping in equal quantities enhance the worm population and the biomass.

In-vitro vermi-composting
This is also called as bioconversion in soil. This involves the application of the basal dose (5 tonnes/ha) of vermicastings and covering with 2.5 cm. Layer of organic mater (cowdung or pressmud) followed by 10 cm layer of sugarcane trash, crop residues or city swastes. The worms hatch out within 10 days.

Vermi-composting of agricultural wastes
With the aim of vermi-composting of agricultural wastes an experiment was conducted at the Indian Agricultural Research Institute, New Delhi. The usefulness and efficiency of earthworms in composting of agricultural residues was studied.
Two trials were conducted with mixed organic materials. Trial A, had more of green materials like grasses and Leucanena leaves mixed with soil and paper. Experient B had 4 kg of composting materials consisting of 2 kg of paddy straw, 1 kg soil 500 g twigs, and 500 g shredded paper and was laid in layers per pit. The bottom most layer was laid with twigs to allow for percolation of excess moisture. The compost pit was kept moist and care was taken to avoid waterlogging.

Source : Indian Agricultural Research Institute, New Delhi.
After 10 days of initial decomposition, worms (Eisenia fetida) obtain from M/s Biogenic Ltd., Mumbai were introduced @ 100 worms/pit. Afterthe worms burrowed into the deeper layers, the pit was coveredwith a thin layer of soil.
The results of both of the trials (Table) show that introduction of worms in the organic matter piles was found helpful in composting. Organic carbon was reduced at different intervals of composting. In the inoculated compost, nitrogen content wwas appreciably augmented and the C:N ratio was narrowed to a desirable level. The worms were also active in decomposition of high C:N ratio of compost was brought to 51 only whereas with worms it was narrowed down to 21. The use of worms also increased the available phosphorous content of compost. Conjoint use of cellulolytic fungi and earthworms showed better result then other of them alone.

(3) Town compost. In recent years, large-scale composting of town refuse and night-soil in properly constructed trenches away from human habitations has been taken up successfully by the municipalities of many large and small towns. Trenches, 1 to 1.2 m wide, 75 cm deep and of convenient length, are filled with successive layers of night-soil, town refuse and earth, in this order. The compost gets ready in about three months. The following figures of volume-weight conversion will be found useful in the preperation of town compost.

Volume		Weight in kg or q
1 cu.m of refuse	=	318 kg or 3.18 q
1 litre of night-soil	=	0.991kg
1 cu. m of compost	=	636 kg or 6.36 q
1 cartload of refuse(0.849 cu. m),/font>	=	95.40 kg

Social prejudice against the use of this valuable compost has disappeared and town-composting is almost being rapidly adopted in other localities all over India. With a suitable modifications, such as the provision of trench latrines, it can be taken up in villages too. Particulars of the process may may be obtained from the National Extension Service Officers.

(4) Sewage and sludge. The liquid waste, like sulage and sewage contain large quantities of plant nutrients and are used for growing of sugarcane, vegetables and fodder crops near many large towns by operating sewage-farms. In many places, the undiluted sullage has been found to be too strong for healthy plant growth and if it contains readily oxidized organic matter, its use actually reduces nitrates present in the soil. The disadvantages are still greater if sewage is used on land without preliminary treatment. The soil quickly becomes 'sewage sick' owing to the mechanical clogging by colloidal matter in the sewage and the development of anaerobic organisms which not only reduce the nitrates already present in the soil but also produce alkalinity. Bacterial contamination makes the eating of raw vegetables on untreated sewage a real danger to health.

For these reasons, it is now usual to construct a setting or a septic tank in which sewage is stand allowed to relieve it of the heavier portion of the solid matter in it, or to undergo a preliminary fermentation. The effluent from the settling-tank, however, still carries a large amount of objectionable colloidal matter, and the deposit of sludge that settles in the tank is of small manurial value and is often offensive. These defects can be removed by thoroughly aerating the sewage in the settling-tank by blowing air through it. The sludge that settles at the bottom in this process is called 'activated sludge' It has the remarkable property of bringing about the rapid oxidation of the organic matter present in fresh sewage. It is also in offensive and on dry-weight basis, contains 3 to 6 per cent N, about 2 percent P₂O₅ and 1 per cent K₂O in forms that can become readily available when applied to the soil. Similarly, the effluent is a clear, odourless liquid containing nitrates in solution, from shich most of the pathogenic bacteria originally present have been removed. Both the activated slidge and the effluent can be used with safety for manuring and irrigating crops. However, under no circumstances should any produce grown on a sewage-farm be eaten uncooked.