|
|
ECO-FRIENDLY TECHNOLOGIES
AGRICULTURAL TECHNOLOGIES
VERMICOMPOSTING
-
In
India nearly 700 million tons organic waste is generated annually, creating
disposal problems. Most of these organic residues are burned currently or used
as land fillings, (Bhiday,
1994). But in
nature’s laboratory, earthworms are important biological organism that have
the ability to convert organic waste into valuable organic manure containing
plant nutrients and also minimize environmental degradation. There is a
tremendous scope to convert the biodegradable waste into organic manure
through vermiculture biotechnology or vermicomposting
(Arora et al., 2002).
-
The
term vermiculture biotechnology denotes the use of earthworms as natural bio
reactors for efficient biodegradation of organic solid wastes. The earthworms
ensure bio-conversion of waste in to rich manure within 40-45 days under
complete aerobic conditions.
-
In
vermicomposting composting process, certain species of earthworms are used to
enhance the process of waste conversion.
-
Vermicomposting differs from composting in several ways
(Gandhi et al., 1997).
It is a mesophilic process, utilizing earthworms and microorganisms that are
active at 10–32°C.
-
The process is faster than composting; because the material passes through the
earthworm gut, a significant but not yet fully understood transformation takes
place, whereby the resulting earthworm castings are rich in microbial activity
and plant growth regulators, and fortified with pest repellence attributes
(Vermi Co, 2001 & Tara Crescent, 2003).
-
Earthworms consume various organic wastes and reduce the volume by 40–60%.
Each earthworm eats waste equivalent to its body weight and produces cast
equivalent to about 50% of the waste it consumes in a day.
Varieties of Earthworms:
-
In
vermicomposting, special variety of earthworms are used which are adaptive to
the special conditions like rotting vegetation, compost and manure piles.
-
The species of earthworms that are being used for compost production are:
Eisenia foetida, Eudrilus eugeniae, Perionyx excavatus, Lumbricus rubellus
and Pheretima elongata.
Importance of Vermicompost:
-
Besides efficient waste management this technology provides excellent
employment Opportunities through sale of worms & compost.
-
Unlike chemical fertilizers the vermicompost is gentle & does not burn plants.
Its application in the soil results in:
-
Improved soil aeration
-
Improved structural stability of soil.
-
Increased water penetration into soil
-
Improved crop growth and yield
-
Reduction in soil C:N ratio
-
Supply of nutrients such as N, P, K, micronutrients
and plant growth hormones to the plant
-
Solublization of inorganic plant nutrients deposited
in the soil.
-
Neutralization of highly acidic & alkaline soil.
-
Control of plant pathogens & reduced pest attacks.
-
Increased beneficial micro flora like nitrogen
fixers, phosphate solublizers & actinomycetes.
-
Better lusture, taste & keeping quality of produce.
-
The worm castings contain higher percentage (nearly
two fold) of both macro and micronutrients than the garden compost.
Nutrient Composition of Vermicompost and Garden
Compost
|
Nutrient Element |
Vermicompost
(%) |
Garden Compost
(%) |
|
Organic Carbon |
9.8-13.4 |
12.2 |
|
Nitrogen |
0.51-1.61 |
0.8 |
|
Phosphorus |
0.19-1.02 |
0.35 |
|
Potassium |
0.15-0.73 |
0.48 |
|
Calcium |
1.18-7.61 |
2.27 |
|
Magnesium |
0.093-0.568 |
0.57 |
|
Sodium |
0.058-0.158 |
<0.01 |
|
Zinc |
0.0042-0.110 |
0.0012 |
|
Copper |
0.0026-0.0048 |
0.0017 |
|
Iron |
0.2050-1.3313 |
1.1690 |
|
Maganese |
0.0105-0.2038 |
0.0414 |
Source: Nagavallemma et al., 2004
Large Scale Vermicompost
Methodology:
A thatched roof shed open from all sides with
unpaved floor is erected in east-west direction lengthwise to protect the site
from direct sunlight. A shed area of 12’ *12’ is sufficient to accommodate three
vermibeds of 10’*3’ each having 1’ space in-between for treatment of 9 to 12q of
waste in a cycle of 40-45 days. The height of thatched roof is 8 feet from
center and 6 feet from the sides. The base of the site is raised at least 6
inches above ground to protect it from flooding during the rains. The periphery
of site is lined with rat poison to avoid the entry of rats. The vermin beds are
laid over the raised ground as per procedure given below:
-
The site marked for
vermi beds on the raised ground is watered & 4”-6” layer of biodegradable
agriculture residue is laid over it after soaking with water. This is
followed by one-inch layer of vermicompost or farmyard manure.
-
Earth worms are
released on each vermin bed at the following rates
Frequency
Loading
Daily 2”/bed/day
In bulk 12-15” (3-4 q/bed/cycle of 45 days)
-
The
loaded waste is finally covered with a jute mat to protect earthworms from
birds & insects.
-
Water
is sprinkled on the vermibeds daily according to requirements and season to
keep them moist. Moisture should be about 40 percent.
-
The
waste is turned upside down fortnightly without disturbing the basal layer (vermibed)
-
The
appearance of black granular crumbly powder on top of vermibeds indicates
harvest stage of the compost. Watering is stopped for at least 5 days at
this stage. The earthworms go down & the compost is collected from the top
with out disturbing lower layer. The first lot of vermicompost is ready for
harvesting after 2-2 ½ months and the subsequent lots can be harvested after
every 4-6 weeks of loading depending upon the type of waste treated.
-
The
vermibed is loaded for the next treatment cycle.
Source: Arora et al., 2002
Small Scale Vermicompost
Methodology:
The detail
for setting up a standard unit for vermicomposting of household garbage of
5-member family is as below:
-
Non-biodegradable waste such as glass, metal & plastic is to be separated
out at source by the resident.
-
Two
wooden/plastic containers having 10-15 drain holes and each have a dia of
3-5 mm at the bottom.
-
The
formation of base would be same as incase of large-scale unit.
-
Initially bucket is loaded with cow dung for 30 days than kitchen loading is
started.
-
The
loading weight would be 500g of kitchen waste daily (addition of citric
food, cooked food should be avoided).
-
After
the bucket is completely filled in, it is left for 30 days till compost is
ready after which the compost is harvested and the bucket is reloaded.
Some other
important points related to vermicomposting are listed below which have been
compiled based on the queries frequently received on this subject:
-
The
earthworms do not crawl out of the treatment site provide they are given
proper moisture, ventilation, and food with proper breeding.
-
The
vermicomposting does not stink if to is properly maintained.
-
The
earthworms can be safely touched as they do not cause allergy and don’t
bite.
-
The
earthworms are bisexual and can produce at very fast rate. A pair of earth
worms can produce 1500 off springs in six months under laboratory conditions
-
The
treatment unit does not attract flies if is properly maintained.
-
The
vermicompost is black, granular & earthly smelling.
-
The
water requirement for vermicomposting unit is:
Cereals: 2 tons /acre
Pulses: 2-3 kg per plant up to the age of 2 yrs
Vegetables crops: 5 kg per plant above 2 yrs of age.
Potted
plants : 3 parts soil and one part of vermicompost
Source: Arora et al., 2002
Eco-Friendly Agricultural Technologies
Page Revised on Sept. 2009
|
