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African
night crawlers are revitalizing the soil and playing a major role in solid waste
management
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For
almost two decades now, a species of earthworm from
Africa
has been revitalizing the soil of this Southeast Asian nation, giving it the
nutrients it needs.
The African night crawlers are also expected to contribute much in the
management of solid wastes in the years to come.
Scientifically known as Eudrilus euginae, these African earthworms are
the main characters of vermicomposting in the
Philippines
.
Vermicomposting is a form of composting that utilizes earthworms to convert
organic wastes like food waste, plant material and animal manure into
vermicompost.
Earthworms
feed on the decaying organic material and, with the aid of microorganisms in
their digestive tract, the organic wastes are excreted as castings or worm
manure, called vermicompost.
Those
into vermicomposting like Pamela Henares say the African night crawlers, which
were brought into the country in the 80s and have since adapted to the
environment here, are the “most-effective species.”
Together
with her husband Jose, she put up a farm that is now one of the top models of organic farming and vermicomposting in the country.
She
started vermicomposting to meet the demands of her farm. But today, Henares is
not only growing the African night crawlers for her own use; she also sells the
worms and promotes vermicomposting in the management of solid wastes.
African
Worms
in Waste Management
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World
consumption of organically grown foods is estimated at US$ 100 billion per year
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Food and yard wastes make up 44.5 percent of the typical municipal solid waste
produced in the
Philippines
.
In
the capital Metro Manila, according to the Presidential Task Force on Waste
Management, household waste is composed of 41-57 percent kitchen wastes, 5-17
percent grass and wood wastes, 12-16 percent paper and the rest are
non-biodegradable wastes.
But
only a small percentage of this organic waste is composted or used as animal
feed, while a large portion of this waste is disposed off to municipal
dumpsites.
“Why
not go into vermicomposting?” Henares asked local government officials
gathered in Iloilo
City
for a seminar on ecological solid waste management sponsored by the Canadian
government.
She
describes the technology as “environment-friendly, doesn't require imported
inputs, highly profitable when sold, more effective as an organic fertilizer
than ordinary compost, humus, no burning of plants, has a naturally occurring
growth hormone called auxin, no overdosage, and improves soil health.”
“It
has been discovered through experiments and actual experiences that
vermicomposting reduces organic waste to one-third of its original size. This
would minimize the need for landfills and dumpsites,” Henares told 80 mayors
and local government officials.
She
added that the “recycling technology” could be employed to convert organic
wastes into vermicompost, or high quality fertilizer. The fertilizers, which
could be commercially sold, can contain up to 8 percent nitrogen, 0.7 percent
phosphorus, 1 percent potash and trace elements.
“The
vermicompost is also an excellent source of organic matter for potting mixes and
nursery plants, and of nutrients badly needed by topsoil-depleted farmlands. It
can also be used as an organic fertilizer for ornamental plants, vegetables and
field crops.”
Henares
said local governments should resort to this cheap, environment-friendly
technology instead of buying expensive waste-management machineries and
equipment. “It could also make your towns earn money. It turns trash to
cash,” she pitched to them.
She
added that world and local markets for vermicomposting are big. World
consumption of organically grown foods is estimated at US$ 100 billion per year.
In
1993, the potential use of organic fertilizer covered 2.5 million hectares in
the
Philippines. The demand for organic fertilizer in 1993 was 6.25 billion bags (50 kg/bag)
compared to actual consumption of only 62,000 metric tons.
African
Worms
and Organic Farming
Pamela
Henares along with husband Jose discovered vermicomposting through an article by
Dr. Rafael Guerrero published in Agriculture Magazine.
In
October 1998, the Henares couple started to turn their 18-hectare land into an
organic farm, which is now one of the country’s top producers of African night
crawlers.
The
farm, located in Talisay
City,
Central Philippines
, now produces plenty of organically grown vegetables and fruits. It also has
mini forests and a variety of fruit trees. Part of it is also used for raising
and keeping livestock and poultry.
The
wastes generated in their farm became a resource for their vermicomposting
facility. For the past four years, they have not purchased inorganic fertilizers
but instead have utilized the vermicompost they produced for their farm.
Buyers
of earthworms produced by Buro-Buro Vermi Farm, which are current and potential
adopters of vermicomposting, come from different places across the country.
Vermicomposting
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Vermicomposting
can be a very profitable business
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The vermicomposting process involves four general phases: collection and
preparation of materials, anaerobic (without oxygen) decomposition, aerobic
(with oxygen) decomposition and harvesting of vermicompost.
To
start vermicomposting, Henares explains, there are four factors that need to be
considered: site selection, earthworms to be used, materials for composting, and
the vermicomposting process.
A suitable site for vermicomposting should have adequate water supply and good
drainage. It should also be close to the source of materials and must be well
shaded.
The
earthworm preferred by Henares is the African night crawler. They can breed as
often as once a week, producing an egg capsule that contains 1-3 young that
mature in less than 30 days from hatching.
These
worms are not harmful to man or domestic animals. They are cold-blooded, breathe
through their skin and have a nocturnal habit (tend to shy away from light).
These
worms can live up to two years and grow up to 30 centimeters (1 foot). They
thrive best at temperatures of 24-28°C, with moisture content of 60-80 percent.
Materials
used in vermicomposting are kitchen wastes (not including oil, meat and dairy
products), garden wastes such as grass clippings and leaves and animal wastes.
These
compostable materials can be degraded more quickly if they have small particle
size to increase the surface area for microbial action. Thus, shredding and
pulverizing bulky materials is helpful.
In
preparing the materials or substrate, it is important to remember that the
proper proportion of cellulosic (high carbon) and nitrogenous (high nitrogen)
components must be maintained for rapid composting.
The
desirable carbon-to-nitrogen range is 25-35:1.These materials are then mixed
thoroughly. Water is added to obtain a moisture content of at least 80 percent.
For
vermicomposting done inside a limited space, the substrate can be placed in
containers such as wooden boxes, plastic bins and old drums. The height of the
containers or bins should not exceed 30 centimeters (12 inches).
The
length and width of the bin will depend on whether it is to be stationary or
portable. It also depends on the amount of organic waste to be composted per
week. It is advisable to provide 0.2 square meter of surface area per kilogram
of waste in the bin.
For
vermicomposting units located outdoors like on the farm or in the backyard, the
substrate can be heaped in beds or windrows, which may be lined at the sides
with bamboo walling or other forms of retaining devices such as screens and
blocks. Beds can be stacked at a maximum height of 60 cm (2 feet) for aeration
by earthworms.
The
next step is the anaerobic stage wherein the bed is covered with a plastic sheet
to step up the natural decomposition initiated by anaerobic bacteria. The
temperature of the substrate in this stage can reach 50-70° Celsius. “The
higher the temperature, the faster the decomposition would take place.”
This
phase may last for one to two weeks. When the temperature of the substrate goes
down to ambient condition (24-28° Celsius), the plastic cover of the
vermicomposting unit is removed.
Aerobic
decomposition proceeds by stocking live earthworms into the substrate at the
rate of one kilogram of worms per 20-30 kilograms of substrate (dry weight).
The
vermicomposting units should be watered when necessary to maintain the optimum
moisture content of 60-80 percent (when a fistful is squeezed, 3-5 drops of
water should drip).
The
worms need to be protected also from their predators such as birds, rats, toads
and from flooding. The rate of vermicomposting depends on the density of
earthworms, the substrate composition (carbon-to-nitrogen ratio) and
environmental conditions (temperature and moisture content).
The
more worms stocked, the faster the production of castings. When the substrate is
fully composted in four to five weeks (28 to 35 days), the vermicompost can be
harvested.
The
earthworms are first removed from the pile by hand or through a mechanical
sorter and then the compost is air-dried for two to three days to a moisture
content of 30 percent.
Henares
proudly said she was able to convince a number of people to go into
vermicomposting and organic farming. “And they have told me vermicomposting
didn’t fail me.”
Now,
the former hospital administrator hopes local government leaders will listen to
her and heed her advice to use the African night crawlers in turning the
town’s solid wastes into composts and organic fertilizers. “It would solve
their garbage problem and would even make their towns and people earn money.”
Rexcel
John B. Sorza is a journalist from the Philippines
and a Bachelor of Arts in Broadcast Communication and Management. He was
recently the runner up in the Water Media Network Journalists’ Competition and
received his award at the
Third World
Water Forum in Kyoto,
Japan.Your emails will be forwarded to him by contacting the editor at: ScienceTech@islam-online.net.
