FARMING depends heavily on fertilizer to increase crop production. The use of chemical fertilizers, for instance, has been an important part of the Green Revolution in the past.

While inorganic fertilizers are essential for high yields, their long-term use produces deleterious effects on the soil.

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This is the reason that experts are now recommending using organic fertilizers. Earthworm castings or vermicompost is one important form of organic fertilizer, which farmers can readily use in their farms.

Vermicomposting in the Philippines began in the 1970s with studies conducted by researchers of the Central Luzon State University in Munoz, Nueva Ecija. However, it did not take off as expected.

It was not until Dr. Rafael D. Guerrero III, director of the Laguna-based Philippine Council for Aquatic and Marine Research and Development (PCAMRD), took a second look at the technology that it started to gain popularity.

Dr. Guerrero wanted to utilize vermicomposting to improve soil fertility, reduce costs, and mitigate pollution in the Philippines.

"We have a robust agricultural economy with our extensive land and water resources," he said. "The production of crops such as rice, coconut, and sugarcane, along with fisheries (aquaculture), is the mainstay of our agricultural base."

He found out that one of the major constraints in the production of crops and fish in the country was the high cost of inputs, particularly imported chemical fertilizers, for crop production and feeds for aquaculture. Of environmental concern was the widespread burning of crop residues such as rice straw and sugarcane trash.

"About 24 million tons of rice straws are generated annually," Dr. Guerrero said. "Livestock manure poses additional challenges. Approximately 28 million tons per year are generated, and improper discharge into water bodies is causing aquatic pollution and fish kills."

So, he thought of turning these wastes into organic fertilizer using vermicomposting or the process of converting biodegradable wastes from households and farms into compost (organic soil) through the action of earthworms.

"With the aid of aerobic microorganisms (that is, bacteria and fungi), earthworms digest processed organic materials under favorable temperature and moisture conditions," Dr. Guerrero further said. "The materials that pass through the digestive tract of the earthworms come out in a texturized, sanitized, and deodorized form of castings known as vermicompost."

Vermicompost is richer in nutrients than compost produced by other composting methods. It is also rich in microbial life, which helps break down nutrients already present in the soil into plant-available forms. Unlike other compost, worm castings also contain worm mucus which keeps nutrients from washing away with the first watering and holds moisture better than plain soil.

There are three earthworm species which have been used to produce vermicompost in the Philippines. Of the three, the African nightcrawler (introduced in 1982 from Germany) is the most efficient for vermicomposting under Philippine conditions. "It matures in six weeks and can be bred as often as once a week," Guerrero said.

In Davao del Sur, one organization that is promoting vermicomposting is the Mindanao Baptist Rural Life Center (MBRLC) Foundation Inc. "We found out that vermicompost is good for vegetables and even fruit trees," said Mario V. Continedas, the center's farm manager.

In an experiment conducted on eggplant, results showed that a combination of vermicompost at 100 grams per pot (6.2 tons per hectare) and 50 percent of the recommended chemical fertilizer application gave a significantly higher yield (15 percent more) of eggplant fruits, compared to that with 100 percent chemical fertilization, after 120 days from planting.

The MBRLC offers two-day training on vermicomposting. It also produces an 8-page manual on vermiculture. For further details, visit the farm or e-mail them at mbrlc@mozcom.com. The phone number is 064-533-2378.

The local markets for vermicompost are big. In 1993, the potential use of organic fertilizer covered 2.5 million hectares in the Philippines. That year, 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.

"Intestines of the soil" was how Aristotle called earthworms while Cleopatra decreed them sacred. "It may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly, organized creatures," Charles Darwin stated. The Chinese character for earthworms translates as "angels of the earth."

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(December 1, 2008 issue)
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