Exploiting earthworms for fertilisers

  • 30/03/1994

Exploiting earthworms for fertilisers BUSINESS firms are cashing in on earthworms. These burrowers of the soil are miniature factories of natural fertilisers. They consume organic waste and their excreta, known as worm-cast, is gaining popularity as fertiliser because unlike chemical fertilisers, they do not pollute the soil and water.

One research study shows that after only 45 days of applying vermicompost in grape gardens, the availability of minerals such as calcium was comparable to that in plots on which chemical fertilisers were applied. Ganapathyrao Mhetre, a grape grower of Tasgaon near Pune, claims that vermicompost enabled a 2-year-old plant to grow as tall as a 10-year-old plant grown using chemical fertilisers. Moreover, vermicompost reduced the incidence of disease by boosting calcium and magnesium levels, he adds.

Besides providing compost, earthworms are good recyclers of garbage, says Uday Sawant, manager of the Pune-based Biogold, which sells worm-casts under the brand name Biogold Rich to tea gardens. Biogold is a subsidiary of Venkateshwara Hatcheries, where 15,000 chicken are killed every day.

Previously, the 4.5 tonnes of offal produced in the hatchery was sent to the municipal corporation's dump yard. But, realising the potential of vermicompost, the company took a loan from the National Bank for Agriculture and Rural Development, and now produces 2 tormes of worm-casts daily. According to Sawant, "Not only is the problem of waste disposal solved, the project also'stands on its own and generates its own income."

Tests by the company in 1992 showed that the use of worm-casts considerably reduced the occurrence of disease in grape fields and improved the taste of the grapes. The grapes also had a longer shelf life than those grown using chemical fertilisers and pesticides and so fetched Rs 2 more per kg. According to Sawant, one tonne of worm-casts, costing Rs 10,000, suffices as fertiliser for a one ha plot.

Sawant says he prefers deep burrowing earthworms to surface ones because they thrive even during dry spells and consume hard materials like offal. Deep-burrow worms can go down to three metres, whereas surface worms cannot burrow deeper than 2 inches. He adds that deep burrowing worms can live on 90 per cent soil and 10 per cent organic matter while the surface species are fully dependent on organic waste.
Surface worms advocated However, M R Bhiday, director of the Institute of Natural Organic Agriculture (INORA) in Pune, advocates the use of surface worms because they consume all types of garbage and multiply quickly. He argues that deep burrowing worms are slow converters of waste and also consume the fertile humus made by bacteria.

Besides selling worms and casts, INORA provides technical guidance for setting up vermiculture plants. It has got the contract for all the 43 military dairy farms in the country. The institute also has a vermiculture plant where NGOs and individuals are trained.

According to Bhiday, the pore space in soils with earthworms is greater and its water holding capacity is increased by 40 per cent. He adds that use of vermicompost also provides minerals that keep pests away. An INORA study reveals that income using vermiculture is Rs 9,662 per ha whereas it is Rs 7,518 per ha using chemical fertilisers. Bhiday says vermicastings have to be applied continuously for 5 years for the worms to establish themselves in the soil.

Another Pune-based organisation, the Bhawalkar Earthworm Research Institute (BERI), provides technical guidance on establishing waste recycling and vermicomposting units. Says Vidula Bhawalkar of BERI, "We mainly take up turnkey projects for solid and liquid waste processes. So far, 15 industrial units and NGOs have benefited from our guidance."

In Pune, earthworms are also being used to dispose of refuse in parks. Says Philip Virathan, president of Salisbury Park's citizens committee, "When the frequent complaints to municipal authorities went unheard, we brought in the earthworms to do the, cleaning".

However, there are people like Pradeep Apte, a consultant for the Maharashtra State Agricultural Marketing Board, who warn against being swayed by vermiculture. "Issues like improvement in soil health, crop yield, resistance to diseases and moisture condition have to be conducted in controlled agroclimatic conditions before making any drastic conclusion," says Apte.

Radha Kale, head of the zoology department at University of Agricultural Sciences in Bangalore, agrees and says, "Not all species of earthworms are useful for organic degradation." She adds that a comprehensive survey of the species and their potentiality has to be done. Kale says earthworms can also inhibit soil-borne pathogens, but the right species has to be identified.

Most organic farmers feel vermiculture should not be introduced from outside. "Vermicompost brought from a far off place may not be suitable for the local environment," says Vasant Futane, a farmer who stays near Warud town in Amravati district.

Also, there is no agency that certifies, fixes prices or monitors the quality of vermicompost. As a result, says Apte, "Vermiculturists sell treated soil in the name of vermicastings at the rate they wish."

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