Toilers of the soil: the earthworm workers

Carmen Nottingham’s earthworm farm
north of ­Johannesburg is more than just
a business; it is her way of helping to
restore South Africa’s depleted soil.
She is in league with the earthworms to
produce Fertilis fertiliser – she feeds them with dairy cow ­manure, and the
earthworms’ castings are the ­product.
Wilma den Hartigh visited the farm.
Issue date 1 June 2007

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CARMEN NOTTINGHAM’S INTEREST in earthworms came in a roundabout way. At university she studied languages and industrial relations, but never pursued a career in this field. It was living and working on a yacht in the Caribbean for eight years that first sparked an interest in biology. “Here I saw the destruction of the coral reefs. I returned to South Africa to study marine biology, but instead landed up in Johannesburg, far away from the sea. I decided to view the soil as the ocean of the land. Earthworms are like plankton in the ocean. They help to create the food base for all life,” she says. She started farming with Eisenia foetida earthworms, commonly known as red wrigglers, on her smallholding north of Johannesburg in 2001. Although there are over 5 000 earthworm species, this is one of only three commercially viable species that will thrive in a waste ­management and recycling operation. “In terms of waste management, they are phenomenal,” she says, adding that this earthworm can also be used in management of human, animal and food waste. The earthworms live in five 60m x 3m trenches. The trenches are exposed to direct sunlight, and the earthworms are most active at night and early morning. “This is when they do their work,” Carmen says. As earthworms are very sensitive ­organisms, the trenches are shaded from excessive heat and light with dark plastic during the day. “The earthworm’s whole body is a sensory organ,” she explains. The open trenches are ideal for the earthworms because in the event of extreme heat or too much rain, they can burrow deeper in. “I don’t make prisoners of earthworms.”

The process

In a day, an earthworm can consume manure equivalent to its body weight, says ­Carmen. It moves by continuously ­burrowing, ­ingesting material, digesting it and depositing the remains. Ingested material passes through calciferous glands that neutralise its pH. “The gut of the earthworm is very oxygen-rich, and many ­microorganisms are deposited in the ­castings,” she says, adding that this makes the Fertilis product rich in oxygen and microbes. When the manure is ready, it is collected from the trenches, and any stones, earthworms and earthworm cocoons are sifted out. She says the manure always contains stones, as cows often swallow stones to get minerals. “When you start out, it will take about nine months of feeding and breeding before the process can become ­continuous. The more earthworms you have, the more manure can be converted. The way to do it is to ­continue feeding some trenches while sifting ­others. If you want to ­produce more, then feed quicker.” Three tons of cow manure will produce one ton of sifted Fertilis, but the potential food value of a ton of Fertilis can be up to 30 times that of plain manure.

Markets and growth

Her earthworm enterprise has grown along with the increasing demand for organic products and more sustainable ways of farming. “This growth did not take place overnight,” she recalls. “We ­experienced slow but constant growth. The number of trenches on the farm does not determine the viability of the business. Turnover is the actual indicator. We had 100% growth in the business last year.”
The nursery and farming industries are her main markets. The company Talborne Organics distributes her product to ­nurseries and farmers in Gauteng, Mpumalanga, KwaZulu-Natal and the Cape. The nursery market caters primarily for gardeners, but farmers can purchase Fertilis in bulk directly from the farm. In the commercial ­farming sector her product is successfully used in the planting of seeds and seedlings. Carmen also ­supplies large-scale farmers with the ­Fertilis fertiliser to produce compost tea. The fertiliser, dissolved in water and strained, is sprayed on to crops by commercial farmers.

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Carmen is expanding her business into the Western Cape. She admits the expansion will entail more than setting up shop in another province. She won’t be able to use open trenches, as Cape winter conditions are too wet. “The earthworms won’t adapt well to extremely wet conditions,” she says. Further growth opportunities lie in waste management, and recycling and growing earthworms for food in the aquaculture industry. Transporting dairy manure is one of her biggest costs, and for this reason Carmen advises that an earthworm farm should ideally be established on or near a dairy farm. She says it can be beneficial for a farmer to start an earthworm farm, but many conventional farmers see ­processing manure as an additional cost. “But in the long run it can save the farmer lots of money,” she says, adding that the ­greatest benefit of ­converting manure is that it creates a sustainable ­farming ­operation. “Waste must be used as an input for another production process. It is only in this way that sustainability can be created.”

As earthworm farming is very labour-intensive, labour is a major cost. Fortunately her business doesn’t require expensive mechanisation. “It is a hand process to mix manure and put it in the trenches. The earthworms do most of the work,” she says, adding that sifting and bagging is also done by hand. She cautions ­prospective earthworm farmers to obtain the manure from a reliable source – the earthworms will die if any antibiotics, in particular dewormers, are present in the manure.
Carmen recommends a farmer starts by rehabilitating a small field first. She ­estimates that it will take about two seasons to rehabilitate soil. “It is never too late to start. One person can do a lot,” she says. She believes it can be more cost-­effective to farm organically. Initially the farmer will have to spend more to restore the soil’s balance, but once this is achieved the long-term costs will be reduced. “The farmer will have to use less ­chemical fertiliser because the plant will not be dependent on ­chemicals any more,” she says, adding that plants will be stronger, there will be less pollution of ­groundwater, soil health will be improved, and ­nutrient levels of plants will be higher.”

Contact Carmen at (011) 888 4215 or Talborne Organics at (011) 954 5763. |fw