Earthworms that restore fertility and process sewage
by Stephen White
One of the articles in A Good Harvest (IC#42)
As managing editor ofWorm Digest, I had been writing about the joys of redworm vermicomposting in small, backyard bins for almost three years. Although I was aware of worm composting on a larger scale, I had yet to learn that worms could boost crop production up to 50 percent, bring dead land back to life, or filter sewage for hundreds of people. Then I met Uday Bhawalkar, founder of the Bhawalkar Earthworm Research Institute (BERI) in India, who is developing innovative ways of processing organic wastes using burrowing earthworms.
Bhawalkar, a farmer turned chemical engineer, and his wife, Vidual, an electronic engineer, established BERI in 1981 in Pune, a city of 2 million people in central-western India. Their vermiculture (worm-based) biotechnology processes are radically changing how people view wastes. In his efforts to educate people around the world about how earthworms can transform wastes into resources, Bhawalkar teaches that there’s no such thing as organic waste; only wasted organics.
In sustainable agriculture practices, vermiculture creates a healthy, living soil that is less subject to erosion and moisture loss. Because worms help increase the soil’s water-holding capacity, the need for irrigation has been reduced 40-60 percent in BERI projects. Soil with a healthy earthworm population is better aerated because it requires no mechanical tillage. The worms produce a soil teeming with microbial life that grows healthy crops subject to fewer damaging pests and diseases. Because worms respond poorly to chemical inputs, they serve as a natural deterrent to using chemical fertilizers or pesticides.
Worms Double Wheat Production
BERI has established six large-scale vermicomposting projects, and motivated nearly 5,000 farmers in 16 Indian states to use worms in their farming practices. Several experiments have proven that vermiculture can contribute significantly to crop yields and quality. In the Pune district, grape production increased 50 percent at a vineyard that employed earthworms. In Maharashtra State, vermiculture helped stabilize soil pH and increase potash (a type of potassium and key plant nutrient) content of the soil. In Auroville, Southern India, worms are credited for doubling wheat production and quadrupling grass pasture production. Savings on input costs such as fertilizer and water have dramatically increased profits.
In India, where two thirds of the cultivable land has degraded soil and 325 million acres have turned into wasteland, vermiculture has helped transform unusable areas into land suitable for planting. Burrowing earthworms are capable of breaking down the toughest of wastes, such as sugarcane trash, feathers, or bones. Even land that has become saline is being recovered.
Significant advances in waste treatment have been made by BERI in India and other countries for both solid wastes (municipal wastes and livestock manure), and waste waters (from cities and agro-industries). The worm excrement (called castings) is used as biofertilizer.
A project that began in 1991 at Sanjeewan School at Panchgani in Maharashtra, India, uses a vermifilter – a filter employing earthworms – to process sewage for 550 students. The vermifilter uses vermicastings, beneficial (aerobic) bacteria, a plant root matrix, and burrowing earthworms.
The worms inspiring these new technologies are burrowing earthworms. According to Bhawalkar, a common fallacy is that all earthworms behave in the same way. In fact, there are 3000 known species, which can be divided into two classes: manure worms (redworms) and soil-processing worms (earthworms). Redworms are commonly used in worm bins. They consume and stabilize organic residues on the surface of the earth and can be found “in the wild” under leaves, rocks, or other debris. Although they vary slightly from continent to continent, earthworms are the big, iridescent gray worms commonly known as night crawlers. The key difference between the two classes of worms – and the key to BERI’s success – is that the burrowing worms actually process the soil.
Burrowing worms have 600 million years of experience as “biomanagers” of the soil, where they supervise aeration, moisture content, and bacterial activity. The burrowing worms take their cues from the plants, creating the conditions that provide the needed nutrients, antibiotics, and hormones for healthy growth. According to Bhawalkar, earthworms are the managers while bacteria are the workers, speedy and diverse bioprocessing agents that voraciously consume organics, producing a wide range of nutrients (nitrogen, phosphorous, vitamins, antibiotics, hormones, etc.) for the plants.
By promoting the beneficial aerobic bacteria in the soil, earthworms help them out-compete pathogens, which grow at a slow rate outside their host. Earthworms sense these slow-growing microbes, cull them from the beneficial bacteria, and use them as food. This ability to suppress pathogens has been found in only one other process: thermophilic composting – wherein the compost’s high temperature kills both the pathogens as well as the beneficial soil bacteria.
The earthworm’s gut is a bio-reactor, providing all of the proper conditions (temperature, moisture, pH, air, etc.) for the rapid proliferation of beneficial bacteria. The impressive results yield worm excrement or castings that are 1,000 times more microbially active than the surrounding soil.
Bhawalkar’s first large-scale project in the US, which began in the fall of 1994, is located at the Banks of Eden farm in Eden, Maryland, where a standard composting facility has been converted to a vermiculture facility.
This location will be the “verminursery” for other sites across the country as the biofertilizer (vermicastings with earthworm cocoons and a wide spectrum of beneficial microorganisms) created there will be used to start other vermiculture projects. University of Oregon in Eugene, is one such site, where a vermiprocessing project will process in excess of 2000 lbs. of campus food waste generated daily.
While we wait for the biofertilizer from Maryland, I and several others have begun employing Bhawalkar’s method on a small-scale to verify the efficacy of feeding organic wastes to the soil. Any gardener or farmer who mulches knows that in time, the mulch decomposes. But how many gardeners or farmers have tried burying their kitchen food wastes (vegetable-based) under the mulch? I have found that it is simpler to place it there than to put it into a worm bin that requires management and harvesting. After spreading it beneath the mulch along with a sprinkling of rock dust and a little water, I forget about it. The food waste is consumed within two to three weeks in most cases. And, I have a truly wonderful population of large burrowing earthworms, that, if Bhawalkar’s theories are accurate, are managing a voracious bacterial population to make this possible.
Stephen White, artist, environmental educator, managing editor of Worm Digest, plans to someday live in a house where almost nothing is wasted, and earthworms do much of the work to make that possible. For worm resources, see Resources section in this issue.