SCIENCE
Worms Produce Another Kind of Gold for Growers
By JIM ROBBINS
Published: December 31, 2012
SONOMA, Calif. — Under rows of old chicken sheds, Jack Chambers has built an empire of huge metal boxes filled with cattle manure and millions of wriggling red worms.
“My buddies all had planes and boats,” said Mr. Chambers,
60, a former airline pilot. “I have a worm farm.”
Mr. Chambers’s two decades of investment in what he calls an
“underground movement” may be paying off. New research suggests that the
product whose manufacture he helped pioneer, a worm-created soil additive
called vermicompost, offers an array of benefits for plants — helping them grow
with more vigor, and making them more resistant to disease and insects, than
those grown with other types of composts and fertilizers.
The earthworm’s digestive process, it turns out, “is a
really nice incubator for microorganisms,” said Norman Q. Arancon, an assistant
professor of horticulture at the University of Hawaii at Hilo.
And these microbes, which multiply rapidly when they are
excreted, alter the ecosystem of the soil. Some make nitrogen more available to
plant roots, accounting for the increased growth. The high diversity and
numbers of microbes outperform those in the soil that cause disease.
By contrast, Dr. Arancon said, soil that has been heavily
exposed to synthetic fertilizers, pesticides and herbicides lacks microbial
richness and diversity, qualities that can be restored naturally by adding the
microbes from worms.
Some experts and entrepreneurs hope earthworms can also help
with another problem: the growing piles of animal waste from dairy farms and
other agricultural operations.
Worm Power, a company in Avon, N.Y., transforms 10 million
pounds of manure from a single dairy herd each year — about 40 percent of the
cattle’s output — into 2.5 million pounds of vermicompost. Tom Herlihy, a
former municipal waste engineer who founded the company in 2003, says it has
raised more than $6 million in venture capital and $2 million in grants for
research, much of it at Cornell University.
Here in Northern California, Mr. Chambers’s Sonoma Valley
Worm Farm produces about half a million pounds of similar compost, an amount he
plans to increase in the spring. He loads a long metal bin with cow manure and
300,000 to 400,000 Eisenia fetida, or red wigglers — weighing 300 to 400
pounds. In their wake, the worms leave cattle waste that has been processed
into rich and crumbly castings that look like fine peat moss.
It takes six months for a vermicompost bed to become fully
mature, by which time a million worms roam the manure. Mr. Chambers continues
to add two yards of manure and harvest one yard of worm compost weekly. The
finished product is shaved, an inch at a time, off the bottom of the bin. An
established bed can go on this way for years.
Both operations pre-compost their manure before they fork it
over to the worms. That means piling it up and allowing it to get naturally hot
enough to kill unwanted seeds and pathogens like E. coli.
The properties of worm compost are different from fertilizer
or manure. “It’s interesting and complicated,” said Rhonda Sherman, an
extension specialist at North Carolina State University who has taught
vermicomposting around the world for more than 30 years and who holds an annual
conference on the subject.
“Certain plants might react well to vermicompost from dairy
manure,” she said, “and other plants might react better to food-waste
vermicompost.” That has led to “boutique composting,” with different blends for
different kinds of plants.
A West Coast company, California Soils, uses worms to break
down cardboard waste fibers that are too short to be recycled. The glue used to
bind the paper serves as an important source of nitrogen for the worms. “It’s a
really good product for nut farmers and stone fruit farmers,” Mitch Davis, a
company spokesman, said of the compost, adding that it also helps control
nutgall, a fungal disease that afflicts walnut trees.
Worms were said to be Darwin’s favorite organism, and for
good reason: it seems they can break down most anything. Studies have shown
they can detoxify soil with cadmium, lead and other heavy metals.
Another product made from worm waste is a concentrate,
sometimes called tea, that Mr. Chambers extracts using an aerator. Dr. Arancon
said even a 1 percent solution of the extract had the same properties as vermicompost.
At Cornell, Eric Nelson, a plant pathologist, is studying
how compost suppresses disease. Worm Power’s product, he says, does a better
job than traditional compost, perhaps because the worm compost is highly
uniform. “The key is understanding why these microbes do what they do,” Dr.
Nelson said. Then, perhaps, the mechanism can be enhanced, he said.
The worm compost is considered valuable enough to fetch
almost 10 times the price of other composts.
Still, the industry suffers from image problems. “It’s hard
to bring it out of the ‘It’s cute to have a worm box in my backyard’ approach
and put it on par with other strategies for waste management,” said Allison
Jack, who earned her doctorate by studying vermicompost at Cornell and is now
teaching at Prescott College in Arizona.
The quality of products varies widely, and because there are
no industry standards, anyone can call a product vermicompost.
For a time, the worm business was a haven for swindlers.
Companies would sell worms to growers, who were told they could raise more
worms and produce vermicompost, which they could then sell back. Some of these
offers turned out to be Ponzi schemes.
Still, the properties of vermicompost have long been
recognized by growers. Jeff Dawson, the curator of gardens at the Round Pond
Estate winery in the Napa Valley, swears by Mr. Chambers’s castings, which he has
used for more than a decade.
“A cup or half a cup in the hole as we plant each vine
increases the vine’s ability to establish itself at a much faster pace,” Mr.
Dawson said. “And it creates a healthier plant.”
This being California, some of Mr. Chambers’s customers are
medical marijuana growers, and he likes the way growers do business. “They hand
you cash,” he said.
A version of this article appeared in print on January 1, 2013, on page D4 of the New York edition with the headline: Worms Produce Another Kind of Gold for Growers.
http://www.nytimes.com/2013/01/01/science/worms-produce-another-kind-of-gold-for-farmers.html
