Biochar: A ‘miracle product’ for amending soil?

An ancient, highly porous form of charcoal is being touted as a godsend for soil health and fertility – transforming farms, home gardens, and urban and suburban landscapes.

It might even combat climate change.

Any wonder they’re calling biochar a “miracle product”?

“It’s important not to promise too much, but this is mind-popping stuff,” says Dale Hendricks, owner of Green Light Plants, a wholesale organic nursery in Landenberg, Chester County, who talks up biochar to public gardens and local garden clubs, and cooks his own in barrels, kilns, and a wood stove.

finalproductsAlso known as soil carbon, biochar is made by burning organic crop, wood, and yard wastes, or manures, at very high temperatures and allowing it to decompose in the absence of oxygen, a process known as pyrolysis.

Mixed with compost and added to soil, it creates a coral-reef-style, carbonized skeleton underground that invites valuable microbial life and retains water, fertilizer, and nutrients. Most important from a global perspective, biochar takes carbon from the atmosphere and, rather than returning it in the form of carbon dioxide, stabilizes it underground.

Besides creating biochar, the pyrolysis process also retrieves valuable gases and liquids from the burning waste that could be used to replace fossil fuels.

Kelby Fite, a researcher for Bartlett Tree Experts, won’t go that far. But based on his own and others’ studies – and Bartlett’s “very, very positive” experience using biochar in residential and commercial landscapes in the United States, Canada, England, and Ireland since 2011 – he says, “I think the potential is huge.”

Others, like Przemyslaw Walczak, a horticulturist at Chanticleer, the public garden in Wayne, are more effusive.

Two years after adding the recommended 50-50 mix of “charged,” or aged, compost and biochar to Bell’s Woodland, a section of the 35-acre garden where compacted clay soil prevented anything from growing, he has a light, healthy soil and a frothy carpet of wildflowers in spring.

“Biochar was almost like a magical product,” says Walczak, who buys from Organic Mechanics, an organic-soil wholesaler in Modena, Chester County.

The Pennsylvania Horticultural Society uses the company’s biochar mix in a joint project with the city Water Department, called Rain Check, which helps homeowners manage storm water.

And last year, the University City District had success adding Organic Mechanics’ biochar “root packs” to its containers and public landscapes, including the Porch at 30th Street Station. All had suffered from extreme heat, poor soil, and car exhaust typical of dense urban neighborhoods, but rallied quickly with biochar.

The pre-measured packs – 12 for $24.95 – also contain organic fertilizer and nutrients and can be popped right into planting holes. “We love the stuff. We bought nearly 1,000 packs,” says landscape architect Nate Hommel, the district’s capital-projects manager.

No one loves biochar more than Jeff Wallin.

Since 2011, his Biochar Co. in Berwyn has been selling Soil Reef biochar products to everyone from homeowners, landscapers, and organic farmers to horticulturists, environmental conservationists, and commercial cannabis growers. With no advertising, sales have risen steadily throughout North America, including at select garden centers and Whole Foods markets in the Philadelphia area.

A one-cubic-foot bag of Soil Reef biochar soil mix costs $47.95, treats up to 24 square feet of garden space, and can last for years.

“But we don’t like it when people use words like magic and fairy dust and miracle,” Wallin says, “because it really is just basic chemistry . . . and science that has been rediscovered in our day and time.”

He refers to the centuries-old, unusually rich soils of the Amazon rain forest, which are known as terra preta or “black earth,” the result of adding burned plants to once-infertile soil. Japan, too, has a history of using rice-husk biochar to enrich soil.

Cornell University soil scientist Johannes Lehmann, a leader in the field, calls “quite astounding” the recent increase in biochar interest, scholarship, and entrepreneurship around the world. For all that, though, he suggests that more study is needed. The number of companies, products, and users is still small, and, based on current research, a true and complete assessment of biochar’s potential is not yet possible.

A 2013 study in the peer-reviewed online journal PLOS ONE considered the scientific literature on biochar through 2011 and found that only seven of 311 research papers had been conducted in the field, rather than a laboratory. And those seven estimated that biochar remained in the soil for 8.3 to 3,624 years – making it impossible to predict its potential impact on climate change.

“The studies we looked at didn’t give us confidence that all the hype around biochar is warranted,” says lead author Noel Gurwick, ecosystem scientist at the Smithsonian Environmental Research Center. “There are a lot of unknowns, especially about what happens to biochar over the long term in the real world.”

In the short term, Hendricks and others have discovered that the worse the soil – sandy, clay, depleted, compacted – the bigger the boost from biochar, a phenomenon that could have far-reaching implications, especially for poor nations around the world.

Hendricks’ soil has been enriched by years of organic practices, but he still cranks out the homemade biochar. He burns giant piles of cutup logs from cherry trees on his 12-acre property and scraps from woodworking friends, blends it with compost, lets it “charge” for at least a month, then adds it to his own plants or gives it away.

“There are lot of things we can do in the home landscape that are good-citizen things, besides driving smaller cars and having more garden and less lawn,” he says. “Biochar can be part of the solution.”

The article source: