Biochar Soil Amendment: Miracle or Too Good to be True?

By P.J. Heller

Imagine a product that can, among other things, substantially improve soil quality, reduce nutrient runoff, offer huge productivity gains and provide a source of clean, renewable energy. And if that isn’t enough, how about if it could help combat climate change.

That’s the promise of biochar, a soil amendment that its proponents describe as “black gold” for agriculture, a “magic bullet” for the environment and a product that “has the potential to revolutionize the concepts of soil management.”

Critics, however, say there is little scientific proof of the claims, express concern that huge plantations will be needed to produce feedstocks for biochar utilizing massive amounts of land that could be better used for other purposes including food production, and that its carbon sequestration claims could be a “carbon time bomb.”
     “Large-scale support for biochar is premature and dangerous,” warns Almuth Ernsting, co-founder of Biofuelwatch in a statement in which 147 organizations worldwide described biochar as “a dangerous new false solution to climate change.”
     Even the most ardent advocates of biochar admit that more study and research needs to be conducted on the material. Standards for biochar are still being developed.
     “It’s very reasonable that folks are skeptical,” says Tripp Allen, president of Energy Anew in San Rafael, Calif., which manufactures and markets biochar under its “Biocharm” label. “They should be skeptical. We should approach biochar in a very reasoned and scientific way. I think we understand many of the benefits that biochar has on the soil. Some of the other benefits are not yet fully understood.
     “What I hope is that people will look into it further,” Allen says. “And once they look into further [they will see] it is completely reliable and the benefits can be demonstrated. So there isn’t a lot of smoke and mirrors.”
     Biochar, which is similar to charcoal, can be created from agricultural, farm or animal waste through gasification or pyrolysis, a form of incineration that chemically decomposes organic materials by heat in the absence of oxygen. Gases given off during the process can be a source of heat or energy.
     Based on the type of feedstock, as well as the time and temperature used to produce it, different types of biochar can be produced, according to its supporters. Work is under way on producing “designer” biochars targeted for specific soil types.
     For soil and compost producers, biochar could prove to a perfect amendment for their products, according to biochar enthusiasts.
     “From the studies we’ve seen so far, biochar performs much better as part of a soil management strategy,” says Thayer Tomlinson, a spokesperson for the International Biochar Initiative, a nonprofit organization with some 3,500 individual members worldwide. “If combined with fertilizer, compost or manure or whatever you put on soil, it can enhance the ability of the fertilizer or compost. It acts as an enhancer to that product.”
     Supporters of biochar point to “terra preta,” or black earth soil, in the Brazilian Amazon region, believed to have been created anywhere from 500 to 2,500 years ago through charred organic matter, such as animal waste and wood. Centuries later, they note, this soil remains much more fertile than surrounding native soils.
     After reading about terra preta about two years ago, Josiah Hunt became interested in biochar as a way to improve poor soil conditions on the Big Island in Hawaii. His company, Landscape Ecology, today is busy delivering truckloads of biochar — which he creates from scrap wood from area mills — to farms, landscapers and others on the island. He has even been asked to ship a container full of biochar to a customer in California.
     Hunt originally planned to sell biochar in a compost mix but was put off by the myriad state regulations on compost production. Instead, he blends about 1 to 2 percent of readily available and inexpensive fish meal with the biochar.
     “It really can in some cases have almost what appears to be a magic-bullet effect,” Hunt says. “Sometimes it is absolutely ridiculous the response that plants have when you add biochar.”
     Hunt agrees that incorporating biochar into everything from compost to fertilizer to soil mixes for potting plants can have highly beneficial effects.
     “I think incorporating small amounts of it into everything you do is the way to go,” he says. “I think it’s got so many possibilities to help improve these products. I don’t risk not using it. ”
     Allen, who has a degree in chemistry and has studied soil science, also became interested in biochar after reading about and visiting the Amazonian terra preta region. Tests he conducted growing five different types of vegetables in rich fertile Iowa soils (mollisols) with biochar resulted in a 25 percent to 35 percent increase in productivity, he reports.
     Allen says he was amazed by the results.
     “It was very difficult to believe,” he says. “Iowa soil is very high quality soil. So it didn’t make sense. I didn’t get it.”He also says tests of vitamins A, C and E in the vegetables, among them beans, radishes, lettuce and beets, showed “remarkable findings.”He plans to publish a paper revealing the results of his tests.
     Other tests he conducted in the clay soil of Marin County, Calif., also showed a “dramatic improvement” in productivity. He plans to conduct tests on other types of soils.
     To create his biochar, he uses wood chips in a blend with a high nutrient compost. One of the best ultimate uses for biochar or biochar blend is incorporating it directly into compost or a soil, he says.
     “We’re very interested in pursuing that as a market,” Allen says.
     “In my experience, there are not many soils that Biocharm doesn’t improve,” he says of his product. “I haven’t found one yet that it doesn’t improve.”
     Allen adds that soil blended with biochar is the ideal product for California growers who use containers to grow plants. He says some of those growers can “dramatically benefit” from biochar.

“Biochar and Biocharm is the perfect way to retain the high quality of the soil and, we believe, based on the studies we've done, it will increase vegetative growth and be able to get those container-grown plants to market faster,” he says. “Not only will it get them to market faster, but for those that sit around the soil will retain nutrients better and have a better shelf life. It’s particularly beneficial for plants that stay in the container for longer periods of time. For short periods of time, you’re basically gaining the benefits of increased vegetative growth.”
     Advocates also strongly tout biochar’s ability to fight global warming by sequestering carbon from the atmosphere in the ground.
     “The carbon in biochar resists degradation and can hold carbon in soils for hundreds to thousands of years,” according to the International Biochar Institute. Opponents say carbon sequestration in the ground could be eventually be released, in effect what they describe as “a carbon time bomb.”
     A research paper published in August said that greenhouse gas emissions could be reduced by 12 percent globally if every bit of biomass that could be collected sustainably was converted to biochar.
     “. . . If you were implementing biochar systems to mitigate climate change, would it be worth discussing it as a global strategy? Would it potentially scale to an important approach? The answer is yes," says Johannes Lehmann, a consultant on the study, an assistant professor of biogeochemistry in the department of crop and soil sciences at Cornell University and a board member of the biochar institute.
     Critics say such a plan would result in land conversions on an unprecedented scale with “plantations” devoted solely to growing feedstocks for biochar. Tomlinson of the biochar institute denies that would be the case and insists that smaller scale units would be more effective.
      “We have never advocated that plantations be used for biochar feedstock at all,” she says. “The large plantations probably wouldn’t be economically feasible to produce biochar right now.
     Tomlinson says her organization believes the best use would be to incorporate small scale systems into a community in a closed-loop system, taking wastes such as leftover agricultural waste, biomass waste products, poultry or dairy manure and possibly municipal solid waste, and using them for biochar production. The excess heat or energy generated from pyrolysis would be used to power other processes. The resulting biochar would be used on site.
     “There needs to be a real emphasis on the sustainability of the feedstocks and how the land is used to produce those feedstocks,” Tomlinson says.
     Critics contend that biochar advocates have masked their actual intent and that recent documents essentially call for “land grabs” on a massive scale.
     “They call for ‘sustainability standards’ but there can be nothing sustainable about converting lands on which millions of people depend and which are also important for ecosystem integrity and biodiversity protection,” says Raquel Nunez of the World Rainforest Movement.
     “Groups have been warning for years that the biochar techno-fix will mean land-grabbing on a vast scale,” adds Anne Maina of the African Diversity Network. “Time and time again, biochar advocates have misled the public with claims that we can produce vast amounts of charcoal from residues alone. Now they are showing their true colors: Large-scale biochar means large-scale land grabs.”

Hunt in Hawaii says he hopes more producers come online and that the product becomes more available, which be believes will help quell biochar opponents.

“I’m basically one of the larger producers in America and I’m one guy out of my backyard,” he says.

If and when biochar becomes more mainstream, “then you can start making a dent in the big picture items, more of the planetary issues, such as climate change and sequestering large amount of carbon,” Hunt says.

Allen, however, contends that the focus should not be about using biochar to fight climate change.

“I have to honestly say that I understand why people emphasize the issue of climate change for biochar,” he says. “In all likelihood, there’s no question that biochar is an excellent way to sequester carbon in the soil. But if you analyze the notion of using biochar as a mechanism for sequestering carbon solely, you’re missing the boat.

“The purpose of biochar is to improve plant growth,” Allen insists. “That’s the market that will drive biochar use because of improvements and reduced costs in agriculture. The notion that the market is going to drive biochar use from the standpoint of sequestering carbon I think is ridiculous. It’s never going to pay.

“The great thing about biochar is it’s one of the only things you can do on a very large scale . . . that gives you an immediate payback that is also really good for the environment."