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Home, Garden, and Car Care Special Section The Altamont Enterprise, October 8, 2009

A world movement in your own backyard

By Philippa Stasiuk

VOORHEESVILLE — How do you bridge the gap between thinking globally and acting locally?

On Sept. 15, David Yarrow, a longtime grassroots activist from Syracuse, spoke to a crowd at the Cornell Cooperative Extension about something that may make local gardeners part of an international accelerating movement: biochar.

Biochar is a fine-grained porous charcoal made from biological material through pyrolysis, or low-oxygen burning, that is high in organic carbon. Making biochar is basically making charcoal.  But the kicker comes when it’s used in the garden.

“When you add charcoal to the soil, it changes the soil dramatically,” said Yarrow. “The soil becomes nutrient dense. The charcoal absorbs water and nutrients and, with this kind of fully fertile soil, you can grow food that has complete nutrition.”

That may sound like another overblown advertisement in the back of a horticulture magazine, but the Internet is rife with websites of not-for-profits, science symposiums, and early published scientific results on biochar’s potential.

The Biochar Fund, based in Belgium, just published its results on Sept. 10 on a field test in Cameroon where 1,500 subsistence farmers participated in a study where biochar was mixed into the soil of the yearly corn crop. The farmers with biochar soil yielded between 40 to 50 percent greater biomass than the farmers without it. Other studies around the world have shown that while adding biochar alone does not increase crop yields significantly, adding biochar plus fertilizer increases yields by up to 50 percent.

Scientists have been able to measure soil improvement with biochar in four ways. First, it increases the cation exchange capacity (CEC) in soils, which is a measurement of soil fertility and its ability to protect groundwater. Char is also porous, which means that microbes in the soil attach to it like water to a sponge, and are less easily washed away by rainfall. This also ultimately makes the soil nutrient dense.  

The char is itself also retains water, which means less water evaporates and less irrigation is needed if rainfall is light. Finally, biochar increases the pH of acidic soils, similar to the addition of lime to soil.

Local and global activism

Scientists, politicians and not-for-profits see potential for biochar to address issues like world hunger, erosion, and water quality.

But, in addition to improving soil and subsequently food, biochar has another quality that is tantalizing scientists: It is carbon negative. In contrast to fossil fuels, which add carbon to the air, biochar retains a substantial portion of the carbon in the soil where it stays for potentially thousands of years. The result is less carbon dioxide in the atmosphere. With such prospects, scientists and businesses are in a race to find out if biochar could be applied to reducing carbon emissions on a large scale and how to go about it. 

Again, the global applications are many. At the September North American Biochar Conference in Colorado, which Yarrow attended, ideas such as specifically plowing land for biochar as a way to reduce significant amounts of earth-warming carbon were discussed. Carbon-producing companies could also buy pyrolytic stoves for individual farmers who would produce biochar in a sort of carbon exchange.

But focusing on sequestering carbon, says Yarrow, is the wrong way to think about biochar’s potential. “At the national conferences, everybody is talking about sequestering carbon,” he said. “No one is paying attention to the sterilization of the soil, which is a fundamental living component of the planet. If done properly, biochar will restore living tissue to the soil. It needs to be rejuvenated and revived in order to stabilize the atmosphere, to make a future.”

Yarrow explained that it is gratifying to see peoples’ reactions to his talks on biochar. “I get excited because it won’t be governments and corporations that get us out of this mess,” he said. “It will be the power of the people to make choices at the cash register and the voting booth.”

Making biochar

Part of Yarrow’s lectures on biochar includes a demonstration burn. While there are already pyrolitic stoves being developed and sold around the world, it is also possible to make a burner with refitted barrels of two different sizes, such as a 30- and 50-gallon barrel.

While Yarrow’s website shows the exact method, the process basically entails filling the smaller barrel with biomass, such as wood or corn stover, covering it with the bigger barrel, and turning them upside down so that the biomass burns with a minimal amount of carbon dioxide. The space between the two barrels is filled with wood and, in less than two hours, biochar can be produced. A photo account of the process can be found on Yarrow’s website: http://www.carbon-negative.us under “burners.”

Joseph Slezak, the Albany County field manager for soil and water conservation, attended Yarrow’s lecture in Voorheesville and spoke about its local applications.

“It’s something that anybody that lives outside a suburban area, the Hilltowns mostly, as long as people can burn outdoors, they can create biochar and put it in their home gardens, he said. “If they can cooperate with other neighbors, they can do it on a larger scale and use it for agriculture fields. There’s potential.  I don’t think enough people know about it yet.”

Slezak also said that the composting facilities in the Capital District could benefit if they diverted some of the biomass used for composting towards biochar, which could then be used by local gardeners to improve soil quality.

Yarrow said that, while new ideas generally take 50 years to be adopted by large populations, the urgency of global warming and biochar’s potential role in helping to curb carbon-dioxide emissions is speeding things up.

“It’s a new idea that is skyrocketing,” said Yarrow. “Now science is on our side, maybe things can happen quicker.”

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