This article has me thinking of the incredible potential for biochar. This is a must read for gardeners and do-it-yourselfers.
A world movement in your own backyard
By Philippa Stasiuk, The Altamont Enterprise, October 8, 2009
www.carbon-negative.us/
VOORHEESVILLE, NY—How do you bridge the gap between thinking and acting locally?
Sept. 15, David Yarrow, a longtime grassroots activist from Syracuse, spoke to a crowd at Cornell Cooperative Extension about something that may make local gardeners part of an accelerating international 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 I 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, in Belgium, published results Sept. 10 of a field test in Cameroon where 1,500 subsistence farmers participated in a study of yearly corn crop. Farmers with biochar soil yielded 40 to 50 percent greater biomass than farmers without it. Other studies around the world have shown that while adding biochar alone doesn’t increase crop yields significantly, adding biochar plus fertilizer increases yields up to 50 percent.
Scientists measure soil improvement with biochar in four ways. First, it increases cation exchange capacity (CEC) in soils, which measures soil fertility and its ability to protect groundwater. Char is also porous, so that microbes in soil attach to it like water to a sponge, and are less easily washed away by rainfall. This ultimately makes the soil nutrient dense.
Char also retains water, which means less water evaporates and less irrigation is needed. Finally, biochar increases the pH of acidic soils, similar to addition of lime to soil.
Local and global activism
Science, politics and not-for-profits see biochar’s potential to address issues like world hunger, erosion, water quality.
But, in addition to improving soil and subsequently food, biochar has another property 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 potentially for thousands of years. The result is less carbon dioxide in the atmosphere. With such prospects, science and business racing to find out if biochar can reduce carbon levels on a large scale, and how to go about it.
Again, global applications are many. At the August North American Biochar Conference in Colorado, which Yarrow attended, ideas such as specially plowing biochar into soil to reduce significant earth-warming carbon were discussed. Carbon-producing companies can buy pyrolytic stoves for farmers, who can produce biochar in a carbon exchange,
But sequestering carbon, says Yarrow, is not the way to think about biochar’s potential. “At the national conference, everyone talked about sequestering carbon,” he said. “No one pays attention to the sterilization of soil, which is a fundamental living component of the planet. Done properly, biochar will restore this living tissue that is soil. It needs to be rejuventated and revived to stabilize the atmosphere, to make a future.”
Yarrow explained that it is gratifying to see peoples’ reaction 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 biochar talk includes a demonstration burn. While there are already pyrolytic 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 30- and 50-gallon barrels.
Yarrow’s website shows the exact method, which entails filling a smaller barrel with biomass, such as wood or corn stover, cover it with a bigger barrel, and turn them upside down. Space between the two barrels is filled with wood, so the biomass burns with minimal oxygen. In less than two hours, biochar is made.
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 anybody that lives outside a suburban area—the Hilltowns, mostly—as long as people can burn outdoors, they can create biochar to put in their gardens,” he said. “They can cooperate with neighbors to do it on large scale, for agricultural fields. There’s potential. Enough people don’t know about it yet.”
Slezak also said composting facilities in the Capital District can benefit if they divert some biomass used for composting to biochar, which is used by local gardeners to improve soil quality.
Yarrow said new ideas generally take 50 years to be adopted by large populations, but the urgency of global warming and biochar’s potential to curb carbon-dioxide 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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