One calculation by Robert Brown, director of the Office of Biorenewables Programs at Iowa State University, revealed that if the U.S. adopted a cap and trade program in CO2 emissions like the one already in place in the European Union, farmers in the Midwest could almost double their income by using corn stover—the leaves, stalks and cobs that remain after harvest—to fuel pyrolysis.
The use of char also promises to combat marine dead zones, like that in the Gulf of Mexico caused by nitrogen- and phosphorus-rich agricultural runoff. Char reduces the need for man-made fertilizers by helping the soil retain nutrients. In addition, it can be made out of the very same manure and sewage that would otherwise pollute the oceans.
Amazonian Origins
Agrichar is not a recent invention. Rather, it is a modern-day attempt to re-create the terra preta, or dark soils that cover some areas of the Brazilian Amazon. These soils were created over thousands of years by pre-Columbian Indians, who covered their fields with the charred remains of domestic and agricultural trash. This practice boosted the carbon content of the soils from a meager 0.5 percent to 9 percent.
"This is actually slash-and-char agriculture," Brown notes, contrasting it with the modern day slash-and-burn variety. "Instead of biomass being burnt down to a fine ash, charcoal remains, just like after a campfire." In addition to retaining nutrients, the porous charcoal helps microorganisms colonize and build up the soil. Charcoal is known for remaining stable over long periods of time, and alternating rainy and dry seasons preserve it even more. "You basically are drying out a steak," explains Danny Day, president of Eprida, a renewable energy development company based in Athens, Ga. "So you get beef jerky, which will last you for years." Even today, the Amazonian dark earths are so fertile that farmers continue to till them.
"What we're looking at is producing those kinds of charcoals in a modern pyrolysis reactor," notes Brown, who received a $1.8 million grant from the U.S. Department of Agriculture (USDA) to attempt to recreate terra preta using corn stalks. He plans to have enough char generated by this spring to run field trials this year. By his calculations each square mile of corn farm that uses this "fiber to fertilizer" pyrolysis process can offset the emissions of 330 automobiles.
But is it Viable?
As with all new technologies, many questions about the ultimate utility of agrichar have yet to be answered. "As of now agrichar is not a uniform product," explains John Kimble, a retired USDA soil scientist. "And there's no easy way for farmers to apply it with existing equipment. They also need to know there is a large enough source of the material. Farmers are driven by profit, as is everyone, and they need to be shown that it will improve their bottom line."
Complicating debates about the costs of agrichar is the paucity of data on the subject. "No one is sure what types of biomass should be used as raw material," Kimble notes, "or exactly what production methods work best, so calculating the costs is really an exercise in speculation."
In addition, scientists are finding it hard to replicate the original terra preta soils. "The secret of the terra preta is not only applying charcoal and chicken manure—there must be something else," says Bruno Glaser, a soil scientist at Bayreuth University in Germany. Field trials in Amazonia using charcoal with compost or chicken manure find that crop yields decline after the third or fourth harvest. "If you use terra preta you have sustaining yields more or less constantly year after year," he says.
"I'm skeptical about adding just a pure carbon source," says Stanley Buol, a professor emeritus from the Department of Soil Science at North Carolina State University's College of Agriculture and Life Sciences who spent 35 years studying Amazonian soils. "It will be black and look good," but will it contain enough inorganic ions, such as phosphorus and nitrogen, essential to plant growth?"
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9 Comments
Add CommentThe obvious near term solution would be to use the amazonian terra preta to inoculate the agrichar and other ingredients and grow it. I'm sure this has been tried and I'd love to know about results.
Reply | Report Abuse | Link to thisInoculation does indeed work in the Amazon, but not elsewhere. But why this is is the subject of much speculation. Unfortunately there is scant little research being done on the subject. It is soil that feeds us, but strangely the science of soil is underfunded throughout the World. For instance, we know very little about soil bacteria etc...
Reply | Report Abuse | Link to thisDear Ones
Reply | Report Abuse | Link to thisNew Exclusive Innovative Green Project, that will utilize the agrichar (renewable biomass waste) as a major raw material to produce light weight solid concrete bricks for the building &construction industry in order to substitute the widely used clay brick which should be prohibited since it is made on the account of our fertile land natural resources, mud/clay rich soil which should be conserved for only agriculture to cultivate more crops/food for a starving of food World.
When you have non farmers evaluating terra preta you miss the importance of the other materials present with charcoal, such as bones and fired clay bits (pottery and bricks) and wood ash. All of these buffer the acidic Latrelite soils, stablize the ionic clays and prevent leaching of the plant nutriants from the upper soil horizons. Because of the ionic buffering the water and nutriants in the soil are readily avaliable to the plants. Charcoal and pottery shards will survive for a very long time in latrelite soils that form in warm wet areas. These soils destroy organic humis very quickly and the clays cement up if exposed by tillage. The bones and wood ash balance the ph of the acid of the clay soils.
Reply | Report Abuse | Link to thisI am developing a project to produce biochar and biofuels from agave. One hectare of our ultra-high-density variety can produce from two hundred to five hundred tonnes of biomass per hectare per year.
Reply | Report Abuse | Link to thisWe are using several agave species, both for semiarid and temperater (Mediterranean) climates. We are developing cold resistant varieties.
Mainly, we will use the biofuels for electricity production -the main source of GHG in Mexico-, to mitigate emissions.
Regards,
Arturo Velez
agaveproject2@gmail.com
The Al Gore offer is for the sequestration of carbon dioxide (CO2). Has anyone noticed that this removes two parts of oxygen for each single part of carbon? What kind of scientists are working on removing this oxygen from our air? Bio-char is the only corrective carbon removal that I see right now.
Reply | Report Abuse | Link to thisWhat about the char produced from the pyrolysis of rubber and plastic? Can this also be added to soils?
Reply | Report Abuse | Link to thisno. the carbon from rubber produces carbon black and plastic produces coke. Neither healthy for soils, both with already large industries. essentially, they would poison the soil, very quickly making it toxic dirt. Carbon produced from fossil fuels (coal, tar sands, petroleum) contain way to many other toxics in it that would just not be cost effective to remove or filter out.
Reply | Report Abuse | Link to thisThe best source of biochar is woody mass... and at that, wood waste. Biomass across the board can go, but its actually the larger chunks (found in wood chips) that produces the best haven for microbial life and nutrient retention. Though... a mixture is still good..of small and large particles... both of which you find in larger wood chips. Smaller materials (leaves, grass clippings, etc) are better suited for composting... which, when blended with char, makes arguably the best soil this side of the equator (US).
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Reply | Report Abuse | Link to thishttp://biochar-books.com/
The Biochar Revolution collects the results and best practical advice that these entrepreneurs have to offer to the biochar community. When practice and theory advance to the point where they meet in the middle, then we will truly see a biochar revolution.