Wednesday, October 29, 2008

Biochar’s Fractal Dimension

In early September I traveled to Newcastle, England, to attend the second annual meeting of the International Biochar Initiative.

The conference drew together high ranking officials from the United Nations, international NGOs, appropriate technology experts from the developing world, commercial pyrolysis companies, foresters, agronomists, soil scientists, and others from 31 countries. We learned that you can actually make coal, carry it to Newcastle, and bury it in the ground, reversing the cycle begun by carbon-based capitalism 500 years ago.

Professor Tim Flannery told the gathering that even if we shut down every coal plant and stop all emissions of greenhouse gases from industry worldwide, the dangerous warming of our planet would continue for centuries. “That is the point at which you realize that biochar is really, really important,” he said.

Flannery suggested that 8 percent of CO2 is currently going into terrestrial vegetation, but if we could double that, we could buy ourselves time to work on moving away from coal and oil. Flannery said that we have to be mindful of the historic debt incurred by the one billion people whose ancestors made the industrial revolution. “That carbon debt to the other 6 billion could be repaid at 5 percent per year with biochar,” he said.

Johannes Lehmann (foreground) Tim Flannery (background) at IBI-2. Photo by Albert Bates, Farm News Service

Biochar production systems demonstrated at the conference turned up to half the carbon in biomass or waste product feedstocks into bio-energy — producer gas or wood vinegar — with the remainder captured as a dense, fine-grain, porous char.

This differs from other forms of biofuels in that the carbon is not returned to the atmosphere, either as carbon dioxide from burning, or as methane from decomposition. It is transformed into an inactive form that remains in the soil for thousands of years.

Mixed with compost and/or artificial fertilizer and applied as a soil amendment, biochar improves the tilth, water retention capacity, fertility, and carbon sequestration of degraded soils. Agricultural gains of 880% have been reported, according to Johannes Lehmann, soil scientist at Cornell and chair of IBI.

Scientific understanding of biochar began with the discovery of Terra Preta (“dark earth”) soils in Brazil in 1867. Subsequent surveys identified fertile islands of char-containing soils, corresponding to native settlements, dating back thousands of years, throughout the Amazon basin. At IBI-2 we learned that prehistoric Terra Preta has also been discovered in Australia and North America.

The carbon sequestration angle has brought the research effort greater urgency, and the International Biochar Initiative was formed to bring scientists, engineers, farmers, policymakers, funders and advocates into collaboration to speed studies, incentives and applications.

I’ll be blogging more about this in coming months, in part because we have been experimenting with biochar at the Institute for Appropriate Technology and are starting to get some interesting results, in part because skepticism is still warranted and biochar alone is not a solution for the existential threats we face, and also in part because we are engaged in a large-scale bamboo-to-biochar initiative that, if successful, will create the first permaculturally-designed biochar-based town -- 4500 completely carbon neutral homes near Chattanooga.

Mantria CEO Troy Wragg and his permaculture design team scout the best parts of a former Bowater pine plantation for places to plant the first bamboo groves. Photo by Albert Bates, Farm News Service

In a modern pyrolysis plant, 40% char yield is possible, with energy from the pyrolysis gases refluxed to burn cleanly and produce enough heat to drive the process, dry the feedstock and supply leftover power to a grid-intertie system. This makes about 4 or 5 bottom lines for biochar, and provides the first carbon negative power possibilities, including driving atmospheric carbon levels backwards to pre-Industrial Revolution levels on relatively short time frames. This is the basis of the process we have been advising on near Chattanooga, the small-scale kilns we are constructing at GVI, the subject of my workshop at the Ozark Area Community Conference 2 weeks ago and also one of my presentations at the financial permaculture course that concludes with a Farm tour later today.

What spurred me to pen my thoughts at this point was something Vandana Shiva said at a conference in Italy this past week. Real reform, she insisted, will happen when discussions move from the stratosphere to the soil, and when we find new, non-industrial ways of thinking.

The advantage that biochar offers is something similar to the advantage that fractal geometry conferred upon cell phone users a decade or more ago. The three dimensions of Euclidean space describe how most of us have been looking at the physical world for the past 2300 years. Einstein gave us a forth dimension, time, but it really only reinforced our “normal” way of relating to reality. It was still industrial thinking.

Mathematics has not been that static, and 4-dimensional, 5-dimensional, and even higher-dimensional spaces are now more than the stuff of shamanistic inquiry or surfer meditations. We have discovered fractal geometry in chaotic trajectories (strange attractors) and in natural systems (streambeds). It now seems possible that Euclid’s geometry was our limiting factor in understanding both why the polar ice and permafrost is disappearing as fast as it is and how to reverse the process.

Mandelbrot began his seminal treatise on fractal geometry by considering the question: "How long is the coast of Bretagne?" If you lay a ruler along a map of that coast, you get a rough approximation, but to get something more accurate, you have to use several smaller rulers, and as you do, the distance increases. Mandelbrot observed that eventually you will have to concede that if accuracy is your goal, the ruler gets diminishingly small, while the length of the coastline gets infinitely large. At some point even the concept of length becomes problematic.

Here are some graphical examples, all courtesy of Vanderbilt University. If you imagine the simplest ruler as the initiator, a next generation approximation of accuracy, called the generator, makes something mathematicians call the Koch curve.

The Koch curve takes each line and replaces it with four lines, each one-third the length of the original.

Do it again.

We do this iteratively ... without end.

A similar exercise is the Sierpinski Triangle. We start with an equilateral triangle, connect the mid-points of the three sides and remove the resulting inner triangle.

Iterating the first step we get:

The Sierpinski Triangle found its way to cell phones when engineers started experimenting with ways to shrink antenna size while not losing reception. They began with something that looked like a rat maze and before long had progressed into stacked pyramids.

Now they are imbedding fractal antennae into Kevlar helmets.

The advantage is not merely an increasing length for better reception, but the serendipitous discovery that frequency bandwidth is also improved, making many more channels possible. The helmet pattern demonstrates a very high gain antenna with a very small footprint.

Mandelbrot’s set is found by iterating
z n+1 = z n2 + c.
where z is a complex number. z0=0. When you do this, it is infinitely complex -- and it looks like mold.

What all this has to do with biochar is in how the Terra preta soils actually work their magic. One gram of biochar has a surface area of 1000 square meters. The way it accomplishes this is through micropores, the crystalline-like surfaces formed, randomly and chaotically, during pyrolysis. Terra preta’s carbon sequestration process uses a fractal dimension.

In the soil, biochar’s cavities fill up with nutrient foodstocks for microbes, much like a kitchen pantry. The microbes move in, and pretty soon hyphae of fungi appear. The hyphae are a fast road for nutrients and moisture – a trade exchange route to plant and tree roots. Examination of biochar-amended soils a few months after treatment found that vigorous fungal colonization was common.

If you can imagine the char as providing a coral reef-like structure, full of tiny polyps and crevices, it attracts all manner of soil organisms to it. If the pantry is empty, then those microbes will go to work to stock it, which is why biochar denitrifies over-fertilized, burned out farmland and replaces it with slow-release fertility, and also why “charging” the char with compost or urine before applying it is a good idea. I’ve got a charging station on the balcony just outside my bedroom door.

Urine passes through a spiraling tube from the funnel receptacle on the balcony to the char bin at ground level. Photos by Albert Bates, Farm News Service.

Not all char is char, as the saying in the biochar community goes. Imperfectly pyrolyzed, the char contains “activated” charcoal, that steals oxygen from the soil and releases carbon to fungi, microbes and plant roots and eventually back to the atmosphere, either as carbon dioxide, monoxide or as methane. With more careful pyrolysis, the carbon is locked tight and never leaves the soil. Biochar making, therefore, is not the same as charcoal making, and part of the concern is that if done poorly, the biochar revolution could actually add to our climate crisis.

Done well, the carbon becomes soil structure. The compost in its pantry becomes worm and insect castings, to be taken up by the tertiary decomposers that convert it into plant food. The whole process is supercharged by the fractal geometry, resulting in the observed gains unexplainable by any other means.

All of which is to say, Vandana Shiva is definitely onto something here.


Erich J. Knight said...

Charles Mann ("1491") in the Sept. National Geographic, has a wonderful soils article which places Terra Preta / Biochar soils center stage.
I think Biochar has climbed the pinnacle, the Combined English and other language circulation of NGM is nearly nine million monthly with more than fifty million readers monthly!
We need to encourage more coverage now, to ride Mann's coattails to public critical mass.

Please put this (soil) bug in your colleague's ears. These issues need to gain traction among all the various disciplines who have an iron in this fire.

I love the "MEGO" factor theme Mann built the story around. Lord... how I KNOW that reaction.

I like his characterization concerning the pot shards found in Terra Preta soils;

so filled with pottery - "It was as if the river's first inhabitants had
thrown a huge, rowdy frat party, smashing every plate in sight, then
buried the evidence."

A couple of researchers I was not aware of were quoted, and I'll be sending them posts about our Biochar group:

and data base;

I also have been trying to convince Michael Pollan ( NYT Food Columnist, Author ) to do a follow up story, with pleading emails to him

Since the NGM cover reads "WHERE FOOD BEGINS" , I thought this would be right down his alley and focus more attention on Mann's work.

I've admiried his ability since "Botany of Desire" to over come the "MEGO" factor (My Eyes Glaze Over) and make food & agriculture into page turners.

It's what Mann hasn't covered that I thought should interest any writer as a follow up article.

The Biochar provisions by Sen.Ken Salazar in the 07 farm bill,

Dr, James Hansen's Global warming solutions paper and letter to the G-8 conference last month, and coming article in Science,

The many new university programs & field studies, in temperate soils

Glomalin's role in soil tilth & Terra Preta,

The International Biochar Initiative Conference Sept 8 in New Castle;

Given the current "Crisis" atmosphere concerning energy, soil sustainability, food vs. Biofuels, and Climate Change what other subject addresses them all?

Biochar, the modern version of an ancient Amazonian agricultural practice called Terra Preta (black earth), is gaining widespread credibility as a way to address world hunger, climate change, rural poverty, deforestation, and energy shortages… SIMULTANEOUSLY!

This technology represents the most comprehensive, low cost, and productive approach to long term stewardship and sustainability.
Terra Preta Soils a process for Carbon Negative Bio fuels, massive Carbon sequestration,10X Lower Methane & N2O soil emissions, and 3X Fertility Too. Every 1 ton of Biomass yields 1/3 ton Charcoal for soil Sequestration.

Carbon to the Soil, the only ubiquitous and economic place to put it.

540 289 9750

Biochar Studies at ACS Huston meeting;



665 - III.


Most all this work corroborates char soil dynamics we have seen so far . The soil GHG emissions work showing increased CO2 , also speculates that this CO2 has to get through the hungry plants above before becoming a GHG.
The SOM, MYC& Microbes, N2O (soil structure), CH4 , nutrient holding , Nitrogen shock, humic compound conditioning, absorbing of herbicides all pretty much what we expected to hear.

Artemisa's Granddaughter said...

Very interesting, Albert. Thanks. Rough is real and good. Mandelbrot's critique of Euclid is elegant. Now we must do the same to Plato.

Jan Steinman said...

How much carbon is released in the manufacture of biochar and in the combustion of the resulting producer gas?

While biochar certainly saves more carbon than merely burning firewood, and I agree that its use as a soil amendment has value, it is not clear to me how it stuffs more carbon away than leaving the tree standing.

Albert Bates said...

Jan asks how much carbon is released in the manufacture of biochar and the answer to that is, it depends. Many things matter, including the temperature/pressure and duration of the burn, the control of oxygen, the feedstock and moisture.

As for how it stuffs more carbon away, I think we can empirically conclude from the carbon dating of terra preta soils in Brazil that it lasts twice as long as the oldest redwoods, and still going. Certainly some must be gnawed off and transported away every year, but by-and-large the terra preta soils do a better sequestration job than the trees above them. How that happens is a pulsing artery of scientific inquiry, but it may have to do with the distinction between "active" carbon molecules and "inactive" carbon, which is nearly pure C. The former can combine easily and be carried away, even to the atmosphere, while the latter remain as inert structure. What holds them so tightly bound? Is Buckytubes? We don't know yet, but we may some day.

Erich J. Knight said...

The modern Closed-loop pyrolysis units , like the companies below emit No GHG, the CO2 emitted when gas and oil are combusted is Carbon neutral.
Each fuel cycle for every ton of biomass processed sequesteres 1/3 as biochar


Anonymous said...

Could the charcoal that is left after a wood fire in a modern, efficient woodstove be crushed to make biochar?

Anonymous said...

I think the real question do you go about making biochar or buying biochar, and how do you apply this stuff?

Anonymous said...

Also, I'm not too sure what you meant with your comment here:

"As for how it stuffs more carbon away, I think we can empirically conclude from the carbon dating of terra preta soils in Brazil that it lasts twice as long as the oldest redwoods, and still going. Certainly some must be gnawed off and transported away every year, but by-and-large the terra preta soils do a better sequestration job than the trees above them."

From what I assumed about biochar, it allowed carbon sequestration by dramatically increasing plant yields by holding in nutrients and increasing microfauna, which in turn absorb more carbon and add to the carbon sink. I didn't have the impression that the biochar itself actually absorbed the carbon from the air

Anonymous said...

Why is activated carbon not sufficient for boosting soil fertility? If anything it would be even more porous than biochar wouldn't it? How much quicker would it degrade than biochar?

Albert Bates said...

I am grateful that there is so much interest in this posting. It is now 3 months later and we are still getting comments. I am resisting the impulse to reply to specific questions about biochar and the soil or climate because I am now working on a book for New Society on this subject and while I am learning a great deal more than I had known, it also is showing me how little I, or modern science, still knows. So until my book comes out and answers all your questions, I would just refer you to the lively discussions on numerous websites, and the terra preta list at

Ian Graham said...

If biochar is so hard to make properly, (as Bates reports), how is it the ancient Aztecs etc could do it?

Anonymous said...

time dimensions????

Webcatcher said...

On the 1st of August, 2009, Mantria Industries opened it’s Mantria EternaGreen Center at Dunlap, Tennessee. The facility is the world’s largest BioChar plant - and the only commercial operation of its kind anywhere.

The Center's output of BioChar can potentially sequester 96,000 tons of CO2 per year. The plant will convert 43,000 tons of biomass waste to 32,000 tons of EternaGreen™ BioChar annually. Additionally, the facility will produce enough BioElectricity to power more than 1,200 households.

In the fields next to the center, Mantria Industries will be growing bamboo, switch and elephant grass as feedstock for the plant, earning carbon credit in the process.

EternaGreen ™ BioChar is a BioProduct ™ created by the innovative EternaGreen ™ Carbonization process, which is a groundbreaking new method of converting biomass into energy, fuel and valuable carbon products.

BioChar itself is backed by over 30 years of research and promises to drastically reduce greenhouse gasses, increase crop yields greatly, and provides new life to our ecosystem.
As a soil amendment, EternaGreen TM BioChar can help increase the Cation Exchange Capacity or CEC which allows for nutrients to be readily available to plants. Due to its highly porous structure EternaGreen TM BioChar allows for supreme adsorption of nutrients, minerals, and gasses increasing microbial functions in the soil. EternaGreen TM BioChar acts as a "sponge" for nutrients and minerals releasing them as needed ensuring that farmers get the most out of your soil using far less water and fertilizer.

BioChar is not going to combat global warming alone, but will - now that it is available in commercial quantities - have a very positive impact on CO2 levels, green energy production, waste reduction and increased agricultural output.

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Anonymous said...

Please put this (soil) bug in your colleague's ears. These issues need to gain traction among all the various disciplines who have an iron in this fire.

new_biochar_land said...

You want to know all the secrets about biochar ?
This book will help !

Here practice and theory merge under a single cover of "The Biochar Revolution" and reveals hidden secrets of science called Biochar

Nicolás said...

I really enjoy your site and especially this article; this article helped me seal the deal and start making biochar here in Northern Peru...I dont know of anyone else doing it around here. Ive recently got my oven up and running, you can find it here:

I'd love some of you input or at least for you to check out our small effort at lending a helping hand down here.

Thanks and keep charring,


Erich J. Knight said...

Dear Nick,
Great work,
My only suggestion, in your text, is about char having "property of capturing atmospheric CO2".
Plants capture CO2, carbonization fixes that carbon plant cell structure to elemental carbon.

Buy burning only the hydro-carbon gas & oils, leaves the balance of the plant carbon to be returned to the soil.




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