Make Biochar — this Ancient Technique Will Improve Your Soil

If you're interested, I just posted the results of my experiment growing winter squash in a pit burned using basic biochar techniques. See it here:

http://www.compostgardening.com/moreinnovativemethods/biocharvlayeredcrater.html

Sorry about the multiple posts, maybe admin can remove them for us? The end of the post was cut off so..

However The USEPA has offered a lifetime cancer risk estimate of 62 per 100000 exposed people per µg benzene emission per m3 ambient air from burning, with incomplete combusion producing the highest levels of the most dangerous PAH. The guidelines values for Benzo(a)Pyrene corresponding to an excess lifetime cancer risk of 10-5 was estimated as 0.7mg/litre in Guideline for drinking water quality (WHO, 1998).

The comment about charcoal removing lead is not correct and lead is rarely in a bioavailable form in non tropical temperate zone soils where the soil geochemistry in any case, unless it is associated with the breakdown products of leaded gasoline from leaking underground tanks of former gas stations.

I am a director of science of an environmental consultancy with a special interest in PAH. I hope that you find this helpful and that it encourages you do do some reading of your own. I think you will be shocked.

The incomplete combustion of organic matter produces extremely toxic polycyclic aromatic hydrocarbons, (PAH), which have no place in agricultural soils.

These compounds are so dangerous that some of the partial burn products such as pyrene are regulated here in Europe to the point that the presence of ANY of these proven carcinogenic toxins above laboratory detectable levels, (in some cases just a few parts per million), triggers the legal requirement to clean the land up to remove PAH or remove the pathway between the compound and humans.

The presence of these compounds will also mean that in the UK, where the values exceed our soil guideline values, then the soil contaminated with levels of PAH easily exceeded by this proposed process would actually be classified as hazardous waste and have to be sent to a special landfill or treated to remove the PAH contamination.

Also, PAH contamination of groundwater is a serious problem in much of the industrialised world.

I would not want to see farmland polluted in this way. Also, given the probable increase in N2O output from treated soils and the release of CH4, (nitrous oxide and methane, both many time more powerful greenhouse gasses), I doubt that there are any net benefits overall in the release of greenhouse gasses.

It is good to see alternative ideas and thinking about how we can do better, but this has to be properly thought about. I for one would not eat any food laced with PAH.

Much as I dislike wikipedia, a good introduction to the chemistry of PAH can be found here

http://en.wikipedia.org/wiki/Polycyclic_aromatic_hydrocarbon

Owing to its carcinogenic properties no safe level of PAHs can be recommended. There is no known cancer threshold for Benzo(a)Pyrene the most thoroughly studied PAH. (World Health Organisation, 1987). All levels are associated with increased cancer risk

However The USEPA has offered a lifetime cancer risk estimate of 62 per 100000 exposed people per µg benzene em

I have an outdoor wood stove that heats my home. I am going to start a vegetable garden this season and was wondering if ashes from my stove would provide good soil amendment for my garden? Any thoughts about doing this?

We have just started selling a precharged biochar product for gardeners in Marin County California called Growth Charm. Biochar such an important thing to do for so many reasons. Reducing the use of fertilizers and improving soils nutrient holding capacity are well known. Few seem to appreciate biochar's ability to protect food crops from soil toxins including allelopathic chemicals from certain trees like black walnut and even charcoal's ability to extract and hold lead so that plants don't take it up.

From a reader:
The sentence about making charcoal from wood scraps in metal barrels should have been followed immediately by a very strong caution not to use wood that has been treated with chemicals to retard rot and/or insects. Inhaling smoke is very hazardous to health. Each piece of new stock treated wood has a caution not to burn stapled onto one or both ends
- Mother

Barbara,
Thank you for your comments and suggestions. I may bring this up at our local fish club as a possible project also.
Thank You again,
Chris

My family burns corn for heat in the winter. I wondered if the waste from the corn stove would be suitable for use as biochar. Does anyone know if this is so?

Carolyn,
Your alkaline conditions would benefit more from using woody materials as mulches or soil amendments than from burning them, and I agree with your agent about the wood ashes. Woody materials in general have an acidic pH, which is exactly what you want. Mulch and compost is the way to go. Good luck...

Chris,
One of the leading researchers at Lehmann's lab at Cornell also keeps fish, and uses her old charcoal in soil mixes for houseplants. I think you do have a valuable resource! If I had your scummy activated charcoal, I'd rinse out salts and then mix it with finished compost that's being set aside to cure. Or, just dump it in your garden. My I suggest keeping track of its possible effects? Lots of people would like to know more about its value in the garden.

I have a question. I raise tropical fish and use activated charcoal as a filtration agent. Would this work as Biochar after its effectiveness as a filter medium? I already use some waste water from my tanks for my container garden and wonder if I am throwing out a valuable resource. Any thoughts?

The pH of my soil ranges from 8.0 (in the garden) to 8.5 (on my lawn). My county agent has told me not to add ashes to my soil because ashes will raise the pH. What is the pH of biochar? Can I just shred material with a high carbon content and bury it, or does it really need to be burned first?

Bio Char is great stuff , but as with anything else it can be overdone. Keep in mind that the nutrients in the char do add to the total nutrient ballance in the soil. To much of a good thing is seldom good.

About global warming or Global Climate Change as it has morfed to since things have started to cool off, you are not going to save the planet with bio-char. You can improve your soil and the quality of your food a lot if done in moderation.

As we crusade to "save the planet " from the CO2 monster, just remember that your house, your wood table, the trees, your garden and almost everthing you have ever eaten was once free CO2 floating around in the atmosphere. Yes, it all came out of the air.

I have asked a lot of CO2 Chicken Littles what is the Ideal PPM of CO2 we are targeting and "NO ONE" knows! Would the climate adjusting God like person who is capable of knowing this and managing the climate please step forward and present their credentials. Careful though, a false prophet with a good line of BS and an ego to match could cause unbelivable dammage while making themselves rich beyond immagination.

Didn't the Goracle make just over 100 million selling carbon indulgence thus far. May need to get some of those before starting up the char pit.

It is so great to have so many sharp minds weighing in on biochar. There is much to think about, both globally and at home. The latter is my specialty, and we gardeners have an opportunity to look not only at how biochar might benefit our soils when used as an amendment, but also at the effects of on-site burning on the soil itself.

It is possible that as low-oxygen burning takes place IN the ground, soil biota respond by staging a wave of renewal that is somehow captured and slowed by biochar. But there is much we don’t know. As I researched biochar for the article, I kept coming back to mental pictures of the early agricultural society that created terra preta. Archaeologists think they enjoyed a lot of leisure time. When a crop did come in that required hard work, the people probably moved to the field and turned harvesting into a party. For example, cassava (also called manioc or yucca) was dug, stripped, cooked and dried in the field, over a period of days. Replicating that process means burying the fire, which is why I started with an excavated site.

Please join me in thinking up ways we can make or use biochar in our gardens without releasing unnecessary smoke. To show you more of my experiment, we added some photos to this article’s IMAGE GALLERY today. Other staffers at Mother Earth News will be trying their ideas, too, but the proof will be in our gardens. Stay tuned!

Thanks for helping us think big, and in this case, thanks for helping us think small, too.

Great article! I had never realized the connection. We have an open burning law in my city so it's kind of frowned on to make fires in town. But the idea of checking campgrounds is great. There are actually a couple of close state camping grounds within driving distance!
Nice article, great information with a huge impact for us all!

i thought this was a great article. But I was wondering how much biochar was enough and can you get too much in a garden. Also how fine should the charcoal be when it is applied to the soil.

Whoa. Biochar is a great thing, but let's not get carried away. Read page 3 of this article again carefully. When you make biochar you release a lot of CO2 into the atmosphere -- just not as much as open-burning of wood with unrestricted oxygen produces, but you're still putting out plenty of CO2 into the air. You only make up for that when you put the biochar into the garden and it does its job in the soil over decades. So it takes a long time before the making of biochar becomes "carbon neutral" if it ever does. Certainly making biochar will do nothing to reduce or "balance out" the amount of carbon going into the atmosphere from other sources such as autos and coal-fired power plants as one reader seemed to be suggesting.

I thought Barbara's comments on biochar were almost perfect. I say "almost" hoping there can be more next time on the climate benefits of biochar - a topic that is driving many Mother Earth readers to this magazine. If we all (6.5 billion) were to produce just a ton of biochar each year, we could offset our entire annual global atmospheric input of fossil fuel-based carbon. Of course most of us will have to rely on the local utility or biofuels suppliers to do much of that on our behalf.
But as Barbara has demonstrated, we can have better gardens if we do more ourselves as well. In addition to the two very different charcoal production techniques offered by Barbara and the blacksmith - let me recommend closing down one's wood burning stove each night. I am now getting about a pound or two of nice cold lump charcoal each morning. Granted the room temperature drops a bit lower - but I am getting more into home gardening as I try to lower my carbon footprint through biochar - that I have to put somewhere.

For those who don't have open ground where they can make biochar -- and those who live where open burning is prohibited -- what about something as simple as using a stand-alone BBQ grill (the kind intended for Sunday grilling which are allowed everywhere)? Branches and other scrounged wood/weeds, even a bag of coarse "pine chip" mulch from the garden center, etc. could be control-burned in the grill. BBQ grills have a built devices for controlling the amount of oxygen that can get to the fire. While probably not as good as the retort kiln mentioned in a previous comment, it certainly seems like a viable way to create modest amounts of biochar -- and a new, round BBQ grill can be had for as little as $20 bucks in a Mega Mart or Big Lot store.

Interesting article, but I live in the city and open burning is illegal. I'm thinking Lump Charcoal might be a good alternative. It's generally charred hardwood, (molding cutoffs and other hardwood scraps) unlike charcoal briquettes which can contain coal, petroleum byproducts and starches which act as binders.
I'm involved with competition BBQ. The cooks who don't use wood pellets use either Lump Charcoal or wood chunks, so you might look into cleaning up behind a competition near you.

The charring methods described in the article are certainly not environmentally friendly, sonce smoke from charring contains methane, PAH and othe nastiness. Use a retort kiln instead. They are really simple.
See http://www.holon.se/folke/carbon/simplechar/simplechar.shtml
Lots of other methods to burn the fumes during charring exists. See for example the Anila!
FG

I hear of this biochar and it seems great.

I worry about adding heavy metals to the soil.

But the point I wanted to ask was whether this is a case where the by product of "wood gas" or heating a biomass without oxygen and capturing the volatile gases.

Those volatile gases can be used to produce electricity and the "charcoal" that is the by product could be added to the soil!!

It bothers me when a "Green" approach is not a "Wholistic" approach.

That is a really good artical, but would regular chacrol, like the kind we use for grilling work in the same manner, even it it's been used like ashes?

I would like more specifics, please. How deep does the trench need to be, and how high can I pile the organic material (above the top of the trench?)? I will be digging through clay and shale, so I need a specific depth to work towards.

I also have been corresponding with Michael Pollan ( NYT Food Columnist, Author ) to do a follow up story.
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.
It's what Mann hasn't covered that I thought should interest any writer as a follow up article;

Biochar data base;
http://terrapreta.bioenergylists.org/?q=node

NASA's Dr. James Hansen Global warming solutions paper and letter to the G-8 conference, placing Biochar / Land management the central technology for carbon negative energy systems.
http://arxiv.org/ftp/arxiv/papers/0804/0804.1126.pdf

The many new university programs & field studies, in temperate soils; Cornell, ISU, U of H, U of GA, Virginia Tech, JMU, New Zealand and Australia.

Glomalin's role in soil tilth, fertility & basis for the soil food web in Terra Preta soils.

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

This is a Nano technology for the soil that represents the most comprehensive, low cost, and productive approach to long term stewardship and sustainability.

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

In a recent National Public Radio interview, Michael Pollan talks about how he was approached by a Democratic party staffer about his New York Times article, The "Farmer & Chief", an open letter to the next president concerning U.S. agriculture/energy policy. The staffer wanted Pollan to summarize the article into a page or two to get it into the hands of Barack Obama. Pollan declined, saying that if he could have said everything that needed to be said in two pages, he wouldn't have written 8000 words.

Michael Pollan is well briefed about Biochar technology, but did not include it in his "Farmer & Chief" article to Pr

I thought these updates and endorsements may interest you,

Senator / Secretary of Interior Ken Salazar has done the most to nurse this biofuels system in his Biochar provisions in the 07 & 08 farm bill,
http://www.biochar-international.org/newinformationevents/newlegislation.html

Below are my current news & Links to major developments;

Cheers,
Erich J. Knight
540 289 9750

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!

The IBI Announces Success in Having Biochar Considered as a Climate Change Mitigation and Adaptation Tool;

POZNAN, Poland, December 10, 2008 - The International Biochar Initiative (IBI) announces that the United Nations Convention to Combat Desertification (UNCCD) has submitted a proposal to include biochar as a mitigation and adaptation technology to be considered in the post-2012-Copenhagen agenda of the UN Framework Convention on Climate Change (UNFCCC). A copy of the proposal is posted on the IBI website at
The International Biochar Initiative (IBI).

Modern Pyrolysis of biomass is 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, Bio-Gas & Bio-oil fuels, so is a totally virtuous, carbon negative energy cycle.

Charles Mann ("1491") in the Sept. National Geographic has a wonderful soils article which places Terra Preta / Biochar soils center stage.

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.
http://ngm.nationalgeographic.com/2008/09/soil/mann-text

I also have been corresponding with Michael Pollan ( NYT Food C