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Thanks to [mread] I have been reading about the preColumbian civilizations of the Amazon (link). The soil in the Amazon is poor, but apparently in the lands inhabited by these ancients, they fortified the soil with charcoal. Just as charcoal filters absorb pollutants, the charcoaled soil retained
nutrients that would otherwise wash away, and was rich and fertile. _Is_ rich and fertile. The charcoal is there to this day.
I was initially surprised that charcoal does not break down but it makes sense. Pure carbon is a rarity in nature, and not many organisms are adapted to use it. Thus charcoal is carbon sequestered from the carbon cycle, just like limestone, even though it is right at the soil surface.
Charcoal is formed by the heating of wood in the absence of oxygen. I propose that the US construct immense charcoal factories, with rapid growing tree farms for the purpose of making charcoal. If scaled up,such an operation could compensate in part for CO2 emissions by burning fossil fuels. The carbon, now sequestered as charcoal, would be added to fields, increasing their ability to retain nutrients and thus decreasing fertilizer runoff and the problems with dead zones and algal overgrowth it causes.
I am not sure why wood is chiefly used to make charcoal. Probably because it forms convenient blocks. It seems to me that any cellulosic stuff should do the same - eg agricultural / yard waste, paper, etc. If trash could be fed into the charcoal factories, this would be a third benefit from this operation.
Precolumbian Amazonian civilizations.
http://news.mongaba...05/1017-amazon.html
See about halfway down for "terra preta" -the charcoal soil. [bungston, Nov 14 2005]
Landfill Gas
http://www.nstengin...om/Landfill_Gas.htm
[bungston, Oct 16 2006]
Terra preta resources
http://terrapreta.bioenergylists.org/
A good website with the latest developments [django, Sep 07 2007]
Biochar.org
http://www.biochar.org/joomla/
Biochar, agrichar, terra preta, carbon-negative bioenergy [django, Sep 07 2007]
Carbon-negative bio-energy production without environmental degradation
http://research.cal...ity?home=6&id=31058
Lehman, the scientist most active on this front, explains the simple principle [django, Sep 07 2007]
Carbon negative biofuels and biochar win UN World Environment Day Award
http://biopact.com/...ls-and-biochar.html
Actual field trials: tripled yields [django, Sep 07 2007]
Research confirms biochar in soils boosts crop yields
http://biopact.com/...ochar-in-soils.html
“When applied at 10t/ha, the biomass of wheat was tripled and of soybeans was more than doubled” [django, Sep 07 2007]
Wikipedia on pyrolysis
http://en.wikipedia.org/wiki/Pyrolysis
I wondered if this could be done at the dump. It looks like the answer is yes. [bungston, Sep 12 2007]
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Sensible idea for the right areas - I'm thinking this is much more sensible for the Amazon region, with its thin soils, but there are some parts of the States similarly afflicted. But is adopting the habits of our (distant) elders really a new idea? |
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The primary goal of this idea is to sequester carbon and combat global warming. This was not a concern of the precolumbians, I am pretty sure. The secondary goal is to decrease fertilizer runoff, which the Amazonians may have also desired - but because runoff is wasteful, not because they were concerned about aquatic ecosystems. |
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So: an old answer for some new problems. |
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I recently visited a landfill and saw how they reclaim "landfill gas". This is produced by anaerobic decomposition of carbon in the landfill. I think that the hot, anaerobic conditions in the landfill should also make a fair amount of charcoal. It may even be that plastics degrade into charcoal as well. The contents of modern landfills could be exhumed after the landfill gas output falls off, then used to amend fields. |
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Again: the rationale is to minimize fertilizer use by increasing soil carbon, which acts to store and slowly release fertilizers. |
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One would not want to grow vegetables in fields like this because of the potential for contamination of food crops by metals etc, and also sharp stuff like glass in the landfill that might hurt workers on foot. I could imagine machine-harvested fiber or fuel crops grown on such fields. One could also amend the soil after clearcutting to facilitate regrowth of forest. |
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I am thinking about this one again. Instead of charcoal, high sulfur coal could be used for the same application. I suspect it would work comparably well. This type of coal is less valuable given modern concerns about emissions. Also, there is a lot of coal already lying around which one could use. Coal dust would actually be ideal for this purpose, and I suspect is less ideal for burning. |
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Someone looking for a thesis at ag school could test the hypothesis, and probably get the coal donated. 2 test fields, one treated with coal powder before plowing and one not. Both are then fertilized. Which is more productive? Does this improvement carry into subsequent years? |
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What? A bungston idea that makes sense? |
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On the surface this looks like a fine idea. Especially with the use of field waste to produce the charcoal. (+) |
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So far as using coal, I think it would be much less effective. Much of the power of charcoal comes from its porous structure, which is lacking in coal. Also from its empty carbon bonds, which in high sulfur coal might be bonded with something like, oh, sulfur. (That last is a supposition.) |
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I am sure you are right. Lately I have been thinking chemical, not structural. |
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Could we use this to reclaim the Sahara? I am always looking for ways to do this. I think barren deserts are hideous wastes of a tropical zone. |
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If we could get some topsoil/grasses/trees going there, it would go a long way towards cutting our greenhouse gas imbalance, too. |
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Are you trying to get my goat, [GPL]? Because its too late, Nepal airlines already picked them up. |
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Why, do you have some attachment to the Sahara? |
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Not the Sahara in particular, but all deserts. They are extremely fragile ecosystems and we humans should leave them bloody well alone. |
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The Sonoran desert is beautiful. It is also chock-full of living things. |
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The Sahara? It's a giant litter box without even any cats. |
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Ostriches, Camels, Scorpions, Hyrax. All live in the sahara. And that is just the charismatic megafauna. |
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I bet all those things would love some grass to much on. |
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[+] This is being trialed on an increasingly large scale. |
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Bioenergy with biochar sequestration - the future of clean energy.
All other energy systems, including renewables such as solar or wind, are carbon positive. Biochar based bioenergy is carbon-negative. |
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If you use this energy, you effectively take *historic* CO2 emissions out of the atmosphere. |
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The UN will discuss ways to implement this on a global scale, at its next summit on Climate Change in Bali in December. |
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The best way to do this is to use pyrolysis: you get liquid biofuels from this and the carbon rich byproduct is stored in soils, boosting yields of your energy crops. |
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I can just picture the pastures full of peacefully grazing scorpions. Little boys and girls can act as scorpion herds, with little scorpion Shepard dogs to help them. At the end of the day they can herd them into barns for milking and making of scorpion cheese. Bucolic! |
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Do you think the ancestors of cows were friendly? |
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Considering that human action is largely responsible for the current size of the Sahara, I don't feel that there would be any particular harm in reclaiming some of it. |
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I am pretty stoked to see [django]'s
anno re biochar. The pyrolysis angle is
nifty too. I do not know what the
difference is between pyrolysis waste
and charcoal but I will dig around. |
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What would you use to heat the wood/trash/paper products in order to make the charcoal? |
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[quantum_flux]: as far as i understand it, when you heat the plant matter, many volatile compounds are driven off. these can be burned to run the cycle, leaving almost pure carbon behind. |
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I linked up wikipedia on pyrolysis. It is a good article and mentions the above application. I take full credit. But seriously, it looks to me like nearly 90% of material now going to landfill is carbonaceous and suitable for pyrolysis. The remainder is glass and metal. This could be removed with a screen after pyrolysis - the char remaining would work better in the soil if reduced to small particles, and the large particles remaining would contain the glass and metal. Pyrolysis to carbon would break down solvents and other matierals harmful to groundwater. Pyrolysis could sustain itself - bake the waste on gases generated by the waste. |
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Arguably this will generate more CO2 - otherwise this waste will go to a landfill, will it will break down slowly. However, the benefits from char in fields could be great, and improved crop yields will probably compensate for the CO2 produced by pyrolysis in a number of ways: more green matter incorporating CO2 and less fertilizer requirements. |
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This is a first world project. The massive industrial farms in the US would be amenable to treatment involving a minimum of different parties. If the char were delivered by the government and the farmers given a financial incentive to use it, it would happen. |
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