Terra Preta - The parent thread which started it all

[malcolmf]

Originally Posted by malcolmf

I'm thinking that there should be a code for terra preta makers

From what I've seen, terra preta nova makers need to be careful of their impact. Two kinds of impact:
- not having the intended effect (global warming mitigation and/or soil improvement);
- discrediting not only themselves but also the terra preta movement as a whole.

These are the rules I personally would observe:

I will ensure the regrowth of biomass to (at least) equal the quantity of feedstock that I use.
Otherwise there is no net reduction in atmospheric carbon.

I will not damage an existing carbon sink in order to obtain feedstock for char.
Otherwise I just rob Peter to pay Paul, or in this case to feed a pyromania habit. This limits feedstock to waste and purpose-grown biomass. But for example it is an incentive to keep hedges in trim and trees pruned.

I will not operate a charring process near habitation if it produces significant uncontained emissions of exhaust gases.
Otherwise emissions of CO2, CH4 especially, and N2O perhaps, will reduce or even negate the effect of removing carbon from the atmosphere. Furthermore, by not using gas feedback I roughly halve the efficiency of carbon fixation, thus wasting much of the feedstock. Not only that, emissions will quite literally get up the nose of the neighbours and, in sufficent quantity, would lead to a backlash against pyrolysis.

I will not damage an existing carbon sink in order to deposit char.
The same problem as robbing Peter above, but less obvious. If I disturb established covered land, such as pasture, to plough in char, I would destroy years of accumulated glomalin and subsurface biomass, and release their stored carbon through decomposition. A lot more carbon can be released than is added in the char.

I'm looking into one more, which is about how to manage the soil after adding carbon. Indications are that you should cover it with a mulch, use no-till methods (that is a la Rodale not a la genetically modified crops), and be careful about what else you add. Otherwise either the carbon will enter into reactions and not stay in the soil, or no glomalin will accumulate, or both.

Terra preta nova seems not to be the simple, magical solution that some recent articles portray. I am however struck by the idea that, while the rules might be hard on one person acting alone, they will be easier on a co-operating group or voluntary organisation, which should be able to muster the resources. Friends of the Earth (etc), are you with this yet?

M

[chrisbrandow]

so, perhaps someone should recommend Dr. Lehmann or others to apply for this new $25 million dollar prize for anyone with a reliable way to extract CO2 from the atmosphere. That is what TP does.

I can't link yet, but it is up on the nytimes home page. it is being sponsored by Richard branson.

[RBlack]

Chris, Thanks for the information. Here is the link to the Branson website with all the details about the contest/prize.

VIRGIN EARTH CHALLENGE

This is an exciting time to be involved in Terra Preta/Carbon research! A time where people are actually starting to care! A long ways to go still ... but a start!
RB

[erich]

In a message dated 2/9/2007 3:41:23 P.M. Eastern Standard Time, still.thinking at computare.org writes:
"I’m a bit incredulous Erich. I must be crazy, but I calculate the prize at ¼ cent per tonne removed. The price of charcoal will have to just a little lower that it is now to make the prize worthwhile. I guess if the world could be sold on Terra Preta the prize might be in reach.

If any idea is worthy it would be Terra Preta. Maybe the decedents of the ancient Amazonians should apply for the prize. If anyone else presents it Mr. Branson will likely just claim the idea has been around forever – or that you submitted it before the contest started and it is thus disqualified.

I guess Mr. Branson is just harvesting publicity and free advertising very cheaply. I understand the Brits are battling over aircraft emissions now.

It is amusing anyway."



Still.Thinking May have an Idea here. Maybe a petition to grant the prize posthumously to the original culture who invented it would , once Mr. Branson understood the modern potential, melt his heart and he could see an even more affective way to harvest "Green" publicity .

Just trying to still think too,

Erich

[malcolmf]

Originally Posted by erich

I calculate the prize at ¼ cent per tonne removed. The price of charcoal will have to just a little lower that it is now to make the prize worthwhile.

As I read it, the prize is for the greatness of the design, not for the tonnage removed. Saving the Earth is worthwhile.

M

[davidgmills]

Several pages back I posted my experiment to not extensively pulverize the charcoal I had bought from Cowboy Charcoal and just spade it into my garden using only a shovel.

I had wondered whether the Amazonians had gone to the trouble of meticulously grinding up their charcoal as it seemed highly labor intensive. Maybe they did not grind it up after all.

Just spading the charcoal into the ground seems to have worked fairly well. After a couple of months there are very few large pieces left.

Added a couple more bags today.

[Philip Small]

Fellow blogger, Back40, and I have been tossing out the potential glomalin link to TP function for awhile. I even emailed Dr. Lehman enthusiastically about glomalin a few weeks ago, thinking to pull my thoughts together on it for a blog post. He was not unaware of the rationale. His entirely neutral response reined me in a bit.

Since then my soil fungi:bacteria thinking has been highly stimulated by reading Jeff Lowenfels' "Teaming with Microbes" and it has hit me: it's got to be more complicated than just AMF kicking up their glomalin production. Maybe glomalin can account for the initial stages of transformation to TP, but there are pitfalls to fungi as an explanation for TP's self-replication once it has reached its full expression. By then the pH has come up, not so great for the fungi. By then the phosphorus levels have come up, not so great for mycorhhyzal mutualism.

The soils I see in the pictures of TP remind me of the types more conducive to high bacterial populations than fungal populations. If it is fungi, it would seem to be from a highly adapted fungal species. Perhaps, but could TP be an other-than-fungi/glomalin phenomenon? If so, we may be looking for a new recalcitrant organic carbon based substance in TP and an undiscovered pathway for its formation.

I think TP formation is driven by plant root exudates being delivered to grow microbial biomass, sequestering carbon pulled from the air. The fungi-like bacteria, actinomycetes, seems a candidate. Next I would consider the archeae. And because it is soil, the reality here has the potential to be deliciously nonlinear, multi-staged, complex and inter-connected.

[malcolmf]

Originally Posted by davidgmills

I had wondered whether the Amazonians had gone to the trouble of meticulously grinding up their charcoal as it seemed highly labor intensive. Maybe they did not grind it up after all.

You are right, David, they didn't. Nor did they bother spading it in. Recent thinking (Lehmann et al's Amazonian Dark Earths) is that Terra Preta, black earth, accumulated from burned waste from cooking fires and trash heaps around habitation, while Terra Mulata, brown earth, accumulated from in-field burning. TP may even have been made unintentionally, though personally I doubt that would have been true for very long once they saw what it did. TM seems to have been intentional: see previous post with evidence from Hecht & Posey on sophisticated uses of fire and mulching in present-day Amazonian agriculture, though this may not be precisely the same management regime as in the past. TM carries just as much carbon, but less phosphorus and calcium, which are what give TP extra fertility.

I'm not sure that we can hope to mimic the Amerindians exactly if we want quick results. But nor am I sure that going for quick results will achieve anything worthwhile. Are you regrowing the char you use? Has it simply been taken from a living carbon sink? Has your digging destroyed more soil carbon than you put in? Are you protecting the carbon so it does not decay?

We should all by looking for ways to answer these questions rightly. For the first, very cheap and IMHO worthwhile tree planting to replace char is available at the Oxfam Unwrapped site (click on Gifts That Grow). Still time to give as a Valentine's Day gift, though she might not think it very romantic

M

[davidgmills]

Making your own charcoal and terra preta.

Before I found lump charcoal from Lowe's, ( I now buy Cowboy Charcoal, see

: Cowboy Charcoal Co. )

I made my own.

I suggest everyone do it at least once or twice as it is very safe IF YOU DO NOT MAKE IT IN YOUR HOUSE!

YOU MUST MAKE IT OUTDOORS. YES YOU WILL POLLUTE THE NEIGHBORHOOD WITH YOUR SMOKE, SO BEWARE, BUT NO MORESO THAN IF YOU WERE BARBECUING. The smoke just won't have the aroma of a barbecue. It will smell like smoke.

The principle is very simple. You are going to roast the wood just like you would roast a chicken. You do not want the wood to catch on fire anymore than you would want your chicken to catch on fire.

Roasting the wood drives off three things, in order of lowest temperature: water, gases, oils. The water, gases, and oils are what we call smoke.

When the water is burning off at the beginning of the process, the smoke will look gray or white. When the gases burn off near the middle of the process, the smoke begins to yellow. When the oils burn off towards the end of the process, the smoke turns blue. When it quits smoking altogether, you have charcoal!

Here is the most efficient method I found for urban use. I started with a small popcorn can about 2 and 1/2 gallons. It must have a lid. A galvanized trash can with a lid would be great, but I could not find one to buy. So would a 55 gallon drum with a lid.

In the bottom of the can start a small raging fire. Once the fire is going good, put in just enough lump sized pieces of wood to extinguish the flames but still leave the wood smoldering. From here on out you will be roasting the wood, not burning it. Branches 1 to 2 inches in diameter and cut to 3 inches or so in length are perfect to make "lump" charcoal. Slowly fill up the can with the "lumps" of wood keeping the wood smoldering at all times. Once the can is filled up, loosely put on the lid, leaving a crack between the lid and the sides of the can (usually about 1/2 to 1 inch) to let the smoke out. DO NOT LET THE WOOD IGNITE. The lid is necessary to keep the wood oxygen starved so that it smokes not ignites. REMEMBER YOU WANT TO ROAST THE WOOD, NOT BURN IT!

When you are done, if the lump charcoal tinkles like a wind chime, you have made it right. If not, you probably didn't cook it long enough, or overcooked it.

The process, which seems to waste the least amount of stock, takes a coupe of hours depending upon how much stock you begin with. When the process quits smoking, you have charcoal. Put on the lid tightly and extinguish the fire. About 1/3 of the stock you started with will be charcoal.

Once the process is complete and the charcoal lumps are completly extinguished, pulverize the lumps (I use a pair of pliers) and put the charcoal particles in your garden. Mix thoroughly with the soil.

The first year, you must kick start the terra preta process with fertilizers, because the charcoal has not yet had the ability to filter out of the air or rain water, any nutrients for the plants and bacteria. The bacteria which thrive in the charcoal have a symbiotic relationship with the root hairs of plants and they are constantly taking the nutrients captured by the charcoal to the plant roots.

You are done. Welcome to the new world of terra preta.

Now feel very good about yourself!

Oh, and feel free to make a claim for some of Al Gore's and Richard Branson's prize money. You have earned it.

[Philip Small]

Originally Posted by malcolmf

Has it simply been taken from a living carbon sink?

True that. From a recalcitrance perspective, converting a living carbon sink to a charcoal sink is a good thing only if that charcoal ends up in the soil (versus under the BBQ). A net increase in soil charcoal levels world wide is more effective at global cooling than the same net increase in lignin because charcoal is more recalcitrant.

From a carbon sink dynamics perspective, converting a living carbon sink to a soil charcoal sink is a good thing. The living carbon sink functions to convert atmospheric CO2 to carbohydrates. Stimulating this rate capacity is fundamental to the attraction of biochar/agrichar utilization.

I find these two perspectives compelling but am concerned that it doesn't account for the relative impact on climate change of the differences in N20, CH4 and CO2 generated from the lignin breakdown versus pyrolysis: charcoal production can produce high levels of N2O under some, but not all, scenarios. N2O is potent greenhouse gas. Any scheme to produce agrichar should address the N2O production involved. High nitrogen content biomass increases N2O, as does lowering the temperature of pyrolysis. I expect (need to know more) that utilizing the wood gas for fuel can eliminate the N2O load to the atmosphere. How we make the biochar and what we do with the biogas are both as important as what we do with the biochar.

Note: the solar charcoal production mentioned earlier in this thread seems to produce CH4, but did not mention N2O. I would like more information in that regard.