this is getting interesting

China, Japan and Europe have already slowed down their population growth, now its up to the rest of the world to catch up. Clean energy is
the first way to a solution.

Terra Preta still is, I assert, unduplicatable, despite decades of work by at least one soil scientist. The modern pyrolysis technology was devised in part in an attempt to duplicate it. According to the review article, current thinking is that it takes 100 to 150 years for the fungi to do their thing. I agree that there are ’similar’ soils in Japan, but only similar. The only ’similar’ soils in Europe I know about are in the Ukraine, with deeply buried carbon horizons. Do you know of others?

A soil scientist at Cornell has measured the longevity, over a rather short period of time, of course. Your geologists firends are simply wrong, with regard to shallowly buried biochar used as a soil conditioner. Over the first few years about 1/2 re-enters the active carbon cycle. Otherwise, read the report regarding the preservation and non-preservation of charcoal in the ground. Basically, nobody is confident that the majority of it persists for more than a few thousand years.

Biocoal is formed via hydrothermal carbonization of the entire biomass. I posted links in my lengthy comment on the Hansen-350 thread a few back. Biocoal is exactly the same stuff, all ingredients, as high quality, metal-free, low-sulfur coal. Biochar, being formed by pyrolysis, is somewhat different. We know that biocoal will persist in the ground, buried at the same depths as coal in coal seams, because biocoal IS coal!

This deep sequestration is necessary because there is too much carbon in the active carbon cycle. Read the Hansen-350 thread. I’m not proposing a soil amendment, because the amount that needs to be sequestered is probably far more than farmers will want to put into their soils. Too much nitrogen harms most crops, and I assume the same will prove true of biochar.

I agree with your last paragraph completely. The use of charcoal just needs to be popularized. It is helpful to have a moble, modern pyrolysis unit, since biomass other than woody materials can be used and the machine produces valuable heating oils, but an old-fashioned charcoal burner will certainly get one started.

http://www.climos.com/climosblog/?p=25

“Terra Preta” appears to have no magical ingredients, no new elements specific to Amazon soils (which are ex-african dust anyway) it’s merely ground charcoal, manure, fish waste and several thousand years of colonization by microflora. If it wasn’t reproducible there wouldn’t be so damn much of it. The fact that similar soils were found in Europe and Japan testify that the concept is not unique just dormant.

As to the longevity, two PhD geologists I know have independently assured me that charcoal in soil is effectively there permanently. If it wasn’t there wouldn’t be any charcoal found in along with the proto-humans which is usually the case. Biochar once incorporated into soil is effectively a permanent sequestration.

You seem to prefer the creation and deep burial of “bio-coal” (which appears to be the same thing as bio-char) over agricultural use of charcoal. I’m not sure what the advantage would be since all evidence is that bio-char in an active root zone promotes the growth and sequestration of at least as much carbon as the contained in the original char. Why go to the bother of burning biomass just to bury a valuable soil amendment?

Finally the advantage of bio-char agriculture is that the required materials are a hoe, a machete and some land that will grow virtually anything else. Any 12 year old can understand the process and put it into place. Considering the surplus human population and the shortage of prime agricultural soils anything that sequesters carbon, improves soils and engages human labor all at the same time should be employed. No machines needed.

The currrenlty first paper up here:

http://terrapreta.bioenergylists.org/

by Dominic Woolf, surveys the current situation regarding biochar.

With regard to the question, “how much carbon do the farmers get to bury as char before it becomes geo-engineering?”, my answer is as much as they find it profitable to do so. If it becomes necessary to pay them to do it, then it is geo-engineering like any other farming subsidy.

If necessary to pay, then I prefer sequestering biocoal on a massive scale. The reason is that we know the biocoal, being coal, will stay in the ground for millions of years. There is no evidence that this is true for biochar, not even charcoal. (There is evidence that charcoal will persist that long in marine environments.) In any case, I posted a sketch of a plan regarding biocoal sequestration as a comment on the Hansen-350 thread.

If the results of early tests on adding bio-char to poor soils persist subsistance farmers will catch on and use the technique as soon as they understand it. The people in the Amazon cutting wood with stone axes and creating Terra Preta had to have profited from it or the practice would not have thrived.

So how much carbon do the farmers get to bury as char before it becomes geo-engineering?

I tend to think geo-engineering is (fatally) flawed on scientific (and practical) grounds. If I thought it would avoid catastrophic outcomes, rather than do nothing or make them more likely, I’d support it.

I don’t follow your question, tho. Cutting GHGs is mitigation.

Please restate it.