Ancient South American powdered charcoal method could well revolutionise modern farming

[phloom]

Here some really interesting articles....

http://www.bidstrup.com/carbon.htm

http://terrapreta.bioenergylists.org/bestUNaward

Edited June 6, 2007 by phloom

[Anodyne]

Interesting indeed. I skimmed sections, but I don't think it said - would grey/white ash be good too?

[paradox]

hey man, i didn't fully read your articles there but i saw this on a doco once.

it's really F awsome, there are all these little patches of ultra fertile ground in the amazon like 100 m square & a few metres thick. supposedly they were where certain indians were living ages ago. they mine out tons of this super fertile soil & just leave a thin layer of the stuff there, then a few years later they come back & the ultra fertile soil has "grown" back, like whatever constituents which are resposible for the ultra fertility grow & spread into the soil once again. then the process is repeated.

f incredible!

[nabraxas]

^ i saw that doco too. it was pretty amazing.

the dark fertile soil is called "terra preta".

Here's the wiki entry:

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

[paradox]

so this is how they reckon it "grows" & spreads. where would we be without fungi ay:

"Amending soil with low temperature charcoal produced from a mix of wood and leafy biomass (termed biochar) has been observed to increase the activity of arbuscular mycorrhizal fungi. It is theorized that terra preta self-propagates via this mechanism; a virtuous cycle established as the fungus spreads from the charcoal, fixing additional carbon and stabilizing the soil with glomalin, and increasing nutrient availability for nearby plants".

[ThunderIdeal]

first up, glomalin sounds like it might be one of the main reasons that fungal decay is more beneficial to soil structure than bacterial decay, but the wiki entry for it doesn't actually say that. it does say:

"Glomalin is causing a complete reexamination of what makes up soil organic matter. It is increasingly being included in studies of carbon storage and soil quality."

second, i got the impression from the wiki entry that this is the kind of thing anybody could practice, almost anywhere. even though the terra preta contains pottery, fish bones etc etc, it is basically just the result of "slash-and-char", the same thing as slash and burn but at lower temperatures. it does not say how they kept the temperatures lower.

however, the longer article had a different explanation..?

it basically said that the mineral content of the terra preta is identical to the surrounding infertile soils, except for the presence of very fine particles of (manually ground) charcoal, up to 40% of the soil. the fine charcoal, with it's trapped, heat-stabilised plant resins, act as colloids, storing plant nutrients and also capturing nutrients that float by in the ground water, trapping them for centuries (whereas in the poor structured soil, free nutrients would be washed out by tropical rain). symbiotic BACTERIA in the root hair zone of TERRA PRETA PLANTS free the nutrients in exchange for nourishment from the plants.

maybe both explanations are significant, but the second may be dependent on plant species and the presence of those bacteria in order to be useful.

thirdly, the wiki entry gives reason to believe that amazon people were once populous and more agrarian, reverting to nomadic lifestyles (and slash and burn) after they were invaded.

around ten percent of the land contains terra preta and the terra preta can be 10 percent broken pottery!! which seems to indicate that large populations were practicing the slash-and-char technique.

however it gets me thinking... maybe these large populations would char wood and leaf from SURROUNDING areas then carry the product into the terra preta areas, which would account for the striking distinction in fertility. that's a different scenario to the one you saw on the doco, paradox, but i just made it up.

the juries out on this one, for me. it would be good to have a definite, agreeable explanation. it's nice to think maybe there is an equivalent to humus which can be created just by charring vegetation and grinding it up. the second definition describes the charcoal dust as having that kind of an effect on soil structure, maybe with a different pattern of nutrient release to humus though. i interpret the first explanation as more a case of large amounts of fungal organic matter (particularly this glomalin stuff which is abundant on the hyphae and spores of arbuscular mycorrhiza).

this is very promising for the recovery of soils everywhere. it sounds like there is still more to be learned about this. the least we could do is get more of a solid picture of what is currently known.

Edited June 9, 2007 by ThunderIdeal

[ThunderIdeal]

i'm going to start by pasting some bits in here, out of context, but they will be linked. some of the stuff i've found is very relevant.

http://transectpoints.blogspot.com/2007/02...ades-terra.html

"He did get excellent plant growth responses to adding biochar - as long as mineral fertilizer was also used. When you look at plant growth in the biochar only treatment, growth was worse than doing nothing at all (check plots). In the nutrient-poor and highly leached soils of the tropics, the added biochar likely bound whatever nutrients were present in the soil solution and these became unavailable for plant uptake. These results should make you cautious as well. How fertile a soil needs to be for biochar not to reduce plant growth or exactly how much fertilizer and/or compost should be added to be sure there is good, sustained release of nutrients, will likely vary soil to soil and we simply do not have these data available at present to make proper recommendations. So, keep this in mind as you do your own trials with your own soils or mixes. Try to follow good design practices for your trials, with replicates, so that you can judge for yourself what amount and type of biochar works best in combination with what amounts and types of fertilizers or composts you use (depending on the philosophy behind your cultural practices)."

Actinomycetes bacteria seem to have a particular affinity for terra preta.

"Brendan found that populations of culturable bacteria and fungi are higher in the terra preta soils, as compared to the unmodified soils, in all cases. Yet, Biqing found that the respiratory activity of these populations is lower (see Liang et al., 2006), even when fresh organic matter is added. This alone means that the turnover of organic matter is slower in the terra preta soils - suggesting that the presence of black C in the terra pretas is helping to stabilize labile organic matter and is itself not turning over in the short term. All good news for C sequestration. However, since the respiratory activity is lower (slower decomposition), this may lead to slower release of other mineral nutrient associated with the fresh organic inputs. In some circumstances this is a good thing (maintaining nutrient release over the growing season), in other circumstances (more immobilization), perhaps not. We need more work on this"

mention of a possible innoculant for tfuture use with biochar

"So far, what we know is that both bacterial and fungal communities differ strongly between the terra pretas and the unmodified soils, but that the populations are similar between the terra preta soils. These results are both interesting and encouraging. First, that the terra preta soils (sampled from sites many kilometers apart) are more similar to each other than to their closest unmodified soil (sampled within 500 m) tells us that the conditions in the terra pretas encourage the colonization of these soils by similar groups of organisms that are adapted them. Our group has been working on cloning and sequencing both isolates from the terra preta soils and DNA extracted directly from them. A number of bacteria that were isolated only from the terra preta soils are related to the actinomycetes, but have not yet been described yet and are not very closely related to other sequences of known organisms in the public genetic databases. This is also very interesting. Some of you will know that actinomycetes have many unusual metabolic capabilities and can degrade a very wide range of substrates. Also, many are thermophilic and play important roles in the composting process. We have yet to fully characterize these organisms, but are optimistic that in time we can make some recommendations about what organisms or combinations of organisms might make a good inoculant for container-based biochar use."

this stuff was written in february... surely some more info has come out. help me find it!

"I want to add a word of caution about getting too excited about glomalin. Another of my students, Daniel Clune, has been working on this topic and his work suggests that the glycoprotein referred to as 'glomalin' in the literature - operationally defined as the protein extractable in a citrate buffer with repeated autoclaving - is not what it has been purported to be. First, the proteins extractable by this method are from a wide range of sources, not just arbuscular mycorrhizal fungi. Second, it has a shorter turnover time than has been suggested. Third, in a test with hundreds of samples taken from field trials varying in age from 7 to 12 to 34 years, its relationship with aggregate stability is suggestive at best. Dan's work is also being written up right now and should also be submitted for publication soon."

http://forums.hypography.com/terra-preta/3...ted-all-38.html

TM = terra mulata, 'brown earth', perhaps the product of in field burning or some less intensive process than that involved with TP

1. Charcoal massively increases AMF growth, and is used extensively for this purpose in Japan. E.g. Saito & Marumoto (2002) 'Inoculation with arbuscular mycorrhizal fungi: the status quo in Japan and the future prospects', Plant and Soil 244(1-2), pp. 273-279.

2. AMF inherently produce copious amounts of glomalin (Driver et al (2005) 'Characterization of glomalin as a hyphal wall component of arbuscular mycorrhizal fungi', Soil Biology & Biochemistry 37(1), pp. 101-106). This glomalin is recalcitrant and persists long after the hyphae have died.

3. AMF are ubiquitous and are productive in tropical forest soil (Lovelock et al (2004) 'Soil stocks of glomalin produced by arbuscular mycorrhizal fungi across a tropical rain forest landscape', Journal of Ecology 92, pp. 278-287).

4. Fire does not reduce AMF the way it does other fungi, leaving them as the dominant group for up to 15 years after a burn (Treseder et al (2004) 'Relationships among fires, fungi, and soil dynamics in Alaskan Boreal Forests', Ecological Applications 14(6), pp. 1826-1838). Terra preta soils were prabably continually burned during formation (Hecht in Amazonian Dark Earths).

5. Glomalin forms water-stable soil aggregates (Rillig et al (2002) 'The role of arbuscular mycorrhizal fungi and glomalin in soil aggregation: comparing effects of five plant species', Plant and Soil 238(2), pp. 325-333).

6. Water-stable aggregates of a similar size to those characteristic of glomalin bind and protect soil components (Teixera & Martins in Amazonian Dark Earths). This accounts for many of the properties of Dark Earth soils: stability; water retention; carbon retention; nutrient retention and reduced leaching; reduced CH4 and N2O emissions.

Perhaps you have heard of Occam’s Razor, or of Einstein’s “smallest possible number of hypotheses”? The important properties of terra preta do not need bacteria to explain them. Bacteria work with AMF (Rillig et al (2006) 'Phylogeny of arbuscular mycorrhizal fungi predicts community composition of symbiosis-associated bacteria', Fems Microbiology Ecology 57(3), pp. 389-395), so as you say the reality will be found to be nonlinear, multi-staged, complex and inter-connected, but they aren’t needed as independent agents.

Quote:

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.

Self-replication of terra preta is reported by Amerindians but is there any scientific evidence for it? It seems to be one of several questionable beliefs (German in Amazonian Dark Earths), in this case perhaps based on Dark Earth’s rapid recuperation under fallowing. Another such belief is that TP does not lose fertility or break down. It most definitely does if not maintained properly (German again).

pH up? The mean pH of terra preta is 5.7, and of terra mulata 5.3 (Kämpf et al in Amazonian Dark Earths), higher than the awful common soil but nowhere near suppressing fungi.

Phosphorus up? The high P (and Ca) levels in terra preta are believed to be original, from the debris of habitation, not accumulated. They are reported to be the main features distinguishing terra preta from terra mulata, apart from the colour, which is probably due to bacterial decomposition of the debris but has no known beneficial effects. Terra mulata has low P and shows that P does not “come up” in Dark Earths. A useful hypothesis: more glomalin will be found in TM than in TP.

http://forums.hypography.com/terra-preta/1...s-tp-303-a.html

I very much agree with your post above and feel that formation of humus, humin, glomalin, and other stable soil organic material may be what makes Terra Preta. What drives Terra Preta is the adsorption properties of charcoal/carbon and the physical structure that charcoal gives to the soil for microbes, and soil structure and texture. The adsorption properties act as a "bank" that keeps most everything that goes into the soil and everything that happens in the soil around for use and reuse. If you have enough positive conditions (air, water, SOM, microbes, nutrients, CEC, good parent minerals), then you get formation of stable SOM. Once you have a good amount of stable SOM then this drives the system even more by being both a catalyst for creating positive soil conditions and a repository for nutrients and minerals. At some point you get the right mix of charcoal, stable SOM, and microbial life that creates the self sustaining system we call Terra Preta. That may be why Amazonian farmers say that Terra Preta grows back and why in the hot and high rain environment of the Amazon that Terra Preta has persisted.

well solid answers don't seem to be out there yet, but it's something i'd like to dedicate some time in personal research to, if i had some land (and time). maybe commercial techniques and innoculants will appear in future, although specific use of this idea will probably have to vary from place to place.

[phloom]

Im glad there's some here looking seriosly at this, apologies for the short and superficial replies.

Some interesting points made by Crucibal Carbon in an address to parliament about carbon capture with AgriChar;

http://www.dpmc.gov.au/emissionstrading/su...ionstrading.pdf

- Pyrolised charcoal sequesters carbon without oxygen long term, unlike cabon capture from fossil fuel plants which sequester more oxygen than C.

- It can be made using biogas produced by the material itself, so is self sufficient in energy demand, a closed system ie doesnt require fossil fuel energy input.

- "Australia's large land mass, high solar energy exposure, low rainfall and low carbon & saline/marginal soils mean that mega tonnages of this long life form of carbon could be sequestered for hundreds or thousands of years by enabling large scale biomass to biochar processes. That biomass will be purpose grown algae & land crops, and farm, forest & other wastes. Non potable/saline water could be used."

Very interesting indeed!

Surely this breed of technique will be much cheaper than the symptomatic ones such as carbon capture?

Edited June 11, 2007 by phloom

[ThunderIdeal]

i'm personally interested in the horticultural/agricultural implications, but using it to sequester carbon is probably much more important for the world and everyone.

does this mean that any woody or leafy mass that isn't going to be used should be charred rather than allowed to decompose? plants sequester carbon, but if they decay then it goes back into the world, if they're just burned then it mostly goes back into the world.

i'm still unsure as to how charring and grinding material compares with decaying it, as far as soil improvement goes, so maybe sequestering is the only real gem that is going to come from this anyway, apart from maybe providing an initial boost to certain soil life and symbiotes.