Terra preta For newbies

[Michaelangelica]

A very good clear well written, introductory web article on the major ideas of Terra Preta

 

You might want to use it so you can convince the neighbours that you are not crackers grinding up, running the car over, burning, burying; good BBQ charcoal. :evil:

http://www.championtrees.org/topsoil/TerraPreta.htm

[Michaelangelica]

Another introductory article on Terra preta (TP)

He does the sums on carbon sequestration (ie How to reduce global warming. I can't say I really followed that bit- but I failed maths)

Saving The Planet While Saving The Farm: How soil carbonization could save the planet while it makes farming profitable again

Apparently, the indigenous farmers of the region had taken to carbonizing their farm waste, grinding the charcoal to a fine powder, and adding it to the soil. The richest soil samples, those with the greatest fertility, were between nine and forty percent charcoal by volume, and the charcoal was powdered to a fine powder - a few hundred microns was the average particle size. There are few bits of charcoal any larger than a quarter of an inch in size. The charcoal was produced in a low-temperature process, not heating it too excessively. It contained within its molecular structure plant resins that had been heat stabilized by the pyrolization process.

 

Because nobody had ever bothered to investigate powdered charcoal's effects on soil fertility carefully, soil scientists had simply always assumed that charcoal when added to the soil, was inert and its effects primarily mechanical. Chemically, it is very stable at ambient temperature - even on geological time scales - and does not participate in chemical reactions, so it was simply assumed that any nutrients it trapped were simply unavailable to plants. Close investigation of the terra preta situation proved this to not be the case. Not at all.

. . .

What the soil scientists, working with microbiologists, discovered was that a community of bacteria exists in symbiosis with the root hairs of plants in terra preta soils. The bacteria produce enzymes that release the mineral ions trapped by the heat stabilized plant resins in the charcoal and make it available to the root hairs of the plant as nutrients. In return, the plants secrete nourishment for the bacteria.

Not only that, but the resins within the charcoal act like an ion exchange resin, adsorbing traces of mineral ions onto the charcoal particle surfaces from the rain water, and trapping it within the charcoal's molecular structure, where it can be held for centuries - until the soil bacteria associated with a root hair come along and secrete the enzymes necessary for it to be released once again. So the trace minerals always present in rainwater actually act as a fertilizer - providing the nutrients needed by the crops, year after year.

The secret of the soil fertility of the terra preta was finally understood. And it was understood how the indigenous farmers were able to produce bumper crops year after year, decade after decade without a single application of chemical fertilizer and without wearing out the soil.

Saving The Planet While Saving The Farm: How soil carbonization could save the planet while it makes farming profitable again

[Michaelangelica]

A German article kindly translated for us by eric1

 

 

 

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Translation - Today, 01:16 AM

I tried to insert the translations between the pragraphs, but this made the message too long for posting. So I have to leave you with the translation and some titles alone

 

Never to fertilize any more owing to the black earth of the Amazonas

 

The black earth from the rain forest of the Amazonas makes plants in home and garden grow faster and stronger, and on top of that renews itself almost automatically

 

Voices on the subject

ZDF-Reportage 2003

ZDF-report 2003 (ZDF = Zweites Deutsches Fernsehen = second German (public) television network)

Marc van Roosmalen, Feldforscher am Rio Aripuana, über die Folgen konventioneller Bewirtschaftung:

Marc van Roosmaalen, field researcher on the Rio Aripuana, about the results of conventional management.

 

“The Indios have started with Terra Preta in order to be able to go on living for generations on the same land – without burning as is done these days. Now the farmers cut now fields from the rainforest again and again, cultivate on them for some few years and next have to cut down a new field, leaving the soil unfertile.

Wit hall our modern chain saws and axes we can not live as well in tune with nature – as could the allegedly primitive Indios of the past.”

 

Marc van Roosmalen advises the use of Terra Preta for cleansing the rain forests:

 

“Terra Preta can change the future of the rain forest. When one knows hoi t is made, one can foroce the people to contrive their fields on Terra Preta like the Indians. Then they would need only a small piece of land, that would have tob e cleared only once and covered with Terra Preta.

Next one could work it for generations, without having to burn down more sections of the rain forest.”

Ein Bauer zum Thema:

A farmer on the subject :

 

For years, Damiäo has been cultivating coffee, papaya and other tropical fruits on the abandonned Indio fields – easily recognized by their black earth, the so called Terra Preta. Again and again, Damiäo discovers remnants of the Indio culture. He shows van Roosmalen an Indio oven, in which there is still a bread, possibly more than a hundred years old.. It is covered with a thin coat of tree rubber, and was surrounded by Terra Preta, the “black earth”. More and more scientists discover proofs of a highly developped Indo culture that confirm at last the reports of Francisco de Orellanas from the 16th century.

 

With a sample of the soil from Damiaös plantation, Marc van Roosmalen wants to determine the thickness, the age and the exact composition of the Indio soil Terra Preta. Soil experts have confirmed meanwhile that the Indios, using a mixture of molusc chalk and charred tropical wood, achieved a small miracle : a soil that is not washed out by rainy seasons.

The Indios could remain in the same loction for 2000 years. Now their fields are worked by de Caboclos, many of them for over 40 years completely without fertilizing.

Universität Bayreuth, 2002

Dipl. geogr. Gerhard Bechtold:

Geography grad. Gerhard Bechthold

:

Terra Preta (do indio) is a black earth-like anthropogenic soil with enhanced fertility due to high levels of soil organic matter (SOM) and nutrients such as nitrogen, phosphorus, potassium, and calcium embedded in a landscape of infertile soils (see soil profiles below). Terra Preta soils occur in small patches averaging 20 ha, but 350 ha sites have also been reported.

These partly over 2000 years old man made soils occur in the Brazilian Amazon basin and other regions of South America such as Ecuador and Peru but also in Western Africa (Benin, Liberia) and in the savannas of South Africa.

Terra Preta soils are very popularby the local farmers and are used especially to produce cash crops such as papaya and mango, which grow about three times as rapid as on surrounding infertile soils.

(I am not going to translate this back into German – not even if you ask for it !!!)

Arte TV 2005

Arte TV 2005

Terra Preta: Das schwarze Gold des Amazonas, eine Dokumentation von Peter Adler

Terra Preta : the black gold of the Amazonas, a documentary by Peter Adler.

 

Untill recently, the “green hell” along the largest hydrographic system of our planet, was considered was considered tob e unstirred for thousands of years. But not far away from Manaus, a metropolis in the Amazon area, Brazilian archeologist Eduardo Naves discoverd artefacts and fragments, obviosly relics from an early civilisation.

A memory of cities and empires that have l disappeared long ago ? Neves and his American colleague Jim Petersen believe they have struck on remnants of large villages in the surrounding forest.

 

 

The “Terra Preta do Indio” black soil lies like small islands in the otherwise extremely unfertile amazon area. Everywhere where the rain forest is burnt down, the ashes allow for a short time of aggriculture.

 

But the soil is washed out soon, and the farmers can not afford costly fertilizers. Instead they burn down new sections of the forest, in a diabolic spiral.

 

 

Agronomists and soil experts are sure that “Terra Preta” is man made, but how ? That is why the “Terra Preta Nova”-project is about, on which scoentists all over the world are contributing in different fields of testing.

 

By combined fertilizing with charcoal, biomass and compost an originally unfertile soil can be made into a flowering landscape, and allow for the economical development of poor areas, at the same time preventing further destruction of the rain forest.

[mjodvis]

I have a couple of questions about terra preta that I'm posting on the newbie site since I definitely fall under that category. Hopefully, neither question is too naïve. My apologies if these questions have been answered elsewhere.

 

1. I've read numerous places about the remarkable (indefinite?) amount of time that charcoal will remain sequestered in the soil, continuing to replenish soil nutrients with microbial help. This got me thinking about the effects that earthworms might have on the amount of charcoal in the soil. Are there any data on earthworm consumption of charcoal in the soil? And, if so, does the charcoal become something else after passing through an earthworm, or is it still charcoal?

 

2. On another terra preta thread I read about how the pottery shards in the soil appeared to be made with a type of sponge that provided the pottery with tiny silica tubes or microfilaments that enhanced certain kinds of microbial activity (that was my understanding of it at least.) Have there been any studies on attempting to use plants with a high silica content, such as horsetails (equisetum), as a source of biochar or compost in modern terra preta experiments? I imagine that the silica in such plants would not be in the correct microtubule form, but then again, my knowledge of biochemistry is pretty minimal.

 

Thanks for any elucidation.

 

mjodvis

[erics2112]

I've got a friend looking for a pyrolysis unit to produce agrichar to replace his current stove that he uses to heat a greenhouse. Where can one be found? Or plans for building one?

 

TIA - Eric

[Philip Small]

I've got a friend looking for a pyrolysis unit to produce agrichar to replace his current stove that he uses to heat a greenhouse. Where can one be found? Or plans for building one?

 

TIA - Eric

 

I believe the solution is simply an airtight stove with either a catalytic converter or an optimized design.

 

An airtight stove restricts airflow sufficiently to support pyrolysis. It will have a sealed firebox and tight fitting door. It will have a manually operated or thermostatically controlled air-intake damper to allow air to circulate around the firebox and to control the rate of fuel consumption. It provides slow-burning heat for a long period with relatively little attention. Shutdown before the burn is complete will yield charcoal.

 

Because the airtight stove is slow burning, it may not ignite the wood gas generated. Air tight stoves have a reputation of sometimes causing heavy creosote buildup in the chimney and pipes. This leads to chimney fires, which btw are incredible: very impressive roar, extremely hot, shooting flames, and very intimidating. Keep a chimney fire extinguisher handy if you use an airtight stove. Chimney brushes or soot removers are normally relied upon to solve this problem. A solution that adds US$2-400 is a catalytic converter in front of the flue. This pdf has a good schematic on the last page. Be aware that these converters are susceptible to fouling and even with good care, won't last forever.

 

I had a housemate (1978) who constructed an airtight stove out of 0.25 inch plate steel that got around the creosote problem, and without using a catalytic converter. It produced charcoal - I wish we still had it. He designed it so that a horizontal baffle directed the wood gas away from the flue and past the air intake. This provided enough oxygen to mostly ignite the smoke, creating a marginal afterburner effect, sufficient to make the creosote problem more manageable.

 

The wide stove front was almost completely covered by a pair of doors for loading fuel, the flat steel provided a decent seal. The flue was off the top, back and to the right. The air intake was centered low on the left side and wan controlled by a "kick spin plate", a large round steel cover welded to a bolt threaded into the stove body, centered on the intake vent. You wore thick boots to spin it, thus the name. The baffle was the key, and my mate went through several iterations before he final welded the deal. First he had to put in a gated bypass damper in the baffle, placed under the flue - otherwise there was insufficient initial draft to start the fire and reloading would smoke out the house. The bypass was operated by an L-terminated rod projected out the right side of the stove. Then he put in a U-shaped cut-out in the left edge of the baffle where it lined up with the air-intake. This was needed to ease constricted airflow. In retrospect, he wished he had either added a second, afterburner air intake, or had simply bumped the air intake up higher, off the base plate and closer to the baffle. As it was, air supporting the afterburner effect also tended reduce the pyrolysis effect.

 

The final trick with this stove was arranging the fuel. A big horking air-diverting piece of wood went on the air intake side of the fuel placed under the flue. This seemed essential to get a fast start and an even burn. Perhaps if the air intake had been higher this wouldn't have been essential.

 

A neat feature with the stove is you could operate it with the huge front doors open (baffle bypass open) for short cheery runs. Nice option to have at times.

[Winkelix]

I just had a question about terra preta and cold climates. I know that in the Amazon it has been used. But I couldn't find anything about use in cold climates, such as Canada. I understand that special bacteria in the soil co-exist with the charcoal and slowly release nutrients. But does this work in cold climates? I was thinking maybe the bacteria are sensitive to cold and don't survive to well in a place like Canada.

[freeztar]

I just had a question about terra preta and cold climates. I know that in the Amazon it has been used. But I couldn't find anything about use in cold climates, such as Canada. I understand that special bacteria in the soil co-exist with the charcoal and slowly release nutrients. But does this work in cold climates? I was thinking maybe the bacteria are sensitive to cold and don't survive to well in a place like Canada.

 

Good question!

 

The "wee-beasties" (microbial life in soil) in Terra Preta (TP) is specific to that region and climate.

Here in Georgia, we have a sub-tropical climate and perhaps some of the wee-beasties found in TP can be found in properly prepared soils here. Of course, some will not and other ones (more suited to this climate) will take the place, I think.

 

The abundance of life in Canada (most parts) suggests to me that wee-beasties specific to the regions and climates would be present in the soil. The question then becomes, "What is the relative effectiveness of TP synthesis in colder climates compared to traditional, tropical TP soils?".

 

An important thing to consider is that during summer (the growing season), temperatures rise, which gives life to dormant soil inhabitants. Unfortunately I've not come across an article dealing with this question.

 

Perhaps others will chime in. :)

[Philip Small]

The abundance of life in Canada (most parts) suggests to me that wee-beasties specific to the regions and climates would be present in the soil. The question then becomes, "What is the relative effectiveness of TP synthesis in colder climates compared to traditional, tropical TP soils?".

 

An important thing to consider is that during summer (the growing season), temperatures rise, which gives life to dormant soil inhabitants. Unfortunately I've not come across an article dealing with this question.

 

Perhaps others will chime in. :)

 

Most chars have a liming effect which can bring about dramatic changes in acid soil settings. Bacteria in particular appreciate the rise in pH. Alfalfa/lucerne and wheat can be very responsive to liming.

 

I'll hazard a guess that char-adapted fungi, bacteria, and archaea should be present in all but the most distressed soil. For those cases a biofertilizer approach is a reasonable tactic, ala Jeff Lowenfels' "Teaming With Microbes" (Recommended). You could inoculate a charcoal dominated compost pile with good soil to produce the biofertilizer needed for the distressed soil.

 

There will be differences between species in response to added char, but they should be in residence because soils generally contain charcoal, at least in settings which retain surface soils with a prolonged fire history.

 

From http://soil.scijournals.org/cgi/reprint/66/4/1249.pdf

High levels of charcoal C resulting from repeated historical burning of grasslands, open woodlands, and agricultural crop residues have been reported in soils from Australia and Germany. In this study, five U.S. soils were selected from long-term research plots in widely different agricultural areas. The charcoal C content was estimated...

 

These analyses showed that all five soils contained measurable amounts of charcoal C ... [which] constituted up to 35% of the soil total organic C (TOC).

 

The authors mention a similar high of 30% in Australia. Sad thing is that tillage seems to be responsible for increasing the Char-C% of TOC. The tillage oxidating influence has more effect on the less recalcitrant bits.

 

In Canada, the sweet spot for the desired response to charcoal may well be with smaller, incremental additions simply because the resident microbial community may be set back by single, large additions of new char. The liming potential of charcoal is a factor in this. Fungi can do some amazing things for soil quality. Where fungi species are significant to soil character, a reasonable scenario in Canada, jumping the pH up a click by incorporating 20 tonnes/ha charcoal is not necessarily the best option. Unless we're trying to grow copious amounts of lucerne, in which case jumping the pH up to just below neutral is hard to find fault with.

 

Soil, and simple. Not often used in the same sentence.

[Winkelix]

Thanks for that:)

I have another question about this.

Say I was to add a bunch of charcoal to a garden (assuming is works in a cold climate), how long would it take for any positive effects to take place? I read somewhere that it takes a few years for it to start working. I was just wondering whether any of you know about it, because I might try it on a garden, just to see how it works.

[Philip Small]

...how long would it take for any positive effects to take place?

 

You could band seed with fine char and fertilizer. With a control to compare results against, you coukd determine if short term effects are happening. Banding char with wheat and fertilizer in Australia works the same season. You can also do comparative potted plant studies for a high degree of control. An outdoor native tree and shrub nursery has been using char as a carrier for biofertilizer at planting time, which makes good sense to me. My guess is that fairly immediate effects can be achieved in most circumstances, but it may take a few runs to figure out what actually works.

[DougF]

I just had a question about Terra Preta and the amount of char in a sandy soil? :)

I live in Florida and the soil is very sandy here I was thinking of putting char on my lawn, will this work here and how much should I use? I'm very new to this so if can help I would appreciate it, thanks DougF :)

[Philip Small]

I live in Florida and the soil is very sandy here I was thinking of putting char on my lawn, will this work here and how much should I use?

 

I hope it will work because I am going to try it on my rocky sandy shallow soiled lawn. Planning to crush up some char and apply with my neighbors push-along fertilizer spreader. Going to hit the parts that cook in the sun the most. Hoping to start bumping up the water holding capacity, get a tad of a mulching effect, and boost the near surface microbial community. An aside, I find that mowing higher helps: drives the grass rooting depth deeper, keeps the crown a tad cooler/moister. Long term plan for the current lawned areas is a combo herb garden/thyme lawn - no grass.

[Winkelix]

Thanks for the info. :)

Another question. How pure does the charcoal have to be? Could an impure charcoal with many volatile chemicals in it oxidize faster, or does it really matter?

Impure charcoal is easy to make (dump water on a burning fire), but would it be as effective?

[Philip Small]

impure charcoal is easy to make (dump water on a burning fire), but would it be as effective?

 

I use my impure charcoal. If a run has very high levels of "brown" charcoal, crush+screen is an easy way to sort it out, then can use it to mulch with, or run it in the compost. Save the brownest bits for the next pyrolysis run. But it won't be as effective: brown charcoal doesn't have nearly the porosity, internal structure, or recalcitrance that black char has going for it.

[DougF]

I hope it will work because I am going to try it on my rocky sandy shallow soiled lawn. Planning to crush up some char and apply with my neighbors push-along fertilizer spreader. Going to hit the parts that cook in the sun the most. Hoping to start bumping up the water holding capacity, get a tad of a mulching effect, and boost the near surface microbial community. An aside, I find that mowing higher helps: drives the grass rooting depth deeper, keeps the crown a tad cooler/moister. Long term plan for the current lawned areas is a combo herb garden/thyme lawn - no grass.

This was my idea also although I don't know if we can run it through a spreader?

do to the texture of char (from what I have read ). I also don't want to apply too much.

I also need to make a bigger char pot in order to make enough char for about 1 acre

[Philip Small]

[due] to the texture of char (from what I have read ). I also don't want to apply too much. I also need to make a bigger char pot in order to make enough char for about 1 acre

 

Getting down to a sand-like particle size down is a challenge. I use a screening approach, but crushed charcoal can produce a lot of dust during screening. I like a sloped screen approach because it has a high processing capacity, but the dust can be horrendous compared to the slower bucket and a screen alternative. I predict that it is going to take a few runs for you to figure out how to handily get an acre of granular charcoal!