Terra preta For newbies

[Michaelangelica]

New to the idea of Terra preta? (TP)

 

Want to ask a dumb question?

Here is the place to do it

We have been discussing it almost on a daily bases on Hypography for more then a year now and we might have some wisdom to share (Erich ?)

(Although personally the more I find out the more I realise I don't know.)

 

"Old" list members is this OK with you? Want to share your knowledge and experience?

[RBlack]

To all,

 

I am always willing to share what I have done (see todays post on making biochar). As a teacher I am always answering questions anyway. Same as a parent.

 

RB

[freeztar]

Ok, I'll start then...

 

What kind of absorbtion rates can be expected and what chemicals are affected? How does TP compare to other forms of sinks?

 

Also, a really basic question...

How does char differ from slash and burn? In other words, what makes slightly burnt material better than totally burnt material?

[RBlack]

To Freeztar,

 

Charcoal adsorbs not absorbs. The difference is that ions are captured by electrostatic forces to the surface of the charcoal. Charcoal adsorbs almost everything (within reason) that it comes across. That is why charcoal is used in purifying systems for both water and air and is even given to poison victims to adsorb whatever they ingested. As far as rates and amounts I don't have that information. Also there is some difference between activated charcoal and what we make at home (see Wikipedia for definition of activate charcoal). What we make at home has about 70% carbon and the rest is impurities and this gets to your next question.

 

The higher the charring temperature the less impurities you get in charcoal. But it is these impurities across what is called the combustion continuum that makes charcoal in soil work. All of this is controlled by what material you char and what temperature you char it at. Everything I have read on carbon/charcoal/biochar states that there is some uncertainties in the results of all the studies. This is because of all the above variables and some studies look for "apples" in charcoal and some look for "oranges". The basic idea in making Terra Preta is to do what the Amazonian Indians did (or as close as we can come), and char up lots of different material and mix it with lots of different organic matter, put it in the soil and see what happens.

 

RB

[freeztar]

Thanks for the clarification.

I'm still a little puzzled about the impurities part, but I'm sure I'll understand if I hang around long enough. :)

 

So, for adsorbtion to be most effective, it would seem like you would want the most surface area possible. Is crushing a normal practice with char?

[RBlack]

Freeztar,

 

One of the main people on this site (erich) has a great post on the surface area of charcoal.

The reason TP has elicited such interest on the horticultural side of it's benefits is this one static:

 

1 gram of charcoal cooked to 650C has a surface area of 400m2, now for conversion fun;

 

One ton of charcoal has a surface area of 400,000 Acres!! which is equal to 625 square miles!!

 

Now at a field application rate of 2 lbs/sq ft (which equals 1000 sqft/ton) or 43 tons/acre, this yields 26,000 Sq miles of surface area per Acre.

 

 

I have also read that the size of charcoal dosen't make that much difference (within reason of course), and that roots grow around charcoal pieces and even into them!

 

Here is a list of references that I give out when I talk about Terra Preta. These are the best sites/articles that I have found.

 

Terra Preta

Articles, Links, and References

Randy Black 605-574-2884, [email protected]

 

Introductory Information

Cornell University – Johannes Lehmann is one of the major researchers in Terra Preta technology, history, and applications.

Terra Preta home

 

Delta Farm Press – History of Terra Preta and interview with Johannes Lehmann

Terra preta: unearthing an agricultural goldmine

 

British Broadcasting Company – A program summery of a documentary on Terra Preta

BBC - Science & Nature - Horizon - The Secret of El Dorado

 

Nature Magazine Article – “Black is the New Green”, August 2006. Most high profile article on Terra Preta to date. (Long address but you save a $30 subscription fee!) You have to copy and paste this link to get access.

http://www.css.cornell.edu/faculty/lehmann/biochar/WCSS2006/Marris%202006%20Black%20is%20the%20new%20green%20Nature%20442,%20624-626.pdf

 

 

Research Articles/Websites

18th World Conference of Soil Science – 40 or more abstracts of paper presentations on Terra Preta and Biochar. The most up to date information and research available. Just type in search words and go.

The 18th World Congress of Soil Science (July 9-15, 2006)

 

Charcoal as a Potential Tool for Land and Water Remediation – Excellent article for the relationships between charcoal and microbial life.

Charcoal as a Potential Tool for Land and Water Remediation

 

Amazonian Dark Earths – A good referenced article by Natasha Celine summing up the history, properties, and uses of Terra Preta including carbon sequestration

Amazonian Dark Earths by Natasha Celine — conservation, forest, slash and burn | Gather

 

Ameliorating Physical and Chemical Properties of Highly Weathered Soils in the Tropics with Charcoal – a Review by Bruno Glasser. This is a great article on the documented science associated with Terra Preta soils. This is not available online but I can send you a copy [email protected]

 

Nutrient Availability and Leaching in an Archaeological Anthrosol and Ferralsol of the Central Amazon Basin: Fertilizer, Manure and Charcoal Amendments by Johannes Lehmann. The best referenced article on the application of charcoal in creating Terra Preta soils. You have to copy and paste this address to get access. http://www.css.cornell.edu/faculty/lehmann/publ/PlantSoil%20249,%20343-357,%202003%20Lehmann.pdf

 

 

Biochar Information

Cornell University website for introductory information on biochar

Biochar home

 

Slash and Char: A Feasible Alternative for Soil Fertility Management in the Central Amazon by Johannes Lehmann. Good science on the application of biochar and its affects on soil. You have to copy and paste this link to get access.

http://www.css.cornell.edu/faculty/lehmann/publ/Lehmann%20et%20al.,%202002,%20WCSS%20Bangkok,%20paper%20no.0449.pdf

 

Online Information Sites

Hypography Science Forums – Online website where you can ask questions (Quality information sign up is free), about Terra Preta. These are people who are growing, using, and sharing their knowledge of Terra Preta, websites, and related material.

http://hypography.com/forums/earth-science/3451-terra-preta.html

 

Terra Preta Discussions Forum – Another good sites with quality information on all aspects of Terra Preta

[email protected]

 

Anthropology

Historical contingencies in the coevolution of environment and livelihood: contributions to the debate on Amazonian Black Earth. Laura A German – Good article for Terra Preta background and current usage in the Amazon

http://www.soils.wisc.edu/soils/courses/875/14Exemplary(A).pdf

 

Ceramic Artifacts in Terra Preta Soils – Long technical article but the only one that addresses ceramics in Terra Preta.

http://www.scielo.br/pdf/aa/v34n2/v34n2a03.pdf

 

Soil Science

Humus: Still a Mystery – Great article on humus and its importance to the soil

NOFA Interstate Council: The Natural Farmer. Humus. Paul Sachs

 

University of Massachusetts – Best most concise articles on soil structure, texture, and soil science basics.

UMass Extension Vegetable Program - Soil & Nutrient Management

 

Cation Exchange Capacity – Good short article on this subject

Cation Exchange Capacity

 

 

This of course is not even 10% of what is out there. If you google on enough topics you can find slide shows, intense journal articles, and more stuff than you can look at.

 

Good Luck,

RB

 

PS Some of these address didn't transfer well but just google and you can find them quick.

[freeztar]

:)

 

That'll keep me busy for awhile....Thanks!

[Michaelangelica]

Thanks for the clarification.

I'm still a little puzzled about the impurities part, but I'm sure I'll understand if I hang around long enough. :shrug:

 

So, for adsorbtion to be most effective, it would seem like you would want the most surface area possible. Is crushing a normal practice with char?

I agree with what has been said

To add a little

Charcoal is organic matter burnt without oxygen.

Ash is organic matter burnt with oxygen.

Both have very different effects on the soil

Look at

View topic - Any uses for wood ash? - Permaculture discussion forum

or

Wood ash is a useful garden fertiliser, containing 5-10% K2O (potash), and should be applied in early spring at 125-270g/m2 for improved growth of fruit, flowers and potatoes. It's particularly useful on acid, sandy soils, but should not be applied to chalky soils. Store the ash in a dry place

or

The largest component of wood ash (about 25 percent) is calcium carbonate, a common liming material that increases soil alkalinity. Wood ash has a very fine particle size, so it reacts rapidly and completely in the soil. Although small amounts of nutrients are applied with wood ash, the main effect is that of a liming agent.before use.

Wood Ash in the Garden

or

Because it's alkaline you can use it to sweeten up compost heaps, ...

 

Because of its alkalinity, make sure that you keep any wood ash away from acid-loving plants. Keep it away from ground to be used for growing potatoes and don't let it near any seed potatoe

Totally Practical: Wood Ash Factsheet - Gardening Australia - ABC

 

pH is one of the most important "soil variable" to growing good plants.

[maikeru]

:shrug:

 

That'll keep me busy for awhile....Thanks!

 

If you can, put the Nature article on terra preta right at the top of the list. It was and is one of the most informative sources on terra preta. I love that magazine. It and Science are my bibles.

 

Also, I think the impurities do play a large role in terra preta. While the key to terra preta may be to include charcoal of some sort, to do a multitude of things (like adsorb nutrients, organic molecules, etc. and provide living spaces and encouragement to soil microbes), I have a feeling that the impurities help provide for robust and healthy growth of the microbes and plants. They can't live on carbon alone.

 

Even in my homemade stuff, I add eggshells, coffee grounds, tea leaves, and pulped seaweed to try to include as many minerals and elements as I can into the soil. The Amazonian Indians apparently were adding things like kitchen refuse, fish bones, ceramics, and maybe manure.

[mom person]

When you said "Now at a field application rate of 2 lbs/sq ft", I was wondering if that is a reccommended application rate. It is approximately what I have been using on my first experimental plots.

[Michaelangelica]

When you said "Now at a field application rate of 2 lbs/sq ft", I was wondering if that is a reccommended application rate. It is approximately what I have been using on my first experimental plots.

O Dear

For a newbie you ask such a hard question.!!!

 

In a Japanese experiment they have been adding 100g of bamboo charcoal to tea trees for 4 years. (100g per sq meter, per tree, per year.) They already have measurable results. The treated trees are much bigger. They plan to carry on the experiment for another 6 years

There is still much research that needs to be done but in pots 10-20% seems to be the level of char that gets optimum results. Over 20% results are not as good

So do you whack 20% char on your field from day one or add a bit every year? Who knows?

I am always of the opinion that more is better so personally I would add as much char as I could afford.

I Think/believe that char gets better with age so a little every year might also have some benefits. There is no science to support my faith however.

[mom person]

OK. I just did the math on thae Japanese trial and that is about 3.5 ounces per ten fquare feet per year. I am sure that if that much is making a difference, that my approximate two pounds per square foot will do nicely. I am sure that I am nowhere near the 20% cutoff point, but I no longer feel as if I am doing too little. Thanks for the ego boost and the rapid reply.

[RBlack]

To mom person,

 

They lower number you got may be correct. From the latest information I am getting you don't need anywhere near the 20% figure. I will try and get more information to you as I get it. Also remeber that Terra Preta also needs soil organic matter, and I believe biochar which is char from non-woody sources. Also there seems to be reasons to believe that you may need char from across the combustion continuum from partial char to charcoal and possibly higher than normal sources of calcium and phospherous to replicate the fish residues that the Amazonian Indians put into their soil. All of this has to do with establishing the microbial community and at this point we get to the fact that we are dealing with a complicated system and there are no easy or pat answers. The mess I put in my soil this year was charred manure, charcoal from pine and aspen, charred pine needles, composted kitchen wastes, bonemeal and regular NPK for vegetables. What I was trying to replicate was the haphazard mix the Amazonian Indians may have had and I do haphazard well!

 

RBlack

[mom person]

If haphazard is the key, then both of us will succeed. I think that the original terra preters just threw everything into the pit, wood, twigs, manure, and the bones of whatever. Sounds a bit like what I throw into the compost pit. I was wondering what it would be like to make such a pit, but I think that would not go over too well on my lot in Boston. Neighbors, ordinances, etc.

I would love to find a way to make small batches of charred "pit material" in the city. Any ideas?

[Michaelangelica]

I only just learnt this about Hypography

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[erics2112]

Unlike many other posters, I live in a neighborhood that doesn't allow open burning (i.e. in an old drum or in a pit). Is there a decent brand of charcoal that can be purchased? Is it possible to use a covered BBQ grill to make small quantities of bio-char?

[Philip Small]

Is there a decent brand of charcoal that can be purchased? Is it possible to use a covered BBQ grill to make small quantities of bio-char?

 

Erich tells us, for those of us in Memphis:

 

"you can buy charcoal for $125/ton in Bell Mo. at Dustin Strumph Charcoal yard. They have 22ton loads of dust to 1/2 inch , 4-7% moisture."

 

Lowes carries bags of Cowboy brand charcoal, a good place to start.

 

For making charcoal, I started with (and still break out) a small retort (can be made from a cracker tin, or tea tin for micro batches) on the BBQ grill, so yes, it is possible, and I recommend it to experience the process at a bench test level.

 

The drier the feedstock, then the less attention-getting thick smoke there is. The hotter/drier the day, the faster it goes.

r

Doug Hauge of Fillmore, California, says:

 

"I make my [drawing stick] charcoal in a retort. My retort consists of a steel teapot that was once glass coated. Its volume is about one-half gallon. I load the retort, place it on a back-pack type camping stove (just a burner screwed to a propane tank) and cook the wood in the teapot with the lid on. As a result of destructive distillation, flammable gases are emitted from the spout. As the cooking is in progress I light a match to the gases coming out of the spout and know that the charcoal is done when the flame is gone."

 

Some folks here were working on a solar powered charcoal maker, but I can't remember if that was ever successful