Terra Preta possibly The Next Generation potting media

Terra Preta is also known as Amazon Black Soil. These soils are super rich in nutrients, easily stores nutrients but does not leach out easily, and has high organic matter content. These soils are formed during the start of agricultural times when the first Amazonian civilization started agriculture by slashing rainforests and then turning the biomass into charcoal instead of burning them and then incorporating it into the soil. This retains about 50% of the carbon into the soil and the method produces the least amount of nitrous oxides, particulate matter and other green house gas emissions. The carbon incorporated into the soil becomes very stable and helps in building up the fertility of the soil through the years. Thus with the carbon dioxide being trapped by plants and then itself being trapped into the soil through the years, there is a significant net entrapment of carbon compared to burning of forests during forest fires or agroforestry industries.

Scientists of today are able to duplicate production of terra preta and there is a net entrapment of carbon into the soil, thus potentially reducing the carbon dioxide trapped by plants from the atmosphere. So how does this relate to us citrus hobbyists? Perhaps we need to add real charcoal (not the briquittes from the stores!!!), powder them up and add into composting process, or even into CHC's. The CHC's, real charcoal, and compost would perhaps make the most ideal potting media yet. But if you are not into potting media, at least incorporating some real charcoal into the soil should help build it up through the years. Charcoal briquittes on the other hand I will consider them as "poisonous" to the soil, simply because of the binding agents used to form them. Fortunately, I can dig up some info on how to make real charcoal from my debris of yard waste. I will then use them to try making potting media or improving my soil. I for one really hate leaching out excessive nutrients from container grown plants. Such leacheates from potted plants are big contributors to stream pollution. Charcoal helps by minimizing the leaching of these excessive fertilizers and thus help the environment and conserve our use of fertilizers. There are very active sites in the charcoal itself that helps bind some nutrients when you apply fertilizer, and then are released back when the roots gets in physical contact or intercept those sites. We need to study this more, simply adding charcoal may not be the direct way to do it, but that would be a start.

To learn more about this ancient technology which could help us a lot today, click on the various links below:

http://www.css.cornell.edu/faculty/lehmann/terra_preta/TerraPretahome.htm
http://www.innovations-report.de/html/berichte/geowissenschaften/bericht-55516.html
http://www.newfarm.org/columns/research_paul/2006/0106/charcoal.shtml
http://www.geo.uni-bayreuth.de/bodenkunde/terra_preta/

Joe in an earlier thread Millit gave a link to Use of CHC for potting medium and in this article they were adding #2 charcoal and sponge rock to their mix with good results . They had some good charts with ratios of mix designs.

Joe, this is exceptionally interesting. I have been reading for the last two hours,the first link that you posted, and also related links derived from the Cornell link. Half way through your first link, the Cornell link, I Googled the word "bio-char" and then read through an article about Proffesor Lehmann's, the Cornell professor heading up the bio-char/Amazonian dark earth study. I probably have two more evenings of reading and study on this subject, before I have enugh knowledge on the subject to respond, or ask inteligent questions. I will be back. GREAT POST. - Millet

I am glad that you recognize the importance of this rediscovery. I am really more interested on it to help the environment while at the same time enjoy our hobbies. It is amazing that the very old technology is a very good sustainable way of growing plants, and combined with our current knowledge, I truly find these developments very encouraging.

Now I would be looking on how to improve the backyard soil. Perhaps making charcoal of the pruned biomass instead of dumping all of it to compost bin could help make better soil in the long run. Need to find more knowledge on the most efficient way of making charcoal. I was able to make "bio-char" out of leaves way back in high school. Perhaps could revisit that and do the same. Then add the final product into the soil along with compost. This should produce a soil similar to Amazonian Black soil.

It looks to me as if we've all got some reading to do...homework!

SB

Joe:
I got a question.
Are you saying that the ashes from your burnt wood is good fertilizer?
This is important because I have a wood stove at my back patio that I burn excess wood/papers/ etc... but I just put the ashes to the garbage bin because I thought the ashes are alkaline.

Benny,

Yes and No. If you spread them out and add together with ammonium sulfate or soil sulfur, they can become beneficial. Too much, it becomes toxic to plants. How much is too much, I don't know. But I have been spreading ashes all over the yard but not where my citruses are. Peaches, cherries, apples, pears, they seem to like it. Will not try it on citrus as I am not sure of toxic levels and the alkaline tendency of ashes.

The article points out the long term benefits of incorporating charcoal into the soil. Although it does not have a lot of nutrients, it improves your soil conditions and is more stable conditioner than adding organic matter amendments. Charcoal is better than ashes.

Not ashes, but charcoal is the heart of the matter. The incompletely burned wood.

.....Alan.

Thanks to JoeReal, I haven't gotten much work done today!

This is a fascinating topic on many levels. There are almost too many facets to generate a focused discussion.

There are the global environmental and agricultural issues including 1) the reduction of greenhouse gases from the sequestration of carbon in the bio-char; 2) potential reduction in pollution runoff and methane/nitrous oxide soil emissions due to the unique nutrient binding properties and the persistence of this form of carbon in the soil; 3) potential energy generating capacity through the production of bio-char. There are others.

Then there are the more immediate issues for citrus growers. The way I see it, it is not necessary to precisely replicate the terra preta. One just needs to figure out how to incorporate its advantages into container plant culture. The issues I see here are 1) how you make bio-char and what biomass makes the best bio-char for container culture; 2) how to replicate the high calcium and phosphorus levels in terra preta which one reference attributes to fish and other animal byproducts; 3) the higher pH of the bio-char and determining whether pH adjustments are needed for the growing medium; and 4) the importance, ease, or difficulty, in reestablishing the microbiologic activity unique to terra preta.

Deep into a Google search I have yet to find a site that even hazards a guess on a container growing media based on terra preta. The closest I can come is charcoal additions to media, generally in orchid culture. Also, I'm interested in how one makes bio-char. I would assume that a 55 gal steel drum could be used to make it at home. Any links?

I like the first link the best. But will have to modify it for more efficiency:

http://www.twinoaksforge.com/BLADSMITHING/MAKING%20CHARCOAL.htm

http://www.clt.astate.edu/elind/charcoalvalentine.htm
http://www.fao.org/documents/show_cdr.asp?url_file=/docrep/X5328e/x5328e07.htm
http://www.merseyvalley.org.uk/projects/charcoal.php
http://www.eaglequest.com/~bbq/charcoal/

I have a LOT MORE reading to do before I am up to speed concerning bio-char and Amizon Black Soils. However, I have a question to throw out. The bio-char (charcoal) in the soil is what traps and holds minerals from sources such as rain water, and fertilizer applications. In the case of a fertilizer such as 30-10-10, which has 50 percent active ingredents (NPK) and 50 percent soluble salts. As the bio-char traps these nutrients with in the structure of the bio-char itself, would'nt the soluble salts contine to build up within the container with each repeated fertilizer application, and reach toxic levels? High soluble salts are highly damaging to citrus. - Millet

Additionally, because of the continual trapping of minerals by bio -char, would this eliminate the possibility of flushing out the growing medium three times a year as required for good root health? Would the bio-char just keep trapping additional minerals from the water used to flush the container? - Millet

I can see that this needed to be researched further. My theory could be that the nutrients may build up but would reach some equilibrium which is much higher than ob served with other soils. It may be bound into the bio-char but then can be made accessible by plants through chelation in the presence of microorganisms or by plant root exudates. Interception rather than diffusion of nutrients would also play a big part. Thus it becomes available only when needed or when intercepted and chelated. Like active carbon, there would be too many sites for entrapment of excessive nutrients and these would not easily dissolve into the soil solution except through some biological processes.

Thanks for sharing those links Alan! Excellent follow-up job.