Skip to Content.
Sympa Menu

permaculture - Re: [permaculture] if there were a benefit to deforestation...

permaculture@lists.ibiblio.org

Subject: permaculture

List archive

Chronological Thread  
  • From: "Lawrence F. London, Jr." <venaurafarm@bellsouth.net>
  • To: permaculture <permaculture@lists.ibiblio.org>
  • Subject: Re: [permaculture] if there were a benefit to deforestation...
  • Date: Thu, 07 Jan 2010 03:52:40 -0500

Tripp Tibbetts wrote:
From what I understand about terra preta, they are still fertile
today, several hundred years later. Biochar is based on the concept, and
is (you probably know this) wood that has had its carbohydrates burned
out, but still retains its carbonaceous lignin structure. The charred
remains act as a sort of liferaft for soil microorganisms, as well as a
concentrated, though recalcitrant, organic carbon source, that persists
in the soil for decades if not centuries. Several contributors to this
list have more expertise in this area than I do.

But apparently the terra preta are visible on satellite images in
areas of the Amazon where indigenous populations lived for thousands of
years. As you know, tropical soils are notoriously thin from constant
leaching, and fertility is generally maintained in the forest biomass
itself. The biochar they produced effectively overcame this limitation,
but the tropical agroforestry systems they used to produce food were
unrecognizable to temperate-zone Europeans, who assumed (incorrectly)
that the small plots of annual crops they could see supported a tiny
tribal populace. They totally overlooked the lion's share of the
cultivated calories.

This discovery in the upper Amazon is on par with the Aztecs, Inca,
Maya, and Egyptians really, lending even more credence to the population
estimates suggested in Toby's article. Which in my opinion is well worth
the read.

Hopefully if we discover another major civilization it won't be with
logging equipment.

Still looking for research that claims that this soil was improved by
addition of ""biochar". I have always been skeptical of making biochar to improve farm and garden soil. Burning creates smoke, a pollutant
and materials burned should be cold composted and then returned to the soil using appropriate tillage methods, sheet composting or deep mulching. To my way of thinking the method I have used on my farm is the model to follow:
1) Prep farmland with:
a) a subsoiler
2) a bottom plow
do this in winter and only when soil has low enough moisture level to
keep compaction from occuring
2) Apply a Yeomans plow using repeated passes scrupulously avoiding driving over plowed areas - obviously I am talking about creating parallel rows of raised beds. The Yeomans plow should be used every year and if possible following each crop prior to planting the next one
3) Apply tillage tool (spring tooth cultivator) to provide initial breaking up of soil, reducing large chunks to smaller ones
4) Use a tractor mounted rototiller (rotavator) to reduce medium and small soil chunks to fine, loose soil; multiple passes will usually be required.
5) Use a large, wide hiller-bedder to create large, wide raised beds with deep, narrow drainage ditches (furrows well below grade) between them - this is consistent with the recommendation of Emelia Hazelip
for shaping and configuring raised, biointensive, heavily mulched garden beds (narrow ditches between the beds for separation and drainage).
6) Before each new planting perform steps 2), 4) and 5) if weeds and or soil compaction or crusting is a problem, otherwise leave the beds as they are, mulch them heavily and move in the direction of elimination of
tractor work leading to permanent notill biointensive raised beds. This will require hand weeding and light hand cultivation with various hoes and tilthing forks. Smith and Hawken actually had Bulldog Tools in England make them small border-type digging forks to use for this purpose to sell to French biointensive notill raised bed gardeners. They called it the Alan Chadwick tilthing fork because he had and used one of these specially designed tools. It is a short D-handled digging fork with a slightly wider head that a border fork. The story was that Chadwick would dance around his beds poking, prying and tilthing the
soil, loosening and breaking crust.

Here are a few more worthwhile references:

Cornell University
Johannes Lehmann
http://www.css.cornell.edu/faculty/lehmann/research/terra%20preta/terrapretamain.html
Terra Preta - Basic Information
"Terra Preta de Indio" (Amazonian Dark Earths; earlier also called "Terra Preta do Indio" or Indian Black Earth) is the local name for certain dark earths in the Brazilian Amazon region. These dark earths occur, however, in several countries in South America and probably beyond. They were most likely created by pre-Columbian Indians from 500 to 2500 years B.P. and abandoned after the invasion of Europeans (Smith, 1980; Woods et al., 2000). However, many questions are still unanswered with respect to their origin, distribution, and properties.

Amazonian dark earths: origin properties management
By Johannes Lehmann
http://books.google.com/books?id=IO9hjqWtHKYC&dq=Terra+Preta&printsec=frontcover&source=bl&ots=2vPbq3m3cn&sig=wyDUeJBrUh6XQxC-zcxCejD5SF0&hl=en&ei=eY9FS86rK8KVtgfwj7HmAQ&sa=X&oi=book_result&ct=result&resnum=11&ved=0CCsQ6AEwCg#v=onepage&q=Terra%20Preta&f=false
Book overview
Amazonian Dark Earths are not only a testament to the vanished civilizations of the Amazon Basin, but may provide the answer to how the large, sophisticated societies were able to sustain intensive agriculture in an environment with mostly infertile soils. Locally known as Terra Preta de Indio or Indian black earth, these anomalous soils are even today fertile and highly productive. Though clearly associated with pre-European settlements questions remain whether the Dark Earths were intentionally produced or merely a by-product of habitation activities. This publication provides a comprehensive review of our current understanding of these fascinating soils: their origin, properties, and management through time. These new and multidisciplinary perspectives by leading experts on Amazonian Dark Earths may pave the way for the next revolution of soil management in the humid tropics.


LL




Archive powered by MHonArc 2.6.24.

Top of Page