[permaculture] Fertile Soil = Terra Preta + Plaggen Soils

Lawrence F. London, Jr. lfl at intrex.net
Sun Sep 22 20:53:52 EDT 2002

Subject: Fertile Soil = Terra Preta + Plaggen Soils
Date: Sun, 22 Sep 2002 16:26:29 -0500
From: Steve Diver <steved at NCATARK.UARK.EDU>

Fascinating resources on Terra Preta and Plaggen Soils.....

Steve Diver

By Charles C. Mann
The Atlantic Monthly | March 2002


"In the late 1990s Woods and others began careful measurements
in the lower Amazon. They indeed found lots of inhospitable
terrain. But they also discovered swaths of terra preta -- rich,
fertile "black earth" that anthropologists increasingly believe
was created by human beings."

"Terra preta, Woods guesses, covers at least 10 percent of
Amazonia, an area the size of France. It has amazing properties,
he says. Tropical rain doesn't leach nutrients from terra preta
fields; instead the soil, so to speak, fights back. Not far from
Painted Rock Cave is a 300-acre area with a two-foot layer
of terra preta quarried by locals for potting soil. The bottom
third of the layer is never removed, workers there explain,
because over time it will re-create the original soil layer in
its initial thickness. The reason, scientists suspect, is that
terra preta is generated by a special suite of microorganisms
that resists depletion. "Apparently," Woods and the Wisconsin
geographer Joseph M. McCann argued in a presentation last
summer, "at some threshold level ... dark earth attains the
capacity to perpetuate -- even regenerate itself -- thus
behaving more like a living 'super'-organism than an inert
material." "

"In a process reminiscent of dropping microorganism-rich
starter into plain dough to create sourdough bread, Amazonian
peoples, he believes, inoculated bad soil with a transforming
bacterial charge."

Terra Preta Web Site

'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."

Terra Preta Symposium
June 13 - 14, Benicassim, Spain

Especially see:

History and origin of Terra Preta soils and future perspectives

The Terra Preta phenomenon - a model for sustainable
agriculture in the humid tropics

Terra Preta Publications

Especially see:

Conry M J, 1974. Plaggen soils, a review of man-made raised soils.
Soils and Fertilizers, 37: 319-326.

On plaggen soils, see:

Mineral Soils conditioned by Man || Anthrosols (AT)

"The Reference Soil Group of the Anthrosols holds soils that
were formed or profoundly modified through human activities
such as addition of organic materials or household wastes,
irrigation or cultivation. The group includes soils otherwise
known as `Plaggen soils', `Paddy soils', `Oasis soils' and
`Terra Preta do Indio'."

Lecture Notes on the Major Soils of the World
FAO 2001

Concepts of Soil Genesis / Classification
University of Florida

"For example, in the Middle Ages it was well know that manure
applied to soils improved crop growth. For instance, the 'Plaggen
cultivation' was practiced for a long time in Europe, which left
'Plaggen soils': The top of grassland was peeled off and used as
litter in the stables. This material mixed with manure was applied
to arable land to improve crop production."

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