I had already reached the conclusion that slash and burn was a post
Columbus phenomena. My reason was
simple. Steel axes and machetes are
necessary in order to clear enough land in a season. The brush and trees have to be felled and
allowed to dry out before burned out.
Stone tools are way too fragile to be productive enough.
Once introduced, along with occasional epidemics, collapse barbarism
took over and populations soon fled into the jungles away from indefensible
population centers. Along the way
populations collapsed from outright starvation and tribal warfare as well as
disease. It all blew away.
Here we learn that a variation of ditch and bank agriculture extended
fully into the amazon as it should have.
As in North America and Mesoamerica, the method is labor intensive. With modern machinery this problem is easily
resolved. Importantly we learn here that
the method applies well into the tropical savannas were drought and flood both
must be managed.
The ultimate sustainable population in the amazon will be a billion
plus as this method and its sister Terra Preta soils are both reintroduced and
mastered with modern equipment. It is noteworthy that the banks held nutrients
even in the face of the unrelenting tropical conditions without the addition of
biochar. I suspect that the ditches
provided shallow surface drainage that prevent deeper nutrient escapement. It was all a hydraulic trick.
800-year-old farming
techniques can teach us how to protect the Amazon
Tuesday, April 10, 2012
By Spero News
In the face of mass deforestation of the
Amazon, we could learn from its earliest inhabitants who managed their farmland
sustainably. Research from an international team of archaeologists and
paleoecologists, published today (9 April 2012) in the journal Proceedings of
the National Academy of Sciences, shows for the first time that indigenous
people, living in the savannas around the Amazonian forest, farmed without
using fire.
Led by the University of Exeter, the research
could provide insights into the sustainable use and conservation of these
globally-important ecosystems, which are being rapidly destroyed. Pressure on
the Amazonian savannas today is intense, with the land being rapidly
transformed for industrial agriculture and cattle ranching.
By analysing records of pollen, charcoal and
other plant remains like phytoliths spanning more than 2,000 years, the team
has created the first detailed picture of land use in the Amazonian savannas in
French Guiana. This gives a unique perspective on the land before and after the
first Europeans arrived in 1492.
The research shows that the early inhabitants
of these Amazonian savannas practiced 'raised-field' farming, which involved
constructing small agricultural mounds with wooden tools. These raised fields
provided better drainage, soil aeration and moisture retention: ideal for an
environment that experiences both drought and flooding. The fields also
benefited from increased fertility from the muck continually scraped from
the flooded basin and deposited on the mounds. The raised-field farmers limited
fires, and this helped them conserve soil nutrients and organic matter and
preserve soil structure.
It has long been assumed that indigenous
people used fire as a way of clearing the savannas and managing their land.
However, this new research shows that this was not the case here. Instead, it
reveals a sharp increase in fires with the arrival of the first Europeans, an
event known as the 'Columbian Encounter'. The study shows that this labour-intensive
approach to farming in the Amazonian savannas was lost when as much as 95 per
cent of the indigenous population was wiped out as a result of Old World
diseases, brought by European settlers.
The results of this study are in sharp
contrast with what is known about the Columbian Encounter's impact on tropical
forest, where the collapse of indigenous populations after 1492 led to
decreased forest clearance for agriculture, which in turn, caused a decline in
burning. This study shows that high fire incidence in these Amazonian savannas
is a post-1492, rather than pre-1492, phenomenon.
Dr Jos--riarte of the University of Exeter,
lead author on the paper, said: "This ancient, time-tested, fire-free land
use could pave the way for the modern implementation of raised-field
agriculture in rural areas of Amazonia. Intensive raised-field agriculture can
become an alternative to burning down tropical forest for slash and burn
agriculture by reclaiming otherwise abandoned and new savannah ecosystems
created by deforestation. It has the capability of helping curb carbon
emissions and at the same time provide food security for the more vulnerable
and poorest rural populations."
Dr Mitchell Power of the University of Utah
said: "Our results force reconsideration of the long-held view that fires
were a pervasive feature of Amazonian savannas."
Professor Doyle McKey of the University of
Montpellier said: "Amazonian savannas are among the most important
ecosystems on Earth, supporting a rich variety of plants and animals. They are
also essential to managing climate. Whereas savannas today are often associated
with frequent fire and high carbon emissions, our results show that this was
not always so. With global warming, it is more important than ever before that we
find a sustainable way to manage savannas. The clues to how to achieve this
could be in the 2,000 years of history that we have unlocked."
Dr Francis Mayle of the University of
Edinburgh said: "We've got an unprecedented record of these Amazonian savannas
that completely overturns previous assumptions about the way in which ancient
cultures utilized these globally-important ecosystems."
Dr Stephen Rostain of CNRS said "These
raised-field systems can be as productive as the man-made black soils of the
Amazon, but with the added benefit of low carbon emissions."
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