How did the native Amazon tribes create these remarkably fertile and productive soils?

1
Soil Minerals
Terra Preta
Terra Preta de Indio
Carbon
Charcoal
Mystery Soil of the Amazon
dark earth (Portuguese)
How did the native Amazon tribes create these
remarkably fertile and productive soils?
Amazon Basin, Brazil
reduced carbon

• Local farmers prize terra preta
• dug up and sold as potting soil
• yields up to three fold as great as surrounding
  infertile tropical soils
• sustained fertility in intensive use

1867 Ballard S. Dunn, Confederate exile book
Brazil Home for Southerners lauds high fertility
of Amazon dark soil
High Carbon (SOM) content up to 9 compared with
.5 in other soils sometimes over 20 one to two
meters deep
Terra Preta
Conservation Grassland Minnesota
Ferralsol
How have these remarkable soils sustained their
fertility and productivity for five centuries?
1879 explorer Herbert Smith tales of Amazon in
Scribner's Monthly extraordinary fecundity of
cane fields stalks ten feet high big as a
wrist "rich terra preta best in
Amazon fine, dark loam often two feet thick"

• Small Patches
• average 20 hectares (50 acres)
• 350 hectares (865 acres) reported
• near settlements on bluffs
• embedded pottery sherds
• animal fish bones, cultural debris

Age 800-4000 years radio-carbon dating
(charcoal) recent research 6000 years
What can we learn from these remarkable soils to
sustain soil fertility and productivity today?
High nutrient content Calcium
Phosphorus Nitrogen Cation Exchange Capacity (CEC)
1966 Wim Sombroek (Dutch1944-2003) published
his book Amazon Soils first scientific study of
terra preta
Can this method to create tropical soils provide
insights to improve temperate climate soils?

• Made from Ferralsol or Acrisol
• predominant soils in Amazon
• acidic, notoriously infertile
• poor nutrient capacity

1992 Sombroek publishes his first book on terra
preta for carbon sequestration
Can this method to sequester carbon in soil help
us reverse global warming and climate change?
High Microbial activity microbial
reef nitrogenous bacteria (nitrogen fixing)

• Aerial Surveys
• up to 10 of total land area
• able to feed 5-10 million people

2002 Sombroek forms Terra Preta Nova to use
char on farms as a carbon sink
2007 first international biochar conference
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2
Terra Preta
is biochar a nutrient?
Increased Fertility

• higher Phosphorus Calcium
• higher Nitrogen
• increased nutrient availability
• lower acidity
• higher pH buffering
• water retention
• physical structure
• biological habitat (microflora fauna)

In normal soil, biochar breaks down very slowly
(oxidation,weathering digestion) over
centuries, rather than months
Biochar isnt consumed by soil life
Biochar freshly made is sterile, with no
biological activity no microbes
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Adding only biochar to soil retards plant growth
for up to two years
Fertilizers must be added with biochar
biochar
terra preta
acrisol typical Amazon soil infertile
Biochar is a sponge to hold water
nutrients, and a substrate to provide habitat
housing for microbes
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Global Research
Terra Preta
2001
biochar benefits
cation exchange capacity increased
(Glaser) water-holding capacity 18 increase
(Glaser) biomass growth 266 increase (Steiner
2nd year) 324 increase (Kishimoto
Sugiura) plant nitrogen uptake doubled
(Steiner) farm chemical runoff reduced
(Yelverton)
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Research
Terra Preta
3-Year Field Trials
Rice Sorghum
366
267
881
Christoph Steiner1 W. G. Teixeira2 Johannes
Lehmann3 W. Zech1 1 Institute of Soil Science,
Univ. of Bayreuth, Germany 2 Embrapa Amazonia
Ocidental, Manaus, Brazil 3 Dept of Crop and
Soil Sciences, Cornell Univ., USA
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Bark Biochar Fertilizer
Terra Preta
Research
biochar NPK
biochar NPK
NPK
control
control
NPK
Effect of bark biochar and fertilizer on plant
growth and soil properties in south
Sumatra Yamato 2004 unpublished
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