‘Terra Preta de Indios’ (Dark Earth of the Indians) or
Amazonian Dark Earth

Our discovery of Terra Preta, an incredibly fertile soil mixture created and traded by Native
Americans throughout Central and South America, led to intensive study of this amazing
anthropogenic soil. Charles C Mann (2005) is one of the first authors we came across who
discusses this cutting edge indigenous agricultural amendment. As Mann details, this fertile soil
was found in ample deposits on archaeological sites along river bluffs in the Amazon basin.  It is
called “Terra Preta de Indios”, by Amazonian people  and locals claimed the native indigenous
cultures made it. Archaeologists quickly began to suspect its anthropogenic origins when they
realized that this soil was only found at ancient habitation sites, and invariably contained an
unusually high proportion of pot shards. It was, in essence, a perfect ‘potting soil’ in an area with
otherwise thin, clay based soils with poor aeration.
One of the amazing things about this soil is the unique composition of microbial life present within
it. Due to microbes present in the soil, concurrent with its high charcoal content, it literally grows!
This may be hard to believe but it has been studied by scientists and shown to actually result in a
net increase in organic matter as Mann documents. The other extremely exciting property of Terra
Preta, is that it contains a high proportion of carbon from charcoal. This carbon acts like a time
capsule to literally “lock in” the nutrients around it. Only plant roots contain the ‘combination to
unlock’ these capsules. Rain, wind and sun are unable to leach these precious nutrients away. As it
accumulates nutrients, this contributes to the miraculous ‘growth’ of the soil itself. The addition of
charcoal and the pot shards give the soil loft and structure which better aids agriculture, especially
in a rain forest where drainage and moisture retention must be carefully balanced.
Intensive study into the subject led us to the natural conclusion that this ancient soil creation
technique would have incredible value if understood and utilized by milpa farmers here in Belize,
and throughout the developing world.  In tests done in Brazil, it was found to increase yield by
over 800% when added to the soil. This is phenomenal and deserves further study. It is also
interesting to note that so far researchers have been unable to determine how this incredible
microbial balance is achieved. Some speculate that it is created as a starter culture from certain
soils and then added into subsequent batches.
Through studying Terra Preta we have become inspired to create our own modern version, here  
at the STAND Center, utilizing natural industrial wastes.  By transporting truckloads of charcoal
from just one, of many, local limestone burning quarries and mixing this in layers with chicken
manure, leaf debris, sawdust, or other organic waste, a ‘starter culture’ of microbe rich soil, and
river sand, we have been creating our own ‘Terra Preta.’
We are very excited about this and about teaching local people how to do the same to enrich and
protect everything from milpa plots to their village lots. We believe that the discovery and
implementation of Terra Preta on a wide scale throughout Central America has the potential to
revolutionize agriculture! Rather than promoting a style of agriculture radically different than the
slash and burn that is practiced here with such devastation, we are simply encouraging farmers to
‘slash and char’ and add organic fertilizers to the soil. This is a form of on site Terra Preta
creation which does not require much hauling of material to a site. By continually improving the
milpa they are using, they do not have to move continually further and further from the village
which increases their work burden and destroys or badly damages the soil and native ecosystem
along the way. The only difference between slash and burn and slash and char is that the plant
matter is not allowed to dry completely but is burned while the cut brush is still wet and green.
This creates a high proportion of charcoal which then begins absorbing nutrients from the ash, the
rain, and any application of fertilizer.
Our first Terra Preta outreach program is called La Semilla Auténtica’, or The Authentic Seed, and
is a part of a three part program designed to encourage sustainable development in local
communities. The entire program is detailed on our Outreach Programs page which can be
accessed via the navigation bar to your left.
Links to Terra Preta Information:

Terra Preta: Soil Biogeochemistry (Cornell University)

Wikipedia: Terra Preta

Scientific American.com : Trash to Treasure
Terra Preta