Terra Preta – The Miracle Soil of the Amazon

For a short time, I’ve been invloved in a discussion about something that most of us have never heard of – TERRA PRETA.

A brief background: In 2006 Charles Mann wrote a book 1491: Revelations of the Americas Before Columbus.  I read it back in early 2007, and some of the things in it have stuck with me ever since.  It is a TERRIFIC book.

One of the amazing things I learned was about terra preta – a dark soil in the Amazon that Mann said was a miracle soil.  We all are told over and over again that Amazonian soil is TERRIBLE.  Well, all of it isn’t.  Some of it may be the best soil ever.  Used in agriculture, terra preta lasts indefinitely WITHOUT FERTILIZERS.

Terra preta is a mix of soil, charcoal, and ceramic shards put there by people. It also includes fish bones.  Terra preta averages 40-50 cms deep but in some places it is up to 2 meters deep.  Why, no one knows, because you don’t need half a meter or two meters to grow food.  You normally  only need about 25 cms or less usually.  That is about 10″ of topsoil.

Terra preta was first recognized about 100 years ago, but only in the last 20 years or so has anyone studied it.  And what they have found is amazing.

Terra preta, with its ceramic shards. [Source: NatGeo’s video “Superdirt Made Amazon Cities Possible?”]

First of all, terra preta IS NOT NATURAL.  It is clearly and obviously man-made.  This is known because the ceramic shards are present everywhere terra preta exist – a total area along rivers a little larger than the size of the state of Illinois – but in narrow areas near rivers.

Map Showing Where Terra Preta is Currently known to be Found [Source: Clement et al 2015 “The domestication of Amazonia before European conquest”]

Even when the very dark terra preta soil is 2 meters deep, the ceramic is in it down to the bottom.  The soil is so dark and numus rich that scientists have given it the artificial name of “Amazonian dark earth”, or ADE.  The name ADE is bullshit, because it is terra preta, and has had that name for a very long time.