Difference between revisions of "Terra preta"

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Terra preta, or 'black earth' is a very dark, man-made soil found in the Amazon Basin. It has a very high charcoal content and also contains plant residues, bone and manure. It is very stable and remains in the soil for thousands of years. It is rich of plant nutrients (nitrogen, phosphorus, calcium, zinc, manganese). Its fertility may also be thanks to high levels of [[Micro-organisms in the soil|activities by micro-organisms]].
 
Terra preta, or 'black earth' is a very dark, man-made soil found in the Amazon Basin. It has a very high charcoal content and also contains plant residues, bone and manure. It is very stable and remains in the soil for thousands of years. It is rich of plant nutrients (nitrogen, phosphorus, calcium, zinc, manganese). Its fertility may also be thanks to high levels of [[Micro-organisms in the soil|activities by micro-organisms]].
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It is less prone to nutrient leaching, which is a major problem in most rain forests. Terra preta zones are generally surrounded by terra comum ([ˈtɛhɐ koˈmũ] or [ˈtɛhɐ kuˈmũ]), or "common soil"; these are infertile soils, mainly acrisols,[4] but also ferralsols and arenosols.[5]  Terra preta soils are of pre-Columbian nature and were created by humans between 450 BC and AD 950.[6][7] The soil's depth can reach 2 meters (6.6 ft). Thousands of years after its creation it has been reported to regenerate itself at the rate of 1 centimeter (0.39 in) per year[8] by the local farmers and caboclos in Brazil's Amazonian basin, who seek it for use and for sale as valuable compost.
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Terra preta is more resistant against nutrient leaching, a problem in rain forests.
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Area terra preta twice size of Great Britain.
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Terra preta soils can reach a depth of 6.6 ft or two meters. These soils are said to generate themselves. Some local farmers sell the top layer of their terra preta soil, then let this soil stay under vegetation for 20 years, after which the terra preta layer has grown back with a rate of 1 cm per year.<ref name="TerraWiki">[http://en.wikipedia.org/wiki/Terra_preta Terra preta - Wikipedia]</ref>
  
 
== See also ==
 
== See also ==

Revision as of 07:33, 27 June 2012

Topic in Gardening courses. By John Eagles.
This page is under construction!
Around the Amazon River, there once lived a civilization of what the Spanish thought were primitive people. Due to the contagious diseases that Europeans brought with them, this civilization died out soon after, but they left a treasure for their descendants that's many times more valuable than gold: a fertile soil. The native tribes had learned how to make fertile a soil in a hot climate, which normally is very infertile because it cannot build up humus.
File:Terra Preta.jpg
Right a terra preta soil that was human-made out of an infertile soil as shown left.

The most stable humus is that formed from the slow oxidation of black carbon, after the incorporation of finely powdered charcoal into the topsoil. This process is at the origin of the formation of the fertile Amazonian dark earths or Terra preta do Indio.[1]

Terra preta, or 'black earth' is a very dark, man-made soil found in the Amazon Basin. It has a very high charcoal content and also contains plant residues, bone and manure. It is very stable and remains in the soil for thousands of years. It is rich of plant nutrients (nitrogen, phosphorus, calcium, zinc, manganese). Its fertility may also be thanks to high levels of activities by micro-organisms.

Terra preta is more resistant against nutrient leaching, a problem in rain forests.

Terra preta soils can reach a depth of 6.6 ft or two meters. These soils are said to generate themselves. Some local farmers sell the top layer of their terra preta soil, then let this soil stay under vegetation for 20 years, after which the terra preta layer has grown back with a rate of 1 cm per year.[2]

See also

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