Amazon's mysterious black earth: Soil found along region riverbanks; Rich in nutrients, stores more carbon
Forests.org, February 25, 2006
Above ground, rainforests like the Amazon basin flourish as biological hot spots with exuberant growth and a riot of plant and animal species.
But the red and yellow soils below are notoriously poor in nutrients and organic matter. Once the lush vegetation is cleared, the heavy rains and tropical sun quickly decompose even that small reservoir.
Except not in thousands of patches dotted along the Amazon River and its tributaries, where dark, friable soil extends metres deep, fertile in nutrients and organic material. In total, an area the size of France may be covered by this Indian black earth, called terra preta do Indio in Portuguese.
"The textbooks say it shouldn't be there. That's justification enough for me to explore why it is there," says Johannes Lehmann, a Cornell University professor specializing in the chemistry and geology of soils.