Introduction
Terra Preta is a fertile black soil found in parts of the Amazon River basin. It is found near Pre-Colonization villages and was formed by the accumulation of wood char, animal and human waste, dead animal parts, and other forms of organic matter (Factura et. al. 2010). Contrary to the leached and nutrient deficient soils found throughout the Amazon basin, Terra Preta soils are rich in nitrogen, phosphorus and calcium, and are very productive agricultural soils season after season (Deenik et. al 2010). Ample research has been done to theorize how these soils were formed and how current populations can form them.
Terra Preta soils have a great value to farmers in the Amazon basin. Contrary to many farmers who cut and burn a new section of forest every few seasons because the soil is depleted and unable to grow crops, crops in Terra Preta soils have been planted for generations (McKey et. al 2010). Terra Preta soils are known to regenerate themselves at a rate of about 1 cm per year (Barrow 2010). Some farmers have taken advantage of this property in a sustainable manner and have harvested and sold their Terra Preta soil every few years (Heckenberger et. al 2007).
Terra Preta is formed from the accumulation of wood burned in a reduced oxygen environment, known as biochar. It is theorized that human populations can form Terra Preta to create a sustainable alternative to the destructive practice of slash and burn agriculture that destroys the rainforest at an alarming rate. Biochar that was generated by chicken waste and rice crop residue was found to release 40 % more phosphorus then unneeded soil (Jindo et. al. 2012).
Although Terra Preta, like soils containing biochar, have been widely studied in Amazonia, their impact is less known in other regions. One study by Laird et. al. (2010), found that soil amended with biochar tended to be more resistant to so soil compaction and had up to 20% higher cation exchange. A report by the United States...