Terra Preta de Indio
The application of biochar into soils is not a new concept. Native pre-Columbian civilisations in the Amazon Basin added biochar to their soils and increased their fertility. Whether they did it on purpose or by accident is uncertain. Because of their black colour and origins, these soils are known in Portuguese as Terra Preta de Indio (Indian black earth).
Typically, Terra Preta (TP) soils are found in patches of approximately 20 ha containing higher soil organic matter, greater concentrations of nutrients such as N, P, K, and Ca, and up to 70 times more biochar than surrounding infertile soils. Biochar alone is not responsible for the formation of these highly fertile soils. Research shows that nutrients in TP soils were incorporated in the form of human and animal excrements, aquatic and terrestrial biomass, and food residues such as mammal bones, fish bones, and turtle backs.