Is it possible that one of the two keywords, either terra or preta, is misspelled?”
Terra preta (“dark earth” in Portuguese) refers to expanses of very dark, fertile anthropogenic soils found in the Amazon Basin. Terra preta owes its name to its very high charcoal content, and was indeed made by adding a mixture of charcoal, bone, and manure to the otherwise relatively infertile Amazonian soil over many years.[1] It is also known as “Amazonian dark earth” or “Indian black earth”. In Portuguese its full name is “Terra preta do índio” or “Terra preta de índio”. Terra mulata is lighter or brownish in color.[2] Terra preta is characterized by the presence of low-temperature charcoal in high concentrations; of high quantities of pottery sherds; of organic matter such as plant residues, animal feces, fish and animal bones and other material; and of nutrients such as nitrogen (N), phosphorus (P), calcium (Ca), zinc (Zn), manganese (Mn).[3] It also shows high levels of microorganic activities and other specific characteristics within its particular ecosystem. It is less prone