books.google.co.id - Amazonian soils are almost universally thought of as extremely forbidding. However, it is now clear that complex societies with large, sedentary populations were present for over a millennium before European contact. Associated with these are tracts of anomalously fertile, dark soils termed terra preta...http://books.google.co.id/books/about/Amazonian_Dark_Earths.html?id=46bEXHqB_vYC&utm_source=gb-gplus-shareAmazonian Dark Earths
