Such ancient plant nurseries rested on special soils (or, more strictly, ‘anthrosols’), which are locally called terra preta de índio (‘black earth of the Indians’) and terra mulata (‘brown earth’): dark earths with carrying capacities well in excess of ordinary tropical soils. The dark earths owe their fertility to absorption of organic by-products such as food residues, excrement and charcoal from everyday village life (forming terras pretas) and/or earlier episodes of localized burning and cultivation (terras mulatas).
