The extraordinary fertility of manmade Terra Preta soils in the Brazilian Amazon provided the incentive to study the effects of soil charcoal amendments on soil fertility, nutrient cycling, and soil biology. The existence of Terra Preta suggests that tropical soils, which are notorious for being infertile, can be greatly improved. The agricultural produces charcoal out of fallow vegetation instead of converting it to carbon dioxide through burning. Slash and char improves soil quality by transferring organic carbon into recalcitrant soil organic matter pools. This newly described agricultural practice has important implications for the earth’s carbon budget and sustainability in tropical agriculture.