Is that the stink joke?
I'm studying terra preta at the moment and its found to be the most consistently fertile soil on earth! A combination of the slash-burn technique, human waste and for some reason (as yet undiscovered) pottery urns in which they buried their dead, raised the soil organic matter. This SOM is more stable than other soils and can be repeatedly cultivated without losing fertility. Thats why locals in brazil sell it, its super soil basically.
Large civilizations were found to have existed in areas where terra preta is found, supported agriculturally by the soil.
Check this link out
http://www.bbc.co.uk/science/horizon...eldorado.shtml
