Since manioc (cassava) has only soft parts and sets no seed, no evidence remains of its earliest cultivation, though that this may have began as early as 5000 or even 7000 BC. Manioc is a rootcrop that takes at least 6 months to mature, though it will increase in size until 18 months; and it does not tolerate waterlogging.
This means that, although it can profitably be grown on the annually flooded alluvium (soils deposited by rivers) of the Amazonian rivers, it is better suited to the poorer forest soils that make up the vast majority of the Amazonian lands.
Sweet manioc, which has a poisonous skin, is used as a vegetable in stews or fermented to make beer. This is drunk today in copious quantities at fiestas, of which drunken brawls form a much appreciated part.
The bitter manioc contains poison throughout; removing this is a long and complicated process. Nevertheless, bitter manioc is the more important crop, since it contains more starch that the sweet variety, of a type that can be made into bread or flour which keeps indefinitely. This makes it suitable not only for storage but also for exchange.
It is used widely in trade throughout Amazonia today and was probably so used in the past also.
