Maize was domesticated in Mesoamerica, but was rapidly introduced to the north-west corner of South America, presumably by sea. The site of Las Vegas in Ecuador has evidence of maize cultivation by 5000 BC, and by 2500 maize was widely grown in the region.
Further east manioc (cassava) was the staple crop. However, around 800 BC maize also appears at sites in the Amazon basin. Maize had the great advantage over manioc of providing protein as well as carbohydrate, particularly when eaten with beans. Furthermore, it was a crop well suited to the rich alluvial soils of the riverbanks, where the nutrients provided by annual inundation (flooding) increased soil fertility.
Manioc, on the other hand, increases its yield if left in the ground for more than a year but does not tolerate waterlogging, making it less suitable. The cultivation of maize gave a great boost to Amazonian communities: population rapidly increased and villages expanded.
The process is well documented at Parmana on the middle Amazon. Initially the area had a number of small settlements cultivating manioc. Sometime around 800 BC maize began to be grown here. It had become the major crop by AD 100 and the population of the area had increased fourfold.
