Agriculture in South America probably began in the tropical Amazon Basin, although no direct evidence of this survives. In the highlands of Peru, crops introduced from the Amazon region were being cultivated by 6500 BC: these included chilis and beans.
By 4500 BC, a large range of Andean and tropical crops were being grown, such as potatoes and other tubers, quinoa (an Andean grain) and squashes, as well as maize (introduced from Mesoamerica).
Around the same time, camelids such as llamas and alpacas were being herded in the highland pastures, kept for meat and wool. They were also used as pack animals, facilitating trade and communications between different regions. Guinea pigs were also kept for meat.
Fishing communities had long been established on the coast and by 2500 BC farming had begun in the coastal river valleys, cultivating a range of crops introduced from the highlands.
Trade between the different zones, and the exploitation by individuals of land within several zones, meant that the resources of each zone were generally available throughout the Andean region. Thus coastal cotton, dried fish and shells would reach the highlands, from which dried llama meat, freeze-dried potatoes and wool could be exported to the coast.
In the coastal valleys, and to a lesser extent in the early highlands, irrigation was used for agriculture, becoming increasingly important through time. Complicated arrangements of canals and irrigation channels would fan out from the rivers to allow farming of otherwise desert land. Construction of these canals was a community venture; the organization for building monumental centres may have originated from this.
