Agricultural history of Peru

Much of the pre-history of Peru was driven by the location of farmable land. The most populated coastal regions of Peru are the two parallel mountain ranges and the series of 20 to 30 rivers descending through its coastal desert. In dry periods only the mountains had enough rainfall for agriculture while the desert coast was empty.

In wet periods many cultures thrived along the rivers. The Inca were a mountain-based culture that expanded when the climate became wetter, often sending conquered peoples down from the mountains into fallow but farmable lowlands. In contrast, the Moche were a lowland culture that died out after a strong El Niño, which caused abnormally high rainfall and floods followed by a long drought.[1]

A study reported that crops of squash, peanuts, and cotton were domesticated in Peru around 10,000, 8,500, and 6,000 years ago, respectively. They were grown by the Ñanchoc people in the Ñanchoc Valley. No earlier instances of the farming of these crops are known.[2]

Aqueduct at Cumbe Mayo

An entrance to Nazca's Puquios

The ancient people of Peru built water-moving and preserving technologies like the aqueducts of Cumbe Mayo (c. 1500 BCE) and the Nazca's underground aqueducts called Puquios (date uncertain), or the terraced gardens of the Huari. Aqueducts were also utilized by the Moche.[6]

Another technique used for farming was terracing. The Chavin,[7] Moche,[6] and Incas built terraces, or andenes, into the sides of hills. The andenes reduced erosion that would normally damage a steep hill. These terraces are still used.[8] Incans irrigated their fields with a system of reservoirs and cisterns to collect water, which was then distributed by canals and ditches.[9]

However, by the mid-19th century, only 3% of Peru's land was still farmable. It lagged behind many other South American countries in agriculture.

In the 19th century the Inca fertilizer guano (saltpetre) became the most important resource in Peru's modern history, for its use as a fertilizer and as gunpowder.[10] The stock of guano built up because the Humboldt current once drew thousands of anchovies and other fish, which in turn, attracted thousands of birds. The population of white-breasted cormorants, gray pelicans and piqueros flourished due to a lack of predators. The guano (droppings) left by the birds retained its nitrate content because of the arid climate.[11] Between 1840 and 1880, Peru sold around 20 million tons of guano, mostly to Great Britain. Peru earned about 2 billion dollars in profit.

Peru lost its guano reserves to Chile (backed by the British Empire) in the War of the Pacific.[12] By the late 19th century, 50% of the Peruvian government's revenue was going to pay off loans that been guaranteed with guano sources taken by Chile - these debts were eventually paid by sending all the remaining guano to France when it was preparing for war. The Germans invented the Haber process shortly after the outbreak of World War I, after which guano became almost worthless.

As Peru's guano reserves began to run out, the government restricted the guano industry to help stabilize the supplies. The collapse of Peru's bird population after the collapse of the fishery limited future supply of the fertilizer.[10]

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  Potato plants
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  Maize ears
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  Rice field
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  Rice plants
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  Flowering coffee tree