Rain-fed Agriculture Thrived Despite Climate Degradation in the pre-Hispanic Arid Andes

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Rain-fed Agriculture Thrived Despite Climate Degradation in the pre-Hispanic Arid Andes

Unexpected agricultural production allowed pre-Hispanic society to flourish in arid Andes.

Six hundred kilometers south of Lake Titicaca and more than 3700 m above sea level, the Intersalar region, between the two large salt lakes of Uyuni and Coipasa, is dotted with fields of quinoa and numerous communities. Today, this region is the main producer of this pseudo cereal that is exported throughout the world.

Close to these villages, numerous archaeological settlement sites bear witness to an ancient human occupation, dating from between the 13th and 15th centuries. Within an area of 60 x 40 km, the researchers studied 48 sites, at which they identified more than 4500 archaeological granaries that were used for quinoa storage.

But, was the climate at that time similar to the current climate? All climate proxies agree and characterize the period from 1200-1450 CE as dry. Within this drier time interval, the rise of rainfed agriculture in the southern altiplano coincided with a catastrophic volcanic event, the eruption of the Samalas Volcano in Indonesia (1257 CE), that initiated climatic changes lasting several decades, with drops in temperature and precipitation on a global scale.

"The massive success of agricultural production in such an unfavorable environment is very surprising," says Richard Joffre ecologist at the CNRS. "It can only be explained by the development of very specific and detailed environmental knowledge that aimed to save water and avoid frost, and by the mastery of a set of agricultural practices by this pre-Hispanic society.

Many micro-terraces are discernible. We mapped more than 1500 hectares of them. Moreover, very few traces of irrigation systems have been found. Production here was based on an unirrigated agricultural system, something remarkable in these arid conditions."

Read full report and watch a video: EurekAlert

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Agriculture terraces in the Andes, source: Wikimedia Commons

Abstract - Rain-fed Agriculture Thrived Despite Climate Degradation in the pre-Hispanic Arid Andes

Archaeological research suggests significant human occupation in the arid Andean highlands during the 13th to 15th centuries, whereas paleoclimatic studies reveal prolonged drier and colder conditions during that period. Which subsistence strategy supported local societies in this harsh environment?

Our field and aerial surveys of archaeological dwelling sites, granaries, and croplands provide the first evidence of extended pre-Hispanic agriculture supporting dense human populations in the arid Andes of Bolivia. This unique agricultural system associated with quinoa cultivation was unirrigated, consisting of simple yet extensive landscape modifications.

It relied on highly specific environmental knowledge and a set of water-saving practices, including microterracing and biennial fallowing. This intense agricultural activity developed during a period of unfavorable climatic change on a regional and global scale, illustrative of efficient adaptive strategies to cope with this climatic change.

Read full paper: Science Advances

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