1493_ Uncovering the New World Columbus Created - Charles C. Mann [114]
Andean Indians ate potatoes boiled, baked, and mashed as people in Europe and North America do. But they also consumed them in forms still little known outside the highlands. Potatoes were boiled, peeled, chopped, and dried to make papas secas; fermented for months in stagnant water to create sticky, odoriferous toqosh; ground to pulp, soaked in a jug, and filtered to produce almidón de papa (potato starch). The most ubiquitous concoction was chuño, made by spreading potatoes outside to freeze on cold nights. As it expands, the ice inside potato cells ruptures cell walls. The potatoes are thawed by morning sun, then frozen again the next night. Repeated freeze-thaw cycles transform the spuds into soft, juicy blobs. Farmers squeeze out the water to produce chuño: stiff, Styrofoam-like nodules about two-thirds smaller and lighter than the original tubers. Long exposure to the sun turns them gray-black; cooked into a spicy Andean stew, they resemble gnocchi, the potato-flour dumplings favored in central Italy. Chuño can be kept for years without refrigeration, meaning that it can be stored as insurance against bad harvests. It was the food that sustained the conquering Inka armies.
Then as now, farming the Andes was a struggle against geography. Because the terrain is steeply pitched, erosion is a constant threat. Almost half the population cultivates some land with a slope of more than twenty degrees. Every cut of the plow sends dirt clods tumbling downhill. Many of the best fields—those with the thickest soil—sit atop ancient landslides and hence are even more erosion prone than the norm. Problems are exacerbated by the tropical weather patterns: a dry season with too little water, a rainy season with too much. During the dry season, winds scour away the thin soil. Heavy rainfall in the wet season sheets down hills, washing away nutrients, and floods the valleys, drowning crops.
To manage water and control erosion, Andean peoples built more than a million acres of agricultural terraces. Carved like stairsteps into the hills, the Spanish voyager Pedro Sarmiento de Gamboa marveled in 1572, were “terraces of 200 paces more or less, and 20 to 30 wide, faced with masonry, and filled with earth, much of it brought from a distance. We call them andenes” (platforms)—a term that may have given its name to the Andes. (Fifteenth-century Indians used more appropriate methods than those ordered by Mao in the twentieth century, and had much better results.)
On the flatter, wetter land around Lake Titicaca indigenous societies built almost five hundred square miles of raised fields: rectangular hummocks of earth, each several yards wide and scores or even hundreds of yards long. Separating each platform from its neighbor was a trench as much as two feet deep that collected water. During the night the trench water retained heat. Meanwhile, the complex up-and-down topography and temperature variation of the surface created slight air turbulence that mixed the warmer air in the furrows and the colder air around the platforms, raising the temperature around the crops by as much as 4°F, a tremendous boon in a place where summer nights approach freezing.
In many places raised fields were not possible and so Indians constructed smaller wacho or wachu (ridges), parallel crests of turned-up earth