They also developed hardy food plants such as the potato, a staple in their diet, and the highland grain crops, quinoa and canagua . Irrigation canals brought water to their fields. Many Indian farmers still employ traditional agricultural methods. Often they use a foot plow to break up the soil, or they may drive oxen hitched to a wooden plow tipped with steel. During the planting of crops the farmer is followed by his wife, who drops the seed.
Children bring up the rear, adding fertilizer and covering the seed.
At harvesttime, in May or June, the family cuts the tough quinoa stalks with a sickle, flails the plant to thresh out the seeds, and tosses the seeds in the air to winnow out the husks. The women grind the seeds and make bread or gruel from the resulting flour. Another popular food is chu o, made from the potato. Spread on the grass in the early winter, the potatoes freeze at night and thaw in the daytime until they become soggy. Then members of the family tramp them to squeeze out moisture and remove part of the peel.