Hopi farmers have long practiced the principles of sustainability: To live off the land means to live with the land. They grow beans and corn, mostly, coaxing crops from hostile earth with some of the same ceremonies and planting calendars that have served them for centuries. The Hopi try not to plant more than the land can sustain, more than they can grow and eat. They save their best seeds from the previous harvest to plant the following spring. They also store a surplus of these seeds to guard against a catastrophic crop failure...