After the arrival of hunter-gatherers in the southwestern region of North America, several alternative types of agriculture emerged, all involving different solutions to the Southwest’s fundamental problem: how to obtain enough water to grow crops in an environment in which rainfall is so low and unpredictable that little or no farming is practiced there today. People experimented with alternative strategies for almost a thousand years in different locations, and many experiments succeeded for centuries, but eventually all except one succumbed to environmental problems caused by human impact or climate change.
