Indigenous practitioners around the world have farmed with only rainwater for millennia. But it’s unclear whether conventional agriculture, which relies heavily on irrigation, will learn any of their lessons.
Cream-colored squash and tepary beans ripen on vines and bushes whose roots grasp the heavy clay soil of Arizona’s Tohono O’odham reservation. Prickly pears, oregano and agave grow beneath a mesquite tree in the town of Patagonia, Arizona. And in a downtown Tucson garden, desert ironwood trees shade chuparosa shrubs and wolfberries.
These are just a few of the food plants native to various regions of the Sonoran Desert. It’s a notoriously hot (104°F in August) and dry (it gets three to 20 inches of rain annually) hook of land that juts up from Northwestern Mexico into Arizona, making a pitstop in California before shooting down the Baja peninsula. Indigenous farmers have been coaxing food from this arid turf for thousands of years, “working with the environment, not changing the environment,” says Sterling Johnson, farm manager and mentor at the Ajo Center for Sustainable Agriculture (CSA), where those squash and beans grow.
In 2020, the Sonoran Desert was clobbered by the effects of climate change. Temperatures hit 115°F a record 14 times and less than two inches of rain dropped during the normally more abundant monsoon. Saguaro cacti withered and fruit and vegetable crops faltered. On the Tohono O’odham reservation, the squash vines had a lower germination rate than usual, but they did still produce. Patagonia’s prickly pears and oregano fared just fine, according to University of Arizona ethnobotanist Gary Nabhan, who grew them in his garden. And according to Brad Lancaster, author of Rainwater Harvesting for Drylands and Beyond, who helped build the Tucson garden through a program called Neighborhood Foresters, perennials showed drought stress and went dormant, but when rains returned in the summer of 2021, 98 percent of them rebounded.
Increasingly, the Sonoran and other dry places are showing us what a heat-and-drought-riddled future has in store for more of our food systems. These examples suggest that deep knowledge of dryland farming practices could blunt the impacts, giving some farmers a workable path forward. Whether conventional agriculture is willing to learn anything at all from these systems, however, is the question.