TUCSON – Indigenous peoples have known for millennia to plant in the shade of the mesquite and paloverde trees that mark the Sonoran Desert here, protecting their crops from the intense sun and reducing the amount of water needed.
The modern version of this can be seen in the Santa Catalina Mountains north of Tucson, where a raised solar panel awning helps protect rows of squash, tomatoes, and onions. Even on a November afternoon, as the temperature climbs into the 80s, the air under the panels remains comfortably cool.
Such adaptation is at the heart of ongoing research at Biosphere 2, a unique center affiliated with the University of Arizona that is part of a movement to reimagine and remake agriculture in a warming world. In the southwest, projects are turning to plants and farming practices that Native Americans have long used as potential solutions to growing concerns about future food supplies. At the same time, they seek to build energy resilience.
“We use indigenous knowledge,” said Greg Barron-Gafford, a professor who studies the intersection of plant biology and environmental and human factors. But instead of relying on the shade of trees, “we are under an energy producer who is not competing for water.”
Vegetables such as squash, tomatoes and onions are monitored in the Biosphere 2 agrivoltaic project. Planting crops under solar panels is a 21st-century version of farming techniques used by indigenous people in the Southwest, notes Greg Barron-Gafford, who leads research at the facility north of Tucson. Dozens of solar panels soar skyward as part of the project.
On both sides of the Arizona-Mexico border, scientists are planting experimental gardens and pushing the potential of an “agrivoltaic” approach. Thirsty crops such as fruits, nuts, and leafy greens – which require elaborate irrigation systems that have drawn large amounts of water from underground aquifers and the Colorado and other rivers – are nowhere to be found.
“For 5,000 years, farmers have tried different strategies to cope with heat, drought and water scarcity,” said Gary Nabhan, an ethnobotanist and land activist who focuses on plants and crops. from the Southwest. “We have to start translating this.”
Some of the methods of Biosphere 2 – a facility marked by the largest closed ecological system in the world – are applied in fishing villages on the parched coast of Sonora in Mexico. A multi-year effort there will ensure sources of water, energy and food for some 1,500 members of the Comcaac (or Seri) community.
Other researchers are creating a model of sustainability for urban settings.
The University of Arizona Desert Lab on Tumamoc Hill will inaugurate Tumamoc Gardens of Resilience next spring, an initiative that will be located at the foot of a saguaro-strewn hill in an 860-acre ecological reserve in heart of Tucson. It will show how people can feed themselves in a much hotter, drier future.
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The heart of the project design will be the passive harvesting of rainwater to support a variety of edible plants adapted to drylands. Some of these will be planted under solar panels, while others will benefit from age-old strategies such as rock berms and rock piles to increase humidity, according to Benjamin Wilder, director of the laboratory.
Southern Arizona is an epicenter of the movement, not only because of the intense environmental pressures the region faces, but also because of the Tohono O’odham Nation’s presence southwest of Tucson.
Tohono O’odham farmer Sterling Johnson has a long history of raising awareness of the nation’s traditional farming practices and values. The San Xavier Co-operative Farm is run by members of the Tohono O’odham Nation of the Tucson area. The crops grow on the San Xavier Cooperative Farm.
The Tohono O’odhams have cultivated in the Sonoran Desert for several thousand years. Like many indigenous groups, they are now on the front lines of climate change, with food security a primary concern. Their vast reserve, almost the size of Connecticut, has only a few grocery stores. It is a food desert in a desert where conditions are becoming more and more extreme.
Since the early 1970s, a group of Nation members have run the San Xavier Cooperative Farm and cultivate “traditional desert cultivars” in accordance with their ancestral values, in particular respect for the land, water and land. plants.
Sterling Johnson, a member of the Tohono O’odham Nation, has worked for the past decade to share this expertise on a large scale. His partner, Nina Sajovec, heads the Ajo Center for Sustainable Agriculture, a Native American-led food justice organization that several years ago founded its own seed bank and has already distributed more than 10,000 seeds to farmers.
“We’re all about using what’s out there,” Sajovec said. Among the heirloom varieties in the center: 60-day corn, a fast-ripening vegetable adapted to the desert, and tepary bean, a protein-rich legume particularly suited to the climate because of its leaves that can fold up to withstand direct light. of the sun during the peak of summer. .
Johnson captures rainfall during the monsoon season in Arizona to support his field’s crops in the desert lowlands. “It’s using rainwater,” he explained, “using the contour lines, using your environment and nature to grow food”.
This once common agricultural practice in arid lands has been all but erased by that country’s Indian boarding system, which has “torn” children from their families and interrupted the transfer of knowledge, he noted. The growing interest in native ways is generally welcome, but again it can sound like “Anglo society takes when it needs something”.
“We would really love to see these cultures and techniques… still being used to serve the Aboriginal community,” Johnson added.
Scientist Greg Barron-Gafford checks a meter under the solar canopy at Biosphere 2. Specialized equipment monitors air and soil conditions. Trainees working on the agrivoltaic project record key measurements of uncovered plants.
Perhaps even more frightening than the rising temperatures due to climate change are the water shortages that many parts of the world will face. In Tucson, the Santa Cruz River is now dry due to too much diversion and increasing demand, according to Brad Lancaster, a rainwater harvesting expert.
“The majority of the water that irrigates the landscapes and Tucson and Arizona is not local water,” but is drawn from the Colorado River, Lancaster said. Unless severe drought conditions reverse and river levels improve, mandatory federal cuts mean farmers will lose a significant amount of this essential resource starting next year.
“The goal is how to use rainwater and stormwater, passively captured, to be the primary irrigator,” said Lancaster, who lives in a local neighborhood that has been transformed by passive water harvesting. into an “urban forest”, with edible wild foods. plants such as chili pepper and desert hackberry line the sidewalks.
It provides for a system similar to Tumamoc’s resilience gardens, using ponds and earthen structures to distribute water throughout the landscape and reduce channeled flows. Nabhan, who is also involved in the design of the site, sees it as repeatable and, most importantly, scalable.
“We hope [planting] these gardens will be the same as planting an apple orchard, ”said Nabhan, strolling through his own creation at his home in Patagonia, a small town about 30 kilometers north of the Mexican border. The fenced space contains 40 species of agave, three species of sotol, prickly pear and other varieties of cacti and succulents.
“The key concept,” he said, “is that we are trying to adapt cultures to the environment rather than remaking the environment.”
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