Thinking Like a Desert

Gary Paul Nabhan on how Tucson can be a living, learning lab for growing food in a hotter, drier land.

June 23, 2013

HomesteadIssue 1: Summer 2013

Got climate change? Still want to grow food?

Who isn’t faced by the challenges of climate uncertainty these days? Climatologists associated with the Institute of the Environment at the University of Arizona see growing evidence that extreme summer heat, extended drought and water scarcity are becoming “the new normal” across much of North America. Weather shifts have become a new threat to U.S. food security, as farmers and ranchers across the country face unprecedented challenges in producing food under changing conditions.

A small market stand shows the bounty that can be grown in the desert with rainwater alone. (Photo reproduced with permission from <i>Rainwater Harvesting Drylands and Beyond, Volume 1, 2nd Edition by Brad Lancaster)

A small market stand shows the bounty that can be grown in the desert with rainwater alone. (Photo reproduced with permission from Rainwater Harvesting Drylands and Beyond, Volume 1, 2nd Edition by Brad Lancaster)

At the same time, there is growing recognition that Tucson and its surrounding farmscapes have much to teach food producers in the rest of the country on how to adapt to climate uncertainty. With the oldest continuous record of farming in North America (reaching back 4,100 years), the Tucson Basin has become an international learning lab for how farmers can adapted to the kind of climate shifts that have plagued farmers here for at least 900 years.

That’s one upshot of my new book, Growing Food in a Hotter Drier Land: Lessons from Desert Farmers on Adapting to Climate Uncertainty (Chelsea Green Publishing 2013). For decades if not centuries, Tucson has been an incubator of nursery grounds for new innovations in rainwater harvesting, techniques for shading crops to beat the heat, building soil-moisture holding capacity, and using seed diversity as a bet-hedging strategy. And once again, people from all parts of the world are taking notice.

After centuries of Ak-Chin agriculture and decades of water harvesting experiments in the area, Tucson has once again become one of the global hot spots for training others on how to harvest rain and nutrient-rich floodwaters to produce food. In particular, Tucsonan Brad Lancaster’s Rainwater Harvesting for Drylands and Beyond workshops have helped thousands of Arizona residents break their addiction to groundwater pumping, and inspired tens of thousands of others on three continents to jump into the dance.

Tucson has once again become one of the global hot spots for training others on how to harvest rain and nutrient-rich floodwaters to produce food.

Almost exactly a century ago, Arizona hosted one of the first World Dry-Farming Conferences that focused on desert-adapted seedstocks that could not only take the heat, but survive drought. Today, with home-grown desert heirloom seed sources like Native Seeds/SEARCH, Aravaipa Heirlooms, Desert Survivors Nursery and the Pima County Public Libraries’ Seed Library program in place, gardeners and farmers in Southern Arizona are once again well-positioned to use crop diversity to help buffer their production from uncertainty.


Gary Paul Nabhan’s Growing Food In A Hotter, Drier Land

But on-farm biodiversity doesn’t end with what grows in the rows. Arbico Organics in Oro Valley has become a world leader in sourcing beneficial insects and soil inoculants containing diverse effective microbes. To the southeast of Tucson, Petey Mesquitey’s Spadefoot Nursey and Borderlands Restoration L3C are providing dozens of farmers and gardeners with pollinator-attracting plants for hedgerows that keep the birds and bees which increase crop yields. At ReZoNation Farm near Marana, Jaime de Zubeldia is providing natural beekeeping workshops to ensure that there are enough pollinators around to make use of those fragrant nectar plants.

At Avalon Organic Gardens near Tubac, Tarenta Baldeschi has devised a half dozen strategies to shade and buffer greens and veggies from extreme summer heat. Another 30 miles to the north, at Bean Tree Farm near the upper end of the Tucson Mountains, permaculture designer and wild forager Barbara Rose has trained hundreds of residents in how to design their land uses to enhance the bounty of both wild and cultivated edibles. And further on up the road—off Highway 101 on the Salt River Indian Reservation—Ken Singh is demonstrating to hundreds of Arizonans each week how to build moisture-holding capacity on his two acres of compost-rich gardens and orchards at Singh Farms. Due to his diligent use of effective microbes and organic feedstock for his compost, Ken has achieved 25-foot growth of fruit trees in less than eight years, and increased moisture capacity of his soils at least tenfold.


Urban harvesting of cactus fruit.

Curiously, since the 1950s, the urban heat islands of Metro Tucson and Phoenix have been warming up faster than the state and global averages for temperature increases. Varieties of fruit and nut trees which grew well here 40 years ago no longer receive enough “chill hours” in the winter for adequate flowering and fruiting. And so, Jesus Garcia of the Kino Heritage Fruit Trees Project has worked with nurseries to make available “low chill” heritage varieties of figs, quinces, pomegranates and grapes that still produce abundant and delicious fruits after mild winters.

The take home message of Growing Food in a Hotter Drier Land is not only simple, but reassuring: We need not be passive victims of accelerated climate change. By considering the food choices we make each day, and by supporting the sustainable ways in which our food is produced nearby, we can help shrink our “carbon foodprints” and adapt to the new normal.

Gary Paul Nabhan is an internationally celebrated nature writer, food and farming activist, and proponent of conserving the links between biodiversity and cultural diversity.

Adapting to the New Normal

As we deal with the inevitable impacts of climate change on our food system, there are several key principles that we should embrace and adapt to our own conditions:

•   As much as possible, harvest rainwater and the nutrient-rich organics that flow from the desert into our gardens and fields.

•   Do everything possible to improve soil moisture holding capacity by composting with locally sourced materials.

•   Use the strategies of biomimicry to “think like a desert oasis” to design nurse plant guilds of desert-adapted food crops.

•   Increase the efficiency of water delivery all the way to the plant roots; become a water conservation plumber.

•   Welcome into your garden or orchard a diversity of plants, beneficial insects and soil microbes to be “co-farmers” with you, to create greater resilience in your foodscape.

•   Savor the intense flavors of the desert. As Wallace Stegner once challenged all Westerners to do: “get over the color green.” ✜

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