Growing lessons from the desert

by Ari LeVaux

Recent years have brought spikes in the frequency of strange weather and severe storms, with many blaming the increase on human-caused climate change. If this new normal is here to stay, it will have profound implications on food production.

There are two basic ways this threat is being addressed. One is to develop new crops and agricultural methods to withstand heat and drought stresses. The other is to look to the past for solutions; at crops and techniques used in regions that have historically endured this kind of weather. A new book by ecologist Gary Paul Nabhan, Growing Food in a Hotter, Drier Land, is an exploration of the latter approach.

Nabhan lives in the Sonoran desert of Mexico, along the border with Arizona. His quest to understand the farming systems of the world’s driest places has taken him to the Sahara, Gobi and Taklamakan, among others. He has studied how inhabitants of these places grow food in thin soils, where long droughts are punctuated by violent rains that can wash away topsoil and drown plants. His book presents numerous examples of farmers doing what seems impossible, and documents their primitive and effective techniques for blocking the wind, recovering fertile silt from runoff, shading dwellings, and capturing rain water.

Crop diversity is central to Nabhan’s concept, offering options in case some crops fail and increasing yields. One classic polyculture of the Southwest, known as the “Three Sisters,” consists of corn, squash and beans. It’s possible there are others that could prove valuable as well. “Few seed catalogs explicitly tell us which heirloom varieties have been selected and adapted for inclusion in intercrops or polycultures. We must do our own on-farm description, selection and evaluation of annual seed crops to determine how we can put the pieces of the puzzle back together,” Nabhan writes.

It is his reverence for diversity, rather than distrust of science, that makes him question the value of modern agriculture that seems obsessed with polyculture’s polar opposite: monoculture.

“We could evaluate adaptations and drought tolerance of 10,000 heirloom, seed varieties for the price of developing and patenting one new GM crop,” Nabhan told me by phone.

Clearly, farmers in dry regions could have much to learn from this book, but what about those who live in cities or regions that aren’t dry, or don’t have any interest in growing their own food? I asked Nabhan if his book has value for them.

“In the last few years we’ve had drought disasters as far east as Illinois and Indiana,” Nabhan told me. “The techniques I’ve gleaned from desert farmers are now applicable to two-thirds of the continent.”

As for nonlandowners, strategies like growing short-cycle crops during the rainy season can be done on any scale, from garden to field. Community gardens could employ them as well, he added.

The book also contains information for the largest category of potential readers – those whose thumbs are no greener than the money they use to buy food. Consumers have grown accustomed to thinking about how far their food has traveled, and Nabhan deserves his share of credit for inspiring the locavore movement with his 2001 book Coming Home to Eat: The Pleasures and Politics of Local Foods. But while terms like “food miles” have worked their way into the vernacular, the idea of “embedded water” – i.e. the amount of water needed to produce something – is less common.
“Compared to the water each of us drinks each day – 1 to 1.3 gallons – there is 3,250 times the amount embedded in the food we eat,” Nabhan writes. For instance, 600 gallons are embedded in a single cattle feedlot.

Longer, hotter summers will increase evaporation while changing weather will make that moisture’s return to earth harder to predict. Since food accounts for a large share of the water we use, our eating habits have a huge impact. While farmers in hotter, drier climates will need to adapt, consumers can respond by learning about the embedded water in the foods they buy.

Among the most water-thrifty crops, according to Nabhan’s book, are beans, peas and cabbage. Melons are nearly as water-wise. Nabhan tells the story of a Mexican farmer who put three children through college by growing watermelons in the desert of northern Chihuahua. The farmer irrigated his melons with hauled water that he used to fill buried clay pots, which slowly released water to the roots. A similar technique is used in the deserts of Central Asia and Northern Africa.

It isn’t clear whether this method was imported to the Americas or evolved here. Human ingenuity is as universal as the conditions that inspire it. In the face of a new normal, this ingenuity could be key to keeping us fed. The examples in this book give reason to believe we can navigate the tricky conditions that appear to be coming our way.