Could Climate Change Put an End to Arizona’s Alfalfa Heyday?

It’s always alfalfa season in Arizona. In most other parts of the country, the perennial crop grows tall enough to harvest just a few times a year. But in the sun-drenched Southwest, the irrigated fields allow the crop to grow year-round, to the tune of 8.5 tons harvested for every acre and $397 million a year. All farmers need to do is add water.

At least that’s been the case for the many decades that alfalfa has boomed and bloomed in the Arizona desert, providing feed to the region’s megalithic dairy industry. Now, accelerating climate change and depleting water availability could change this.

As the Colorado River has reached historically low levels this summer, the future of Arizona’s water-thirsty alfalfa and irrigated agriculture has been called in to question. In August, federal officials declared the first-ever water shortage in Lake Mead, one of the two giant reservoirs fed by the river. This triggered mandatory water cuts outlined in a 2019 plan to prevent further, more dangerous drops in water. Arizona faces the sharpest cut: 18 percent of the state’s share of the water will be reduced in 2022, compared to 7 percent for Nevada, 5 percent for Mexico, and no reductions for California.

This initial cut will almost entirely affect farms in the state. It will reduce 65 percent of the water used by farmers who rely on the Central Arizona Project (CAP), which channels water to the Central Arizona counties of Maricopa, Pinal, and Pima. This will likely lead to significant changes in these counties, where many farmers grow massive fields of cotton and alfalfa in rotation.

Stephen Miller, a district supervisor for Pinal County, said cuts could have a “catastrophic impact on Pinal County’s agricultural community,” adding that it will be up to farmers to determine how they adjust to these changes. “Farmers will need to identify alternative methods of securing water which will vary from additional groundwater pumping to transporting water from secure water sources outside of Arizona,” said Miller.

And yet if the region’s historic drought continues, as climatologists project it likely will, farmers will also likely fallow alfalfa fields and consider making a switch to other, less water-intensive crops. Such a transition, however, could also require reconfiguring the interlocking relationship between Arizona’s dairy industry and the alfalfa that has long been embedded in the state’s food economy.

Cattle Crops Are Draining the Colorado River Basin

Alfalfa has been praised for being a drought-resilient crop, able to withstand the heat of the Arizona sun. Yet, there is no way to get around the fact that it requires an immense, increasingly untenable quantity of water. In the western U.S., irrigated crops fed to cattle—alfalfa, grass, and corn silage—are the largest consumer of river water, according to a study in Nature Sustainability. The authors found that nearly half of the Colorado’s water goes to irrigating cattle crops, with 32 percent going to alfalfa. A dairy cow requires a lot of indirect water, consuming 50 to 55 pounds of dry feed per day, by one estimate.

“If you’re going to work your way out of a water shortage in the West, one of the first things you want to pay attention to is where most of the water is going,” said Brian Richter, the lead author on the study and the president of Sustainable Waters. “That’s going to lead you to the producers of cattle feed crops.”

The daunting question is how to transition away from cattle feed crops, ingrained in the history, livelihoods, and food supply chains of Arizona and the U.S.

Alfalfa’s expansion in Arizona coincides with waves of colonization. It was first brought to Mexico and South America by way of 16th century Spanish missionaries, who later introduced it to the southwestern United States. During the Gold Rush, beginning in 1848, as European settlers moved into the West, new varieties of alfalfa were brought to the region, explained Michael Ottman, an agronomist in the school of plant sciences at the University of Arizona. In the 1950s, “the modern period of more purposeful plant breeding and selection,” as Ottman called it, alfalfa was especially bred to resist diseases and insects.

Over the past two decades, the dairy industry has expanded by nearly 5 percent in Arizona, creating a growing market for local alfalfa. Dairies are often found near alfalfa fields, given that alfalfa is a bulky crop and transporting it can be costly. They spread together “like rings of water” as one University of Arizona report said to describe the concentrated dairy industry and its input markets, such as alfalfa.

Some dairies grow their own alfalfa to control their supply, including the mega-dairy Riverview LLP, which was found to be draining southeastern Arizona’s groundwater, pockmarking the desert with wells 1,000 feet deep. Other dairies have long-term contracts with farmers to maintain a supply of the herb that his highly nutritious for cows, and therefore, generally considered indispensable.

“[Alfalfa] helps stimulate the rumen. [The dairy industry] has to get it from somewhere,” said Ottman. If Arizona farmers grow less alfalfa while the dairy industry remains in the state, Ottman predicts dairies will start trucking in hay from Idaho, California, Utah, or New Mexico, at a steeper cost.

While Ottman and other experts Civil Eats spoke to don’t see alfalfa going away entirely in Arizona, they expect the crop’s footprint to shrink. John Fleck, a former science journalist and the director of the water resources program at the University of New Mexico, put it this way: “It’s the dominant crop. There’s less water, so there’s going to be less acreage irrigated and alfalfa will shrink.”