As global warming projections grow more urgent and drought conditions tighten across the American West, finding crops that can survive — and even help — in an increasingly dry landscape has become a serious scientific priority. A University of Nevada, Reno researcher believes a familiar desert plant may hold surprising answers to some of agriculture’s most pressing challenges.
John Cushman, a professor in the Department of Biochemistry, Molecular Biology & Biotechnology at UNR, has spent nearly four decades studying how plants manage water. His current focus is on the spineless pear cactus — known scientifically as Opuntia — a close relative of the prickly pear found across Nevada. Cushman and his colleagues are investigating whether this drought-tolerant plant could serve as a practical alternative to alfalfa as livestock feed, while also offering potential as a biofuel source and a tool for capturing atmospheric CO2.
The research is funded by the U.S. Department of Energy, the Western Sustainable Agriculture Research & Education program, and the Nevada Agriculture Experiment Station. Cushman has filed patents on several of his findings.
A Water Problem That Won’t Wait
Nevada is the driest state in the country, and 100 percent of its agriculture depends on irrigation. That reality shapes everything Cushman does in his lab.
“We are focused on the development of alternative crops that are going to do well in the driest state in the United States, and also the fact that 100 percent of all agriculture in the state requires irrigation,”
Cushman said.
“That means we want to work on plants and crops that use less water. That’s what I’ve been working on all my career.”
Alfalfa has been the dominant livestock feed in the West since the Gold Rush era, and it remains widely used today. But it comes at a steep cost: growing alfalfa requires a lot of water — typically between 8 and 12 acre-feet per year. By comparison, Opuntia requires only about two acre-feet annually, roughly one-sixth the water demand.
“But if you grow Opuntia, it’s about two — and that’s a one-sixth water requirement,”
Cushman explained.
Slow-Growing? Not in a Farm Setting
One common assumption about cactus is that it grows slowly — and in the wild, that’s largely true. But Cushman says the picture looks very different under agricultural conditions.
“This is the common view. In their natural environment, people look at that and see they’re very slow-growing, which is true. However, we focus on an agricultural setting, and that’s very different,”
he said.
On an annual basis, researchers have found that Opuntia produces the same volume of biomass as alfalfa — with six times greater water efficiency. To identify which varieties perform best across different climates, the team has planted 240 varieties of pear cactus in replicated fields across Nevada, California, Arizona, Texas, and Florida.
The plant’s paddle-shaped stems, called cladodes, and its fruit are already appearing in supermarkets. Beyond food and feed, Opuntia can produce methane and ethanol, opening the door to its use as a biofuel feedstock — similar to how corn and soybeans are used today.
“We’re pretty limited right now in the expansion of biofuel production. It’s going up slowly, but if we really want to switch over to biofuels, we need to expand the feedstock. And the only way to do that is to start looking at these arid regions. And Opuntia is really a good choice for that because it requires so much less water. The Western United States is predicted to get about 15 percent drier than it is now, and we’re already seeing that with the extended drought episodes that we’re experiencing,”
Cushman said.
A Carbon Capture Bonus
Beyond water savings and biofuel potential, the pear cactus uses a specialized form of photosynthesis that pulls CO2 directly from the atmosphere — a characteristic that has caught Cushman’s attention as a possible tool for carbon sequestration.
“We’re really interested in water-saving, but also, can we use this as a carbon sequestration crop?”
he said.
Cushman, who first began studying plant water efficiency during postdoctoral research at the University of Arizona and later in Oklahoma, is now in his 26th year at UNR. He views Nevada’s landscape as a natural field laboratory for this kind of work.
Millions of acres of alfalfa across the United States are not going to be replaced by pear cactus overnight. But the research opens a window into what may be possible as the West confronts a drier future — and points to the value of continued investment in agricultural science focused on water efficiency and sustainability. To support independent coverage of issues like this, you can learn more about membership at the Nevada Independent.
