Can cacti help San Joaquin Valley farmers survive a drought?


When I finally got a hold of John Diener, the busy 62-year-old farmer was en route to his organic broccoli field in central California's San Joaquin Valley. I could picture the scene: a truck bouncing over a dusty track, golden morning sunlight, rows of bright green plants meeting a blue sky.

The vision was idyllic. But this area, one of the nation’s most agriculturally productive, has a problem: in places, the soil is killing the crops it’s meant to grow. Before a maze of irrigation ditches transformed it into an agricultural belt, the San Joaquin Valley was an ancient seabed, a vast stretch of arid soil high in salt, selenium and boron. Now, decades of irrigation and poor drainage have concentrated the naturally-occurring minerals to toxic levels, and the current drought is only exacerbating the problem without rain to drive them deeper into the water table, the soil is growing even less hospitable.

Even the irrigation water is briny; 57 railroad cars worth of salt are pumped into the valley each day, and environmental concerns prohibit farmers from funneling the wastewater back into rivers and ditches as they once did – meaning the minerals accumulating on their land have nowhere else to go. Roughly 400,000 acres are at risk of becoming unusable because they’re too salty.

Some of his neighbors have taken land out of production, but Diener – who recycles 99 percent of his water and has won national conservation awards – would like to live out his days on the farm his family has worked since the 1920s. “I don’t think of land as a disposable resource,” he says. “I don’t want to sell the farm. So the reality is, what are we going to do to remediate the soil?”

Enter U.S. Department of Agriculture scientist Gary Bañuelos, who’s built a career of figuring out what grows best in some of the world’s worst soils. (Chernobyl cabbage, anyone?) Bañuelos says the worst part of the drought for San Joaquin farmers isn’t that there’s not enough water for irrigation, but that there’s not enough water to leach the minerals out. “If you don’t push the salt out of the roots (with water), the molecules migrate toward the surface and bring the salt with them,” he explains. “That’ll eventually kill the plant.”

At least, it kills most plants. But what if there were a plant that thrived in sodium- and selenium-rich soil? One that required very little water and even improved soil conditions by volatilizing selenium – sucking it up and off-gassing it? After decades of research, Bañuelos has patented four new varieties of just such a plant: Botanists call it opuntia ficus-indica. Hispanic-food lovers know it as nopales. See also: prickly pear cactus.