From KVNF (Jodi Petersen) via KUNC:
[A.J.] Carrillo is planning to convert his Deer Tree Farm from flood irrigation, which is commonly used in Western Colorado, to a new and much more efficient style of irrigation – microsprinklers.
Changing irrigation methods is something more and more Western Slope producers are doing, from small to large. With help from federal funding, they’re able to apply less water to grow their crops and make their land more resilient to drought. And more importantly, the switch also means that fewer pollutants run off their fields into the Colorado River, keeping it cleaner all the way down to Mexico.
Salt and selenium occur naturally in the shaly soils of the Gunnison Basin, leftovers from a prehistoric inland sea. Both substances are harmful to plants, fish and humans. Flood irrigation of fields allows water to penetrate deep into the soil, where it dissolves out salt and selenium.
The contaminated water then runs off into ditches that eventually dump into the Gunnison River, and from there into the Colorado. The result is that farms in the Gunnison Basin send more than 360,000 tons of salt into the Colorado River each year…
All that salt must be removed before water can be used for drinking or industrial purposes, which is expensive. And when salty river water is used for irrigation, it stunts crop growth and can eventually make farmland unusable if the salt builds to a high enough concentration, said Perry Cabot, a water resources specialist with Colorado State University…
In California’s Imperial Valley, which grows about 80 percent of the nation’s winter vegetables, irrigating with Colorado River water has caused some fields to become so salty that they have been abandoned.
Selenium is a problem too. It’s especially harmful to the Colorado River’s four endangered fish species, including the humpback chub and razorback sucker…
The same actions that reduce selenium – improving irrigation efficiency and reducing runoff – help reduce salt as well. And those programs have a far-reaching impact.
During the 1960s, so much salt flowed into the Colorado River from U.S. farms that Mexico, at the downstream end, could no longer use it for irrigation; a solution was finally negotiated in the 1970s requiring major reductions in the river’s saltiness. Laws were passed, and an array of federal program were created that gave farmers incentives to improve their irrigation methods.
Since then, the Colorado has gotten considerably cleaner. Casey Harrison, a soil conservationist who works with farmers through the federal Natural Resources Conservation Service, or NRCS, is part of that cleanup effort. In the Gunnison River Basin, the NRCS spends about $7 million a year to help roughly 75 farmers and ranchers convert to microsprinklers and other efficient irrigation methods.
The NRCS tailors plans to each producer’s operations, Harrison said, no matter how large or small…
The federal financial support is key. The costs of installing new irrigation systems cannot be borne by farmers alone, CSU’s Perry Cabot said. Agricultural producers are running a business, and they do not want to spend tens of thousands of dollars to make a change unless there is some clear incentive.
“If we as a society value food production as part of our economic infrastructure, it’s unrealistic to expect them to just bear the burden without societal help,” Cabot said.
Back at Deer Tree farm, farmer AJ Carillo says the operation will have a new irrigation system by fall 2021, thanks largely to NRCS funding and support. The change to microsprinklers will give him greater precision and control in water use.