RENO, Nev. — Scientists at the University of Nevada-Reno have found that targeted cattle grazing during the dormant season can help control cheatgrass, an invasive annual grass responsible for increasing wildfire danger in the Intermountain West.

Researchers say cheatgrass is an “ecological threat” in the Western U.S., dominating more than 20% of the sagebrush steppe and covering about 11,000 square miles of the Great Basin, according to a new study in Elsevier’s journal Rangeland Ecology and Management.

“We’re facing challenges right now in sagebrush rangelands the likes of which nobody’s ever seen,” Chad Boyd, a rangeland scientist with USDA’s Agricultural Research Service, told the Capital Press. “I mean, when you look at the annual grass problem, when you look at the tens upon millions of acres that it impacts West-wide, nobody’s ever faced a problem that big.”

To combat infestation, researchers have been studying use of off-season targeted cattle grazing as a tool for reducing cheatgrass.

University of Nevada-Reno researchers have found that an effective method for getting cattle to graze in cheatgrass-invaded systems involves setting up supplemental protein feeding stations near areas with fine fuel buildup. Drawn to the feeding stations, cattle also eat nearby cheatgrass.

According to Barry Perryman, professor of rangeland sciences at the university and an author of the study, putting out protein supplements in the fall and early winter can attract cattle to locations dominated by cheatgrass. The cattle then reduce standing fine-fuel biomass by more than 50%, he said. That makes room for native grasses to grow.

In turn, this can potentially reduce wildfire danger.

“Reducing the amount of cheatgrass fuel carryover may effectively reduce the amount of total fuel available during the next year’s fire season,” said Perryman. “If several hundred pounds per acre of cheatgrass can be removed during the fall through cattle grazing, that is several hundred pounds that will not be added to the next year’s fuel load.”

Perryman’s conclusions build on previous studies.

One small-scale study showed that targeted grazing during spring can reduce above-ground biomass by 80% to 90%, resulting in reduced flame length and rate of fire spread the following October. Another study, done on sagebrush and native perennial grass plant communities, found that reducing biomass by 40% to 60% through winter grazing reduced flame height, rate of spread and area burned compared to a control area that was not grazed.

For the new study, Perryman and the scientists he worked with used liquid protein supplements in October and November from 2014 to 2017 at a production-scale working ranch with a herd size ranging from 650 to 1,200 head of cattle.

The pasture the researchers experimented on was a mixture of rangeland and abandoned farmland heavily invaded by cheatgrass.

The study found that protein supplements can successfully attract cattle away from water toward cheatgrass-infested areas on large pastures.

Where cattle grazed along the transect line of the supplemental feeding stations, their consumption of cheatgrass averaged 48% to 81%.

Besides Perryman, other authors on the study included Mitchell Stephenson, who was a post-doctoral student of Perryman’s during the study and is now a range management specialist at the University of Nebraska-Lincoln; Brad Schultz, professor and extension educator at the University of Nevada-Reno; and Chad Boyd, Kirk Davies and Tony Svejcar, rangeland scientists with USDA.