UNR tests whether cow manure can help restore Nevada landscapes after wildfires

After decades of cheatgrass-fueled wildfires across Nevada, researchers at the University of Nevada, Reno are testing whether cattle can help restore damaged rangelands by spreading native seeds as they graze.

Cheatgrass, an invasive plant common across the Great Basin, dries out early and can fuel larger wildfires, making it harder for native vegetation to return. UNR postdoctoral scholar William Richardson said the plant helps create a self-reinforcing cycle.

“Cheatgrass grows, it creates more wildfires, that allows more cheatgrass to grow, and it becomes a bigger and bigger issue. That’s why we’re seeing all these mega fires spreading across the Great Basin,” Richardson said.

The challenge continues after flames are out. In Nevada’s arid climate, native plants can struggle to reestablish, while cheatgrass often returns quickly.

“We struggle with getting five to eight inches of rain a year. Trying to restore a native community in those very arid conditions are extremely difficult,” Richardson said.

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Ranchers already use targeted grazing to reduce cheatgrass. Now, UNR researchers are studying whether cattle can also help reseed the landscape. The approach mixes native grass seeds into protein supplements cattle already eat. Researchers then track whether the seeds can survive digestion and be spread naturally across the range after being deposited in manure.

“We’re already using cattle to combat cheatgrass through targeted grazing, and the ultimate goal is to bring native species back across the landscape, so why don’t we combine those two ideas?” Richardson said.

In lab testing, researchers evaluated special seed coatings designed to help some seeds survive a cow’s digestive system. The results showed certain species could make it through the process and still germinate after being deposited in manure, Richardson said, though some seeds need more protection than others.

UNR tests whether cow manure can help restore Nevada landscapes after wildfires

“Some species naturally have a very thin seed coat and require more protection, while others can go through the gut of a cow easy peasy lemon squeezy,” he said.

The project is expected to move into field testing this fall at Horseshoe Ranch near Eureka, where researchers will track whether seeds can not only survive digestion but also establish new plants on the landscape.

“It’s a passive way to restore the landscape. Instead of having to go in with a tractor or seed from an airplane, you can use cows that are already there,” Richardson said.

UNR tests whether cow manure can help restore Nevada landscapes after wildfires

Researchers said the method is not intended to replace traditional restoration work, but to add another tool for land managers and ranchers. If the field trials are successful, they said the approach could eventually help restore thousands — or even hundreds of thousands — of acres across the Great Basin.