Cheatgrass management researched
Published on April 11, 2020
“Managing cheatgrass in rangelands and pastures is a perpetual, widespread problem that has been increasing over time,” states Dr. Mitchell Stephenson, assistant professor of range and forage sciences at the University of Nebraska-Lincoln (UNL) during the university’s Beefwatch podcast.
During the April 1 episode of the university’s podcast, Stephenson notes he is personally interested in managing cheatgrass through targeted grazing.
Targeted grazing research
“Targeted grazing is the application of grazing animals at a specified time and intensity to achieve a particular vegetation outcome,” he explains. “We are currently doing a joint research project on this concept with USDA Agriculture Research Service (ARS) in Cheyenne.”
Stephenson further explains the team has been working on this research for the past three years, which includes tracking cheatgrass consumption of cattle early in the grazing season until cheatgrass has reached its maturity.
“We try to get cattle out grazing cheatgrass when the plant is about two inches tall, which is usually around mid to late April,” he notes.
Stephenson says their study was also set up to look at when cattle were choosing to graze cheatgrass versus perennial cool-season grasses such as needle and thread and western wheat.
“We mapped out biomass and several other measurements throughout the pastures we were grazing during the entire growing season,” he explains.
Research findings
“The first thing we’ve found over these past three years, is plant phenology of cheatgrass varies from year to year,” Stephenson states. “In 2018, the cheatgrass was pretty quick to mature, so it was fairly mature while we were grazing in June.”
Stephenson notes, on the other hand, 2019 exhibited cooler temperatures in late May and early June, so cheatgrass didn’t reach maturity until after the fourth of July.
According to Stephenson, the second thing their research found is there are windows of time when cattle graze cheatgrass more readily.
“We know cattle are consuming perennial grasses, but we think they are grazing cheatgrass as well,” he says. “Therefore, we are using relatively new technology to study this. We go out, collect fecal samples twice a week then send them to a lab in Colorado. The lab is able to pick up on what they are eating, and we are able to learn more about our cattle’s diets in a non-invasive way.”
Stephenson then notes, based on the height of the plant and the days after flowering, they will be able to predict the windows of time cattle choose to graze cheatgrass.
“This will allow us to help cattle producers know when the best time to go out and target cheatgrass with a high-intensity type grazing situation is,” he states
Stephenson continues, “Another thing we are doing is collecting seed biomass at the conclusion of each year, and we found we have been reducing seed biomass by nearly 50 percent where grazing is occurring.”
Other control methods
In addition to their targeted grazing research, Stephenson says the UNL team has also been researching the effectiveness of herbicides in cheatgrass management.
“One of the main options on the market is Plateau, which is fairly well known and has been used in a number of different situations across the West for quite a while,” explains Stephenson. “With our trials, we have had pretty good control in the first year but by the second year we are not pleased with it.”
He points out other areas have had better success depending on the soil type and climate.
“Recently, we have been working with Esplanade, which is available on the market, but there are still some grazing restrictions on it,” he explains. “We have used it in our plots for two years and have been really pleased with the results.”
He notes research in Wyoming and Colorado has also shown positive results in Esplanade’s ability to keep cheatgrass from coming back year after year.
“A few years back there was also some interest in using biocontrol to manage cheatgrass,” Stephenson says. “The research looked at increasing certain types of bacteria that are natural in the soil in hopes they would control cheatgrass on rangelands.”
He continues, “In our research, we found this was not an effective method. In fact, we didn’t see any reduction in cheatgrass at all. There have been some recent publications from different areas in the West that came to the same conclusions.”
Because herbicides are expensive, Stephenson suggests if producers choose to go this route they should use the chemical on a small area first to see how it interacts with their plant community.
“The most important thing producers need to consider is what the dominant species in their fields are, whether that is a perennial grass or cheatgrass, and manage for those species,” he says. “Chemicals are generally easier to implement and they work well. Targeted grazing is a challenge, but I also think it can be a very valuable resource.”
Hannah Bugas is the assistant editor for the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.
