Cheatgrass is an invasive species that greens up and sets seeds earlier than most native species. It uses up soil moisture in the spring, which can prevent the germination of native plants. Studies on managing the invasive species are ongoing in the Panhandle of Nebraska and were part of a Cheatgrass Tour on June 26. Among the tour stops were pastures owned by Banner County Rancher Jack Revelle, which he had treated with Rejuvra.
Miranda Mueller, a graduate research assistant at the University of Nebraska-Lincoln Panhandle Research Extension and Education Center in Scottsbluff, has three studies on cheatgrass management with herbicides.
“We didn’t stop at any of my study sites on the tour, but Jack’s (Revelle) have the same treatment as my five study sites,” she explained. “One study focuses on the efficacy of indaziflam (Rejuvra) compared to a combination of indaziflam and imazapic and compared to a check. The study was aerially treated with herbicide in July 2021. Cover data, dry weight rank, and species frequency data were collected in 2022 and 2023, so this summer will be the third-year post-treatment that data is collected on that site.”
Mueller’s second study consists of five different upland ecological sites that are scattered around Scottsbluff. The sites were all aerially treated with a combination of indaziflam and imazapic in September of 2022. Biomass data has been collected in paired quadrats at all five sites, and differences in species composition, production differences, and forage quality metrics have been determined at each site one-year post-application, and this summer will be the second year of data collection.
“We haven’t been able to analyze any of the data for the third study yet, but it is a greenhouse gas emissions study comparing emissions between invaded range, native range, treated range, and bare range, which are blowouts and are devoid of nearly all vegetation,” she said.
In Banner County, the tour stopped at Jack Revelle’s pastures, where he had yearlings out grazing. He said his yearlings had noted weight gain after the treatment on the pastures, which Mueller is seeing in her data.
“After one year of data collection post-treatment we saw over three times more biomass being produced in the treated areas compared to the untreated areas. We also saw significant increases in important nutrient quality metrics, including crude protein and TDN, along with increases in some micro and macro minerals in the treated areas,” Mueller said.
While the studies are not all complete, there are some things Mueller has already found out. “In study one, adequate moisture is needed after indaziflam application to allow it to enter the soil and do its job as year one after treatment the indaziflam alone treatment showed no significant decrease in cheatgrass frequency compared to the check treatment.”
Her research has also found that after the second year of data collection, the indaziflam alone treatment had a significant difference in cheatgrass frequency compared to the check and also compared to the combination treatment. Still, the indaziflam alone treatment was not as effective as the combination treatment.