The sprawling, 1,527-acre Shirley Basin South, Wyoming, Disposal Site sits within rolling grassland and sagebrush steppe about 60 miles south of Casper. A uranium mill at the Shirley Basin site processed uranium ore from the 1960s to the 1980s, and a disposal cell on the site now safely encapsulates the radioactive tailings produced in the milling process, as well as contaminated soils and building materials from the old mill.  

The site, which is owned and managed by the U.S. Department of Energy Office of Legacy Management (LM), has supported a grazing licensee as part of the LM Beneficial Reuse Program, which aims to “sustainably manage and optimize the use of land and assets.” 

The Shirley Basin South site is now taking that commitment to sustainable management a step further by hosting a study designed to explore a holistic livestock grazing approach called “regenerative grazing.” 

Site and program managers say the land use history of the site makes it the ideal location for study of sustainable rangeland practices.   

“The Shirley Basin area is very unique — there are a lot of things going on with land use, historically and current,” said David Holbrook, the lead ecologist for the LM Strategic Partner (LMSP). “It’s sort of like a checkerboard. Part of it has been mined before, and it’s been revegetated under a legacy management cleanup. Some of it is native rangeland, and all these areas have different levels of plant diversity. Some areas have been grazed for over 100 years, some for the past 10-20 years, and some that have never been grazed.” 

Holbrook said the unique characteristics of the site will allow a comparison of historic and current land use and livestock practices on plant diversity, soil carbon, and overall rangeland conditions. According to Holbrook, practicing sustainable grazing practices — “the right amount of cows in the right area for the right amount of time” — can promote plant growth and increase the soil’s ability to pull carbon from the atmosphere and store it in the soil, a process called carbon sequestration. 

Carbon sequestration is often promoted as a method of reducing the amount of carbon dioxide in the atmosphere with the goal of reducing global climate change. 

LM already conducts rangeland health monitoring at the site, so it wasn’t difficult to take monitoring one step further into the research realm.