Location: Range and Meadow Forage Management Research
Project Number: 2070-21500-001-016-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jul 1, 2026
End Date: Sep 30, 2028
Objective:
Soil carbon dynamics is an active field of research across the world as we attempt to identify how much carbon is sequestered and stored within our ecosystems across space and time. This is an especially key topic of discussion and research within dryland ecosystems where moisture limits microbial processes that drive carbon and nutrient cycling provides essential resources for plant growth. However, within our drylands, plant community composition and cover, along with soil biogeochemical cycling are extremely heterogeneous across regional and local scales. Within the sagebrush steppe 1.3 million acres are being converted to annual grasses which could result in a loss up to 50% of soil organic carbon from within the soil profile. The loss of soil organic carbon starts a cascading effect of losses in soil health and co-benefits like water holding capacity, nutrient cycling, erosion protection, and ultimately forage production. The heterogeneity of our soils and plant communities make it difficult to adequately sample soils and to understand how carbon is cycling, but also how other nutrients influence the carbon cycle.
Geospatial mapping of soil map units and vegetation classes has made it possible to more adequately design soil sampling strategies, but we are still limited in our ability to process and analyze soils across 1,000's of acres because our understanding of how carbon and other nutrients cycle at fine scales (square meters) in drylands is limited, along with how native plant functional groups influence that cycling. Our overarching objective is to determine how a range of ground covers, including bare and moss, influence carbon and nutrient cycling beneath dominant sagebrush steppe plant functional groups. Specifically, we will determine where soils should be sampled for carbon and soil health metrics in sagebrush steppe rangelands, and how the variability within microsites and microclimates influences the overall carbon and nutrient dynamics of sagebrush rangelands.
Approach:
Sampling soils and understanding and studying the biogeochemical processes and mechanisms underlying carbon storage and sequestration appears to be a simple task until we recognize the enormous local heterogeneity in dryland rangelands driven by the patch mosaic nature of vegetation cover and land management practices. Using sub-meter precision GPS, plant and biocrust monitoring, and land management history we can optimize our soil sampling designs to capture how different plant functional groups influence soil nutrient cycling. Our USU cooperator has the expertise, skilled laboratory technicians, and laboratory instruments necessary to support key biogeochemical analyses to aid in understanding how different microsites (beneath live or dead sagebrush, near large perennial bunchgrasses, open interspace) influence the biogeochemisty of our sagebrush rangelands. These carbon and nutrient cycling data will then be coupled with microclimate monitoring sensors to better understand the mechanisms for nutrient cycling and priming the sagebrush plant community for the growing season.