Effect of Long-Term Sagebrush Litter Manipulation at the Reynolds Creek Experimental Watershed on Foliar Carbon and Nitrogen
Faculty Mentor Information
Dr. Marie-Anne de Graaff, Boise State University; and Arden Engel, Boise State University
Presentation Date
7-15-2026
Abstract
Climate change alters plant-microbe mediated carbon cycling between the atmosphere and soil, Earth’s largest terrestrial carbon pool. Plants convert atmospheric CO₂ into organic litter, while microbial decomposition returns carbon to the atmosphere. Since these exchange rates vary with climate, it is uncertain how climate-driven changes in litter production affect soil carbon sequestration. We investigated this at the Reynolds Creek Experimental Watershed (RCEW) in the Great Basin, dominated by Big Sagebrush (Artemisia tridentata), evaluating how foliar carbon (C%) and nitrogen (N%) concentration in sagebrush leaf-litter responded to 12 years of annual manipulation of litter input quantity. 18 plots were constructed around mature sagebrush and assigned one of three annually-applied treatments: control, no-litter (aboveground litter removed), or double-litter (proportionally allocated additional litter removed from no-litter plots). Foliar C and N impact litter’s vulnerability to decomposition and host shrub health. We hypothesized foliar N concentration in no-litter plots would decrease as the size of the N pool was reduced through removal of N-containing litter. While we observed no significant changes in foliar C or N concentration or in shrub biomass index between litter treatments, slow nutrient cycling in dryland systems may necessitate longer-duration manipulation to detect differences. Anecdotal visible health differences between double-litter and no-litter shrubs suggest that additional quantification of the total N pool in each shrub may provide more nuanced insights. These findings will help refine the parameters used in climate models to more appropriately model the influence of plant productivity on soil carbon storage and nitrogen cycling.
Effect of Long-Term Sagebrush Litter Manipulation at the Reynolds Creek Experimental Watershed on Foliar Carbon and Nitrogen
Climate change alters plant-microbe mediated carbon cycling between the atmosphere and soil, Earth’s largest terrestrial carbon pool. Plants convert atmospheric CO₂ into organic litter, while microbial decomposition returns carbon to the atmosphere. Since these exchange rates vary with climate, it is uncertain how climate-driven changes in litter production affect soil carbon sequestration. We investigated this at the Reynolds Creek Experimental Watershed (RCEW) in the Great Basin, dominated by Big Sagebrush (Artemisia tridentata), evaluating how foliar carbon (C%) and nitrogen (N%) concentration in sagebrush leaf-litter responded to 12 years of annual manipulation of litter input quantity. 18 plots were constructed around mature sagebrush and assigned one of three annually-applied treatments: control, no-litter (aboveground litter removed), or double-litter (proportionally allocated additional litter removed from no-litter plots). Foliar C and N impact litter’s vulnerability to decomposition and host shrub health. We hypothesized foliar N concentration in no-litter plots would decrease as the size of the N pool was reduced through removal of N-containing litter. While we observed no significant changes in foliar C or N concentration or in shrub biomass index between litter treatments, slow nutrient cycling in dryland systems may necessitate longer-duration manipulation to detect differences. Anecdotal visible health differences between double-litter and no-litter shrubs suggest that additional quantification of the total N pool in each shrub may provide more nuanced insights. These findings will help refine the parameters used in climate models to more appropriately model the influence of plant productivity on soil carbon storage and nitrogen cycling.