Dryland - Detritus Input and Removal Treatments (D-DIRT) SAGE: Relating Litter Inputs to Carbon Storage and Climate Change

Document Type

Student Presentation

Presentation Date

April 2017

Faculty Sponsor

Marie-Anne de Graaff


Globally, soil stores three times more carbon (C) than the atmosphere and terrestrial vegetation combined. Therefore, changes in the amount of organic carbon (SOC) stored in soil can affect global atmospheric CO2 concentrations, and either exacerbate or mitigate climate change. Plant litter input to soil is the primary source of SOC, and with climate change, we expect to see changes in the amount of litter input. Yet, accurate predictions of how these changes in litter input impact SOC accumulation are hindered by an incomplete understanding of the processes that drive C accumulation rates, including microbial driven litter decomposition processes. With this study, I ask how changes in litter input to soil affect SOC contents, fungal-to-bacterial ratios and decomposition processes. To address these questions, I collected soils from the Detritus Input and Removal Treatments (DIRT) experimental field site, located at the Reynold’s Creek Experimental Watershed (RCEW), in the Owhyee Mountains (ID). The site was established in 2013, and litter input to soil was manipulated in sagebrush (Artemisia tridentate ssp. wyomingensis) canopy, and intercanopy microsites according to the following design: (1) no litter input (2) double litter inputs, and (3) control (i.e. ambient litter input). These treatments are reapplied annually during late summer. We analyzed each of these plots for total SOC content and preformed a qPCR analysis in order to determine the fungal-to-bacterial ratios of each plot. We expect to see higher fungal-to-bacterial ratios in the double litter plots than in the control and no litter plots. This would indicate that the treatments affect soil C cycling, because fungi and bacteria have differential impacts on C cycling rates.

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