JDJCSET | Watershed Studies Institute Research Symposium
How do alluvial landforms affect the storage of soil organic carbon? A case study from humid-temperate western Kentucky
Academic Level at Time of Presentation
Graduate
Major
Geosciences
Minor
n/a
List all Project Mentors & Advisor(s)
Gary E. Stinchcomb
Presentation Format
Oral Presentation
Abstract/Description
Soil organic carbon (SOC) storage in river valley bottoms at depths greater than one meter and the processes that operate on SOC at depth are not well understood. These depths may house large stocks of SOC that so far have been underestimated. Soil texture is understood to be a main control on SOC storage but the role that texture plays at depth is not fully understood. This study examines SOC along two alluvial landforms, a floodplain and terrace, in the Clarks River National Wildlife Refuge. The hypothesis of this study is that soil texture and structure are a primary control on SOC storage at depths greater than one meter in valley bottoms. Preliminary SOC and texture data collected from western Kentucky floodplain soils show a direct correlation between SOC and the percentage of clay; whereas terraces show an inverse correlation between SOC and the percentage of clay. This was tested further by compiling characterization data from 15 western Kentucky pedons using the National Cooperative Soil Survey Soil Characterization Database. SOC and percentage of clay were plotted against each other for upland, terrace, and floodplain soils. The slope of the trend lines, ΔSOC/ΔClay, was determined and compared by group. Only floodplain pedons were observed to have a positive ΔSOC/ΔClay correlation. Preliminary data suggest that texture-dependent storage in floodplains behaves differently than in terraces. Deposition of flood sediment and soil development play an important role in affecting the ΔSOC/ΔClay on floodplains.
Affiliations
Watershed Research Institute
How do alluvial landforms affect the storage of soil organic carbon? A case study from humid-temperate western Kentucky
Soil organic carbon (SOC) storage in river valley bottoms at depths greater than one meter and the processes that operate on SOC at depth are not well understood. These depths may house large stocks of SOC that so far have been underestimated. Soil texture is understood to be a main control on SOC storage but the role that texture plays at depth is not fully understood. This study examines SOC along two alluvial landforms, a floodplain and terrace, in the Clarks River National Wildlife Refuge. The hypothesis of this study is that soil texture and structure are a primary control on SOC storage at depths greater than one meter in valley bottoms. Preliminary SOC and texture data collected from western Kentucky floodplain soils show a direct correlation between SOC and the percentage of clay; whereas terraces show an inverse correlation between SOC and the percentage of clay. This was tested further by compiling characterization data from 15 western Kentucky pedons using the National Cooperative Soil Survey Soil Characterization Database. SOC and percentage of clay were plotted against each other for upland, terrace, and floodplain soils. The slope of the trend lines, ΔSOC/ΔClay, was determined and compared by group. Only floodplain pedons were observed to have a positive ΔSOC/ΔClay correlation. Preliminary data suggest that texture-dependent storage in floodplains behaves differently than in terraces. Deposition of flood sediment and soil development play an important role in affecting the ΔSOC/ΔClay on floodplains.