Academic Level at Time of Presentation
Graduate
Major
Agricultural Science
Minor
Soil Science
List all Project Mentors & Advisor(s)
Iin Purwati Handayani
Presentation Format
Poster Presentation
Abstract/Description
Alfisols and Ultisols are two important soil orders widely distributed across the United States, particularly in agricultural regions. Alfisols are generally mature soils, whereas Ultisols are more strongly weathered and leached. Differences in soil development and mineralogy may influence soil color, organic carbon (SOC), aggregation, and structural stability. This study compared SOC in dark- and light-colored agricultural soils and examined its relationship with aggregate-size distribution. Soil samples were collected from agricultural fields at four locations in western Kentucky and Stewart County, Tennessee, USA. Soil color was determined using the Munsell Soil Color Chart, SOC was estimated by loss on ignition (LOI), and macroaggregates and microaggregates were quantified by wet sieving. Significant differences in SOC between dark- and light-colored soils were observed in 75% of samples. The highest estimated SOC concentration occurred in dark soil from Doran Arboretum, Kentucky at 8.8%, followed by West Farm 7%. Across the samples, macroaggregates were 50% more abundant than microaggregates. The most degraded soil as indicated by the lowest structural stability was found in light soil of Calloway county at 1% and the best soil structural stability was found in dark soil from Stewart County at 52%. These findings suggest that soil color, alongside SOC, may help indicate differences in aggregate-size distribution and soil physical condition. Such indicators could support monitoring of soil carbon dynamics, erosion risk, and soil resilience to climate-related stresses, informing climate-smart agriculture and sustainable soil management.
Fall Scholars Week 2026
Research Poster Competition and Presentations, Soil/Crop Management (Agriculture) and Sustainability
How is the Relationship among Soil Organic Carbon, Soil Color and Structural Stability in Alfisols and Ultisols?
Alfisols and Ultisols are two important soil orders widely distributed across the United States, particularly in agricultural regions. Alfisols are generally mature soils, whereas Ultisols are more strongly weathered and leached. Differences in soil development and mineralogy may influence soil color, organic carbon (SOC), aggregation, and structural stability. This study compared SOC in dark- and light-colored agricultural soils and examined its relationship with aggregate-size distribution. Soil samples were collected from agricultural fields at four locations in western Kentucky and Stewart County, Tennessee, USA. Soil color was determined using the Munsell Soil Color Chart, SOC was estimated by loss on ignition (LOI), and macroaggregates and microaggregates were quantified by wet sieving. Significant differences in SOC between dark- and light-colored soils were observed in 75% of samples. The highest estimated SOC concentration occurred in dark soil from Doran Arboretum, Kentucky at 8.8%, followed by West Farm 7%. Across the samples, macroaggregates were 50% more abundant than microaggregates. The most degraded soil as indicated by the lowest structural stability was found in light soil of Calloway county at 1% and the best soil structural stability was found in dark soil from Stewart County at 52%. These findings suggest that soil color, alongside SOC, may help indicate differences in aggregate-size distribution and soil physical condition. Such indicators could support monitoring of soil carbon dynamics, erosion risk, and soil resilience to climate-related stresses, informing climate-smart agriculture and sustainable soil management.