See more from this Session: Soil Genesis and Classification: I (Includes Graduate Student Competition)
Wednesday, October 19, 2011: 9:00 AM
Henry Gonzalez Convention Center, Room 006D, River Level
The central concept of Vertisols focuses on soils with high expanding clay content that shrink and swell with varying moisture conditions. Whereas, Mollisols by definition are mineral soils with high organic matter content, to deeper depths, dark colors in the surface horizons, and high base saturation. Due to the to the process called “pedoturbation” in Vertisols, surficial material with high organic carbon (SOC) content falls into the deep desiccation cracks during the dry season, then mixing with the subsoil due to a churning movement developed by the swelling of the clays on rewetting. This special, ”self-swallowing” process enhances the accumulation of SOC in greater depth in Vertisol profiles, and thus can result in the accumulation of significant amount of stable, sequestered carbon in the subsoil that is unlikely to be affected by natural or anthropogenic factors. The objective of this study was to reveal the significance of pedoturbation in SOC sequestration by analyzing the vertical distribution of SOC in typical Vertisol and Mollisol profiles of Texas and Hungary. These data were selected from the USDA-NRCS soil characterization database and the Hungarian TIM database by local experts. Our results show that Vertisols can store significantly more SOC, and in greater depth than Mollisols under similar climatic conditions.