Wednesday, November 15, 2006
302-2
Genesis and Spatial Distribution of Upland Soils and Paleosols in East Central Kansas.
DeAnn Presley1, M.D. Ransom1, and William Wehmueller2. (1) Kansas State Univ, 2728 Throckmorton Plant Sciences Center, Manhattan, KS 66506, (2) USDA-NRCS, 760 S Broadway, Salina, KS 67401
East central Kansas is largely comprised of alternating, level beds of Permian and Pennsylvanian shale and limestone. Upland soils in this region have a complex genesis, often contain one or more paleosols, and form in multiple parent materials including loess, colluvium, residuum, and old alluvium. In this study the objectives are to examine the morphology, genesis, and spatial distribution of the soils of interest and how this varies within soil profiles, between soil series, across landscapes, and throughout the current mapping extent. The series of interest include the Irwin series which is mapped on interfluves and benches as well as paleoterraces and classify as fine, mixed, superactive, mesic Pachic Argiustolls. The Ladysmith series is also mapped on both uplands and paleoterraces, and these soils classify as fine, smectitic, mesic Udertic Argiustolls. Methods used in this study included terrain analysis, field descriptions and sampling, micromophological investigations, and laboratory characterization, including mineralogy. Terrain analysis results illustrated that in given drainage areas the soil series were mapped on a wide range of slope positions. Field observations supported this finding and no relationships between mollic epipedon thickness, solum thickness, paleosol thickness or depth to the paleosol with respect to landform were evident. Micromorphological investigations revealed increasing soil development with depth, i.e., the presence of two paleosols beneath the modern soil. Particle size analysis generally supported field observations for changes in parent material between the lower and upper paleosol, but not between the upper paleosol and the modern soil. This lithologic discontinuity was best supported by micromorphological observations and mineralogy. The mineralogy of the modern soil is dominated by smectite, while the paleosols have a more mixed mineralogy containing approximately equal amounts of clay mica, kaolinite, and smectite. Results from this study will be provided to the USDA-NRCS for use in future soil survey updates.
Handout (.pdf format, 58.0 kb)