Influence of Alluvial Sedimentation Rate on Floodplain Soil Developement and Vegetation

Abstract

The purpose of this study was to evaluate soil forming and sedimentary processes responsible for the formation of two key paleosols in the Southern Plains (the Caddo and Copan Soil). Vertical trends in organic carbon content and clay-free particle size distribution were used to delineate sedimentary events and evaluate subsequent soil forming processes. Systematic changes in clay-free particle size and organic carbon content distribution with depth revealed sedimentary sequences throughout profiles, as well as, cumulic and pachic soil formation within thick mollic A horizons of buried soils. The purpose of this study was to evaluate established herbaceous plant community response to burial by sedimentation and to serve as a pilot study for future studies of this kind. Sediment burial depths of 8, 16 and 24 cm were applied to established herbaceous plant plots in the spring. Percent plant coverage by species was then evaluated during the following growing season. Sediment burial depths of 8, 16 and 24 cm had no effect on percent coverage of pre-existing forb species. While, burial depths of 8, 16 and 24 cm killed almost all pre-existing grass species.