Title: Sediment redistribution in a mixed land use watershed in central Pennsylvania Authors
|Sripada, Ravi -|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: April 27, 2009
Publication Date: November 1, 2009
Citation: Schmidt, J.P., Sripada, R.P., Ritchie, J.C. 2009. Sediment redistribution in a mixed land use watershed in central Pennsylvania [abstract]. ASA-CSSA-SSSA Annual Meeting Abstracts. Paper No. 53913. CDROM Interpretive Summary: An interpretive summary is not required.
Technical Abstract: Radioactive fallout Cesium (137Cs) has been used to determine the rates and pattern of soil erosion at the landscape scale. The objectives of this research were to determine patterns of soil erosion and deposition in a watershed of the Ridge and Valley physiographic region of Pennsylvania, and to determine the relative contributions of stream bank erosion or field (soil surface) erosion at the watershed outlet. The study area is WE-38, a 7.2-sq. km subwatershed of east Mahantango creek, a tributary of the Susquehanna River and Chesapeake Bay. Soil samples were collected along 16 transects from six different land use areas. Four transects were selected each from pasture, continuous row crop, and wood. Two transects were selected each from Christmas tree and row crop / forage. Within each transect samples were collected at six locations along the hillslope (summit to toe slope) to a depth of 20 or 50 cm at increments of 10 cm. Additional sediment samples were collected from the watershed outlet, stream banks, road cuts, gullies, and undisturbed reference areas. The count for 137Cs was determined using Gamma-ray analyses Canberra-2000 Genie-2000 Spectroscopy System. The least disturbed land use in this watershed was wood, with a 137Cs count from 12 to 35 Bq per kg in the surface soil. The 137Cs count from the surface soil of continuous row crop, row crop / forage, and Christmas tree land uses were consistently below 10 Bq per kg, indicating a similar degree of soil erosion among these land uses. Pasture occupied the lowest landscape positions along stream corridors, and the 137Cs count in the surface soils were sometimes greater than 20 Bq per kg and sometimes less than 10 Bq per kg, an indication of variably reworked sediment. Greater 137Cs count lower in the soil profile were indicative of soil accumulation at lower landscape positions.