Title: Identification and Management of Critical Fields for a Claypan Watershed Authors
Submitted to: Soil and Water Conservation Society
Publication Type: Abstract Only
Publication Acceptance Date: January 19, 2010
Publication Date: July 17, 2010
Citation: Baffaut, C., Mudgal, A., Anderson, S.H., Sadler, E.J. 2010. Identification and Management of Critical Fields for a Claypan Watershed [abstract]. Soil and Water Conservation Society, July 18-21, 2010, St. Louis, Missouri. Available: http://www.swcs.org/documents/filelibrary/10ac/2010_Oral_Presentation_Abstracts_566DF5164F928.pdf. Technical Abstract: Identifying fields that need conservation to minimize impacts on stream water quality is critical to ensure effectiveness of conservation programs at the watershed scale. This study was located in the 72 km2 Goodwater Creek Watershed, in northeast Missouri. Most soils in this watershed are characterized by a clay layer of extremely low permeability, which can be visible at the surface in eroded sideslope areas or up to one meter deep in footslope areas. Field scale data and simulation results showed that a field’s critical areas can be identified based on surface layer hydraulic conductivity, slope, and depth to claypan. Our objective was to extend these results to the watershed scale. Using criteria developed with field data, critical fields of the watershed were identified. The SWAT model was utilized to simulate runoff, crop yields, and pollutants yields from these areas and compare them to outputs from non-critical areas. Subsequently, alternative management including grasses, specific crop rotations and appropriate tillage practices were simulated on these critical fields to reduce pollutant loadings to the stream. Results include the fraction of cropland in the watershed classified as critical as well as a comparison of runoff and pollutant loadings generated from these fields and other non-critical fields. The effect that implementation of practices may have on stream loadings will be presented. The identification and specific management of these critical areas is important for producers and regulators as it allows better use of cost-share dollars and greater flexibility for producers on the rest of their land.