An overview of research into conservation practice effects on soil and water resources in the Upper Washita Basin, Oklahoma, United States

Authors: Moriasi, Daniel; Starks, Patrick; Steiner, Jean; Zhang, Xunchang; Garbrecht, Jurgen; GLASGOW, STEVE - Natural Resources Conservation Service (NRCS, USDA)

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2020
Publication Date: 5/12/2020
Citation: Moriasi, D.N., Starks, P.J., Steiner, J.L., Zhang, X.J., Garbrecht, J.D., Glasgow, S. 2020. An overview of research into conservation practice effects on soil and water resources in the Upper Washita Basin, Oklahoma, United States. Journal of Soil and Water Conservation. 75(3):330-339. https://doi.org/10.2489/jswc.75.3.330.
DOI: https://doi.org/10.2489/jswc.75.3.330

Interpretive Summary: The Conservation Effects Assessment Project (CEAP) was established in 2003 by the USDA Natural Resources Conservation Service in partnership with USDA Agricultural Research Service and many other partners to quantify the environmental effects (at the watershed scale) of conservation practices (CPs) and programs and to develop the science base for managing the agricultural landscape for environmental quality. The Fort Cobb Reservoir Experimental (FCREW) and Little Washita River Experimental watersheds, located within the Upper Washita Basin (UWB) in Oklahoma, are part of the ARS Benchmark CEAP-Watershed Assessment Studies sites. In this study, we present the CPs that have worked based on the findings of the research that has been carried out in these CEAP and other watersheds within the UWB in the last 15 years. The main factors that affect water resources and soil erosion in the UWB are climate, land use, unstable stream channels, and red cedar encroachment. The common CPs that have been implemented over the years to protect soil and water resources are no-till, riparian buffers, and red cedar removal. Overall, results indicate that the effects of CPs on soil and water resources were observed at various spatial scales. For example, multiple CPs in the FCREW over many years protected the soil and reduced suspended sediment yield to water bodies by 86% leading to longer lifespans of most surveyed flood control reservoirs by 1 to 68 years more than the design period of 50 years. Conservation practices that have shown measured or simulated effects on soil and water resources include; grassland conservation from red cedar encroachment, combined streambank stabilization practices, riparian and filter strip buffer practices, and conversion of cropped area into Bermuda grass.

Technical Abstract: The Fort Cobb Reservoir Experimental (FCREW) and Little Washita River Experimental watersheds, located within the Upper Washita Basin (UWB) in Oklahoma, are part of the ARS Benchmark Conservation Effects Assessment Project (CEAP)-Watershed Assessment Studies locations. The CEAP was created in 2003 by the USDA Natural Resources Conservation Service in partnership with USDA Agricultural Research Service and many other partners to quantify the environmental effects of conservation practices (CPs) and programs and to develop the science base for managing the agricultural landscape for environmental quality. The ultimate goal of this work was to present CPs that have worked and the scale at which they have worked, based on the findings of the research studies that have been carried out in these CEAP and other watersheds within the UWB in the last 15 years. Results indicate that the effects of CPs on soil and water resources were observed at various spatial scales. At the large watershed scale, multiple CPs over many years had impacts on soil erosion and sediment yield reductions. With the exception of the impact of red cedar removal, impacts of specific CPs were observed at smaller-scale watersheds. Practices that showed measured or simulated effects on soil and water resources include, grassland conservation from red cedar encroachment, combined streambank stabilization practices, riparian and filter strip buffer practices, and conversion of cropped area to Bermuda grass.