Surface runoff in Beasley Lake Watershed: Effect of land management practices in a Lower Mississippi River Basin watershed

Authors: Locke, Martin; Lizotte, Richard; Witthaus, Lindsey; Bingner, Ronald - Ron; Moore, Matthew

Submitted to: Journal of Soil and Water Conservation Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/2/2019
Publication Date: 5/12/2020
Citation: Locke, M.A., Lizotte Jr, R.E., Yasarer, L.M., Bingner, R.L., Moore, M.T. 2020. Surface runoff in Beasley Lake Watershed: Effect of land management practices in a Lower Mississippi River Basin watershed. Journal of Soil and Water Conservation Society. 75(3):278-290. https://doi.org/10.2489/jswc.75.3.278.
DOI: https://doi.org/10.2489/jswc.75.3.278

Interpretive Summary: Assessment of agricultural best management practices in the landscape is needed to better understand their potential for mitigating sediment and nutrient losses in runoff. Runoff and sediment and nutrient losses from sub-drainage areas were monitored from 2011 to 2017 in a Mississippi Delta oxbow lake watershed that was part of the USDA Conservation Effects Assessment Program (CEAP). Landscape practices that were assessed included areas under row crops with and without edge-of-field buffers and under the Conservation Reserve Program (CRP). The study demonstrated that use of edge-of-field vegetated buffers and conservation reserve can be integral components in an agricultural landscape to reduce topsoil loss and transport of nutrients downstream concomitantly mitigating water quality impacts on rivers and lakes. Results from this study should be of interest to regulatory and other agencies and farming stakeholders by providing additional information to improve and sustain water quality and overall environmental quality using combined conservation practices.

Technical Abstract: Several United States Department of Agriculture (USDA) conservation programs are promoting conversion of cropland to non-agricultural use, e.g., buffer establishment for wildlife habitat and Conservation Reserve Program (CRP). These areas set aside for non-agricultural use may serve as barriers to mitigate runoff within a watershed where agricultural activities are conducted. CRP and wildlife buffer areas were established in Beasley Lake Watershed, Sunflower County, Mississippi, USA, in 2003 and 2006, respectively. Catchment runoff water quality from CRP and from wildlife buffers adjacent to row crop fields (CropBuff) was assessed from 2011 to 2017 by comparing to runoff from row crop catchments with no buffers (Crop). Average runoff from Crop sites was greater than that from CRP catchments (339 m3 ha-1 vs. 294 m3 ha-1). Suspended solid loads in runoff averaged 2938 kg ha-1 for Crop compared to 270 kg ha-1 in CropBuff areas. Similar trends were observed for average total Kjeldahl nitrogen (TKN) and total phosphorus (TP) loss in runoff: TKN 1.29, 2.03 and 0.26 kg ha-1; and TP 0.37, 0.55 and 0.08 kg ha-1 for Crop, CropBuff, and CRP, respectively. For both CRP and CropBuff, the proportion of soluble / fine particle (<0.45 'm) TKN and TP lost in runoff was greater than that of particulate-bound TKN and TP from Crop. Overall, efficacy in mitigating runoff losses were generally in the order of CRP, CropBuff, and Crop. While implementing combinations of conservation practices improved the quality of Beasley Lake and reduced losses of soil and nutrient resources, significant within-lake processes may limit the effectiveness of land management in improving downstream water quality.