Location: Water Quality and Ecology ResearchTitle: Effectiveness of integrated best management practices on mitigation of atrazine and metolachlor in an agricultural lake watershed Author
Submitted to: Bulletin of Environmental Contamination and Toxicology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/2016
Publication Date: 3/14/2017
Publication URL: http://handle.nal.usda.gov/10113/5661751
Citation: Lizotte Jr, R.E., Locke, M.A., Bingner, R.L., Steinriede Jr, R.W., Smith, S. 2017. Effectiveness of integrated best management practices on mitigation of atrazine and metolachlor in an agricultural lake watershed. Bulletin of Environmental Contamination and Toxicology. 98(4):447-453. Interpretive Summary: We assessed the influence of land-use and integrated best management practices on spring atrazine and metolachlor herbicide levels throughout Beasley Lake watershed, a Conservation Evaluation Assessment Program watershed in western Mississippi from 1998 to 2013. We observed how changes in land-use and installment of a variety of BMPs changed watershed herbicide use and lake water quality. Over 16 years, atrazine applications changed with land-use cropping patterns and BMPs, while metolachlor applications generally increased over time. Herbicide concentrations in lake water indicated atrazine was influenced by BMPs, rainfall, and cropping patterns while metolachlor was influenced by on-field applications and BMPs. These results are of interest to regulatory and other agencies and farming stakeholders by providing additional information to improve and sustain lake and flood plain water quality and overall environmental quality using conservation practices.
Technical Abstract: The study examined the influence of land-use (cropping patterns) and integrated agricultural best management practices (BMPs) on spring herbicide levels in Beasley Lake water within an agricultural watershed. Atrazine and metolachlor were applied for weed control during spring of 1998-2002, 2005, and 2007-2013. Watershed-wide mass of applied herbicides ranged from 12.7-209.2 g atrazine and 10.9-302.2 g metolachlor with greatest application during 1998, 2009-2010 (atrazine) and 2007-2013 (metolachlor). Spring herbicide concentrations in Beasley Lake water ranged from below detection (< 0.125 µg atrazine/L; <0.0125 µg metolachlor/L) to 3.54 µg atrazine/L and 3.01 µg metolachlor/L. Multiple linear regression analyses with cropping patterns, BMPs, rainfall and time as independent variables, showed atrazine applications were associated with increases in cotton acreage and quail buffer, while metolachlor applications increased over time. Multiple linear regressions showed lake atrazine concentrations were associated with conservation tillage, rainfall, and corn, while lake metolachlor concentrations were associated with the cumulative metolachlor application and sediment retention pond installation.