Author
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Potter, Thomas |
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Lowrance, Robert |
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Bosch, David - Dave |
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Williams, Randall |
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Submitted to: American Chemical Society Symposium Series
Publication Type: Book / Chapter Publication Acceptance Date: 4/23/2011 Publication Date: 12/21/2011 Citation: Potter, T.L., Lowrance, R.R., Bosch, D.D., Williams, R.G. 2011. Estimating pesticide retention efficacy for edge-of-field buffers using the Riparian Ecosystem Management Model (REMM) in a Southeastern Plains Landscape. In: Goh, K.; Bret, B.; Gan, J; Potter, T.L., editors, Pesticide Mitagation Strategies for Surface Water Quality. American Chemical Society Symposium Series No. 1075, pp 259-271. Interpretive Summary: Agricultural uplands of the southern Atlantic Coastal Plain are intensively cropped. Much of the land in production is vulnerable to erosion and agrichemical runoff; thus there are water quality concerns throughout the region. To reduce impacts farmers are being encouraged to convert fields from conventional to conservation-tillage management and to participate in maintenance and restoration of riparian forests and wetlands as buffers for water resource protection. These forests function as buffers intercepting both surface and subsurface runoff and retaining pesticides and other contaminants. The Riparian Ecosystem Management Model (REMM) which was developed and is supported by our research group was recently modified to simulate pesticide transport and retention processes. We used the model to evaluate how buffers may respond to pesticide runoff from fields. Responses of two commonly used herbicides and whether runoff was from a conventional or conservation-tillage system were assessed. Model inputs were from a 7-yr field scale investigation of the impact of conservation tillage on water quantity and quality during rotational cotton and peanut production. Buffer system responses simulated by REMM were explainable by examining model processes and in agreement with published studies describing pesticide behavior in these systems. These results should provide model users with confidence in using REMM for water quality risk assessments. A useful insight from simulations was that riparian buffers may be less effective in retaining pesticides in runoff and subsurface flow from conservation-tillage systems. This has important implications for landscape scale watershed management. Technical Abstract: Erosion and agrichemical runoff are persistent natural resource concerns. Remedial practices designed to reduce impacts including replacing conventional with conservation-tillage management and maintaining and restoring riparian forests and wetlands as buffers for water resource protection. To effectively assess risk reductions, data and models describing ecosystem-scale responses to these conservation practices are needed. We used the Riparian Ecosystem Management Model (REMM) to evaluate potential buffer systems responses to runoff from farm fields managed under conventinal versus conservation-tillage. Measured data from a seven-year field study conducted in south central Georgia (USA) were used. Generally, buffer system responses simulated by REMM were explainable by examining model processes and in agreement with published studies describing pesticide behavior in vegetated buffer strips. Results should provide model users with confidence in using REMM for pesticide risk assessments. One of the most useful insights from simulations was that riparian buffers are likely less effective in retaining pesticides in runoff and subsurface flow from conservation-tillage systems. This has important implications for landscape scale watershed management |
