Submitted to: Society of Environmental Toxicology and Chemistry Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/30/2003
Publication Date: 11/16/2003
Citation: Bouldin, J.L., Farris, J.L., Moore, M.T., Cooper, C.M. 2003. Vegetative and structural characteristics of agricultural drainages in the Mississippi Delta landscape. Abstract Book of the 24th Annual Meeting of the Society Of Environmental Toxicology And Chemistry. p. 250.
Technical Abstract: Agricultural drainage ditches are an important aspect of the Mississippi Alluvial Delta landscape and vary from small edge-of-field waterways to sizeable drainage systems. Attributes of these ditches vary with size, location and maintenance and are important in determining the functionality that aids in mitigation of contaminants from agricultural fields. The goal of this study was to better understand how vegetative characteristics affect water quality in conveyance structures in the context of ditch class and surrounding land use. A total of 36 agricultural ditches in the Mississippi Delta were characterized by spoil size, presence of riparian buffer strips, hydroperiod, water depth, surrounding land use and vegetative cover, concurrent with associated aqueous physicochemical parameters. Vegetation was assessed quantitatively, obtaining stem count in a sub-sample of sites, using random quadrate method. Physical features varied with ditch size and vegetative diversity was higher in larger size structures. Four vegetative types were ubiquitous among site sizes with Polygonum sp. being the dominant bed vegetation. Macrophytes varied from aquatic to upland species, and included cutgrass (Leersia sp.) and upland grasses (Poaceae family) in all drainage size classes. Percent cover of bed and bank varied from 0-100% and 70-100%, respectively, and highest nutrient values were measured in sites with no buffer strips. These conveyance structures and surrounding buffer zones serve to mitigate contaminants often found in runoff that may include excess nutrients, suspended solids and pesticides.