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Vegetation is often used to control erosion on right-of-way construction sites, but disturbed conditions provide challenges. This research evaluated the impact of common techniques for preparing seedbeds. The study assessed the use of topsoil, and the use of a hydraulic erosion-control product was compared to straw. Experimental seed mixtures were evaluated to understand how native and non-native seeds performed. The intent was to identify critical practices to use in general seeding and mulching specifications. A plot study was conducted comparing vegetation established during one growing season. Treatments included combinations of seed mixture, topsoil treatment, and mulch types. Three seed mixtures were considered: (1) currently used mixture, (2) a warm-season experimental mixture, and (3) a cool-season experimental mixture. Plots with topsoil and no topsoil were compared, and both straw and hydraulic erosion control products were considered. Ground cover, compaction, and biomass were evaluated. Results suggest that alternative seed mixtures that include native and low-threat-level species can provide adequate cover to meet permitting requirements in the first growing season. The warm-season seed mixture provided less cover than the other two mixtures after eight days, but no differences were determined in ground cover among the three seed mixtures at the end of the growing season. Initial germination was improved with hydraulic mulch, but long-term cover was equivalent between hydraulic and straw mulch. Topsoil application would not be recommended if the soil contains undesirable species, and the use of organic amendment products may be more desirable than topsoil alone; however, specifications need to allow the use of these products.

Development of an Erosion Control Seed Mixture that Includes Native Species George A. Hilvers The West Virginia Divisions of Highways (WVDOH) utilizes the establishment of grass cover as a temporary and permanent management practice to mediate the effects of erosion on highway construction sites. Current West Virginia regulations include five seed mixtures for permanent applications that include combinations of nine species. Six of these species are identified as invasive, and all nine species are considered introduced or both native and introduced. This research developed alternative seed mixtures that included low threat or native species. The alternative seed mixtures were then evaluated in a field test. The research also examined seedbed preparation techniques, the performance of soil amendment and media products, and need for a high elevation specific mixture. Four plots were developed to test these variables over a 90 day period. The sites were monitored biweekly for percent cover. Sensors were in place to monitor precipitation, ambient air and soil temperatures, volumetric water content, and electrical conductivity. Four alternative mixtures (mowable areas, warm season, cool season and high elevation) performed as well or better than current WVDOH seed mixtures. Statistical analysis determined a high elevation specific mixture was not required to achieve adequate coverage at high elevations in West Virginia. After ninety days there were no significant differences among seedbed preparation techniques. I would like to take this time to thank the various individuals who aided in the success of this project. A special thanks and gratitude goes to my research advisor Dr. Leslie Hopkinson for her support and guidance in the development and evaluation of the project. I am greatly appreciative for her superlative role as my mentor, committee chairperson, and academic advisor. Concerning the development of the seed mixtures, I would like to thank Mark B. Fiely from Ernst Conservation Seeds, Elizabeth A. Byers from the WVDNR, and Casey Shrader and Sonya Keith from the NRCS in Lexington, KY. Their assistance and vast knowledge allowed for the development of the proposed seed mixtures for the project. I would also like to thank Charlie Riling, Donald Williams, and Michael Pumphrey from the WVDOH for assisting in the experimental site selection and their assistance and evaluation throughout the project duration. Finally, I would like to thank Dr. Avinash Unnikrishnan and Dr. Yoo Jung Yoon for serving as committee members. For product selection, assistance, and application, I would like to thank Profile Products, LLC for donating their time, expertise, and erosion control products to the benefit of the research. Verdyol was also much appreciated for their donation and product assistance for one of their soil amendment products. Also, I would like to thank Arnold's Custom Seeding, LLC for donating their time, knowledge, and equipment for the application of the various erosion control products used in this study. Without ...

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