Remediating Soil for Successful Vegetation Establishment along Nebraska Highways

Successful vegetation establishment on roadsides is imperative to the Nebraska Department of Roads (NDOR). Roadside vegetation provides several vital ecosystem functions that benefits people and the environment. First, well-established vegetation on highway roadsides can prevent erosion and stabilize slopes, directly improving pavement life and serviceability (Cedergren 1974). Second, vegetation on highway shoulders provides hazard-free zones for errant vehicles and reduces blowing and drifting snow onto highway. Third, attaining adequate vegetation cover along roadways helps NDOR comply with the Environmental Protection Agency's (EPA’s) stormwater regulations because proper roadside vegetation could filter and retain pollutants; increase water infiltration, and reduce runoff, thereby improving downstream water quality. (Kaighn and Yu 1996). Finally, roadside vegetation provides habitat and corridors to wildlife and scenic beauty to roads users (Akbar et al. 2003). Roadside soils are highly disturbed systems with altered soil horizons and graded slopes to rapidly remove water runoff from the sites rather than filter into the soil profile, where it can be available for plant use. Creating a favorable growing environment in roadside soils is thus vital not only to manage water quality but also other ecosystem services. Some seeded perennial grasses may not establish or persist, leading to bare soil, which can result in soil erosion. The non-vegetated strip that sometimes develops along the edge of pavement is a problem in every NDOR District. The “bald spots” increases the need for NDOR staff to remediate the shoulder (when drop-offs develop) and can delay the closure of stormwater permits. Improved management strategies are needed to establish vegetation along roadsides. The goal of the second phase of this project is to evaluate remediation practices of roadside shoulders for plant establishment under field conditions.