Date of this Version
Mills,S., Mamo, M., Scacht, W., and Blanco, H. (2019). "Remediating Soil For Successful Vegetation Establishment Along Nebraska Highways". NDOT Research Report SPR-1(18) M079.
Vegetation along roadsides is important to prevent soil erosion, provide habitat, and filter water running off the road. Vegetation close to the pavement along highways in Nebraska does not readily establish and persist. It is thought that the sodium and bulk density are the driving factors behind the lack of vegetation. After a construction project the shoulder is seeded into the compacted soil, and during winter salts can accumulate in the soil because of deicing agents being used. The purpose of our study was to determine if the sodium and bulk density are the driving factors of the vegetation cover. We also looked at how shoulder type and time since seeding affected the soil and vegetation cover. The study was conducted by collecting soil samples and identifying vegetation cover from 53 sites in three different regions, the Panhandle, Southcentral and Southeast regions, in Nebraska, USA. The soil was analyzed for pH, electrical conductivity, sodium, chloride and bulk density. At each site vegetation was designated into one of four categories, bare ground (>70%), annual vegetation (>70%), perennial vegetation (>50%), and bare ground-annual vegetation mix (~50-50%). We found that sodium and bulk density had little effect on the establishment and persistence of vegetation. Shoulder type and time since seeding showed limited effect on the soil variables measured. We suggest that post seeding events and disturbances may be contributing to the lack of vegetation along highways.