Project Results and Recommendations

A 1997 review of compost use by state departments of transportation (DOT's) in the U.S. (D. Mitchell, Compost Utilization by Departments of Transportation in the United States. Florida Department of Transportation. 1997) reported that at least 19 state DOT’s had adopted specifications for compost use.  Thirty-four states reported trying compost as a soil amendment to improve the growth of vegetation, as a mulch to reduce soil erosion, and for occasional bio-remediation of contaminated soils.

Despite relatively widespread interest in using compost on road construction projects, only a handful of studies have been conducted to reliably quantify the impacts of compost applications on construction site vegetation, storm water runoff, or erosion.

To help answer questions about the potential value of using composted organics on road construction projects in Iowa, the Iowa Department of Natural Resources and the Iowa Department of Transportation commissioned a 3-year study by Iowa State University researchers. Key findings of this project address five main areas:
 

Recent  literature suggests that many states have experimented informally with use of  compost on construction projects.


Few published studies, however, have measured the effects of compost applications  in the field to determine their impact on quantity and quality of storm water runoff, soil erosion, or production of vegetation.