Southeast Research and Demonstration Farm
In 1999, a 45-acre tile spacing project was installed adjacent to the Southeast Research Farm. This was done through donations by local drainage contractors, tile companies, and with assistance from the staff at the Southeast Research Farm. The goal was to compare recommended tile spacing (75 ft) with closer tile spacings.
Iowa State University
Brenneman, Greg, "Tile Spacing Results" (2010). Iowa State Research Farm Progress Reports. 442.