Northwest and Allee Research and Demonstration Farm
The Northwest Research Farm (NWRF) in Sutherland was selected as a site to research the effect of eggshell application and the effect of ag lime on soil pH and crop yields (Table 1). The research area was identified in April 2002 at the recently acquired 120-acre tract of land adjacent to the NWRF location. In April 2002, the research area had an initial pH of 5.4 and phosphorus and potassium levels were 24–31 ppm and 151–215 ppm, respectively.
Iowa State University
Kassel, Paul C., "Effects of Eggshell and Ag Lime Applications on Soil pH and Crop Yields" (2005). Iowa State Research Farm Progress Reports. 1275.