Figure 2. Continuous corn nitrogen yield response across 10 years (2008?18), Elora Research Station, University of Guelph, Dr. B. Deen

In Figure 2, the MERN is starred on each year's yield curve. This shows that in continuous corn, the MERN ranged from 140 to 260 kg/ha depending on the year (same soil, same management, and same hybrid). Further analysis of the data showed that in most years applying up to 30 kg/ha more than the MERN or 30 kg N/ha less than the MERN is within about $10.00 of the maximum net returns per acre from nitrogen. Figure 3 shows the relative net returns per acre in green on the corn grain yield curve for each year.