The corn yield potential is the expected corn yield (in bushels/acre) 3 to 4 years out of 5 under good management. It depends on a couple factors, below.
Through years of research across New York State, corn yield potentials have been determined for every soil in the state. The corn yield potentials are housed in the Cornell database. Higher yield potentials can be used to calculate corn N requirements if 3 years worth of records of higher yields are present. To get the gross N requirement, the yield potential is multiplied by 1.2, because that's the average N content of corn at optimum yield.
The table, below, contains examples of yield potentials for a range of soils in the Cornell database. Move your mouse over each of the soil names for a description of each soil.
To read more on this subject: Nitrogen Guidelines for Field Crops in New York (section 4.1)