Return on Nitrogen Investment app for iPhone and iPad

This app is designed as a tool in determining economic nitrogen (N) rates. This calculator determines the return on investment (ROI) of N fertilizer for multiple crops under two different scenarios. The first scenario is that yield fertilized for is not realized. For example a producer applies N at a rate to reach 200 bushels of grain per acre. What is the return if the yield level is 150 bushel or 100 bushel. The other scenario is if the producer under fertilizes for the environment. For example the producer only applies enough N to reach 100 bushel per acre however the environmental potential was 150 bu.