The price of fertilizer nitrogen (N) has increased substantially over the past three months and ranges from $0.37 to 0.60/lb N with anhydrous ammonia at the lower end of the range and poly coated urea (ESN®) at the upper end of the range. Many dealerships are expecting the price of N fertilizer to increase as we move towards planting. With the increasing N prices, questions are being asked regarding how much N should be applied to maximize economic return in corn production. As of mid-December 2007, the price of corn was between $3.80 to $4.25/bu depending on contract, location, etc. Thus, the N:corn price ratio varies from 0.09 to 0.16. These price ratios do not differ substantially from the price ratios that were prevalent in winter 2005/2006.

The maximum return to N (MRTN) tool that was released in 2006 can be used to determine an appropriate N rate for corn with fluctuating N and corn prices. Current N fertilizer and grain prices suggest lower N fertilizer rates should be applied to maximize economic return. The object of this project was to evaluate how the MRTN N rate guidelines performed in 2007.