Nitrogen Use Efficiency Differences Between Anhydrous Ammonia and Liquid Urea-Ammonium Nitrate.

Traditionally, anhydrous ammonia (AA) has been considered the most efficient N fertilizer, but due to current economic and health concerns, it is becoming a less popular fertilizer, being replaced by the liquid form of urea-ammonium nitrate (UAN). However, UAN does not respond to soil conditions the same way as AA. The objective of this research was to determine if UAN fertilization could be as efficient as anhydrous ammonia at supplementing N to corn under Ohio growing conditions. Multiple site years of N response from both N sources may help improve recommendations using urea-based fertilizers as a supplement to anhydrous ammonia.