By: Brad Carlson, Extension educator Urea is now the most used nitrogen (N) fertilizer source in Minnesota. The switch away from anhydrous ammonia (NH3) has occurred for many reasons. Some of these include safety of the product, needing specialized equipment for storing, handling and applying, and a narrow range of soil conditions when anhydrous ammonia can be applied. Despite these issues, there are reasons to still consider anhydrous the best source of N in many situations. The science The N content of anhydrous ammonia is 82%, making it the most concentrated N fertilizer available, and therefore the most efficient with respect to its weight and the space it takes up. This means that less product needs to be transported and applied to the field to get the desired N rate. This results in savings of both time and money for the farmer. Anhydrous ammonia is the feedstock from which all other N fertilizers are produced. This means that every other product – such as urea and urea ...