Ammonia: Ammonia is used in limited quantities as a direct application fertilizer, and is primarily used as a building block for other nitrogen products, including intermediate products for industrial applications and finished fertilizer products. Ammonia, consisting of 82% nitrogen, is stored either as a refrigerated liquid at minus 27 degrees, or under pressure if not refrigerated. Although it is gaseous at ambient temperatures, it is injected into the soil as a liquid where it is rapidly absorbed. The direct application of ammonia requires farmers to make a considerable investment in pressurized storage tanks and injection machinery, and can only take place under a narrow range of ambient conditions.
Ammonium Nitrate: Ammonium nitrate is another dry, granular form of nitrogen based fertilizer. It is produced by converting ammonia to nitric acid in the presence of a platinum catalyst reaction, then further reacting the nitric acid with additional volumes of ammonia to form ammonium nitrate liquid, which is granulated as a solid containing 35% nitrogen.
Urea: Urea is formed by reacting ammonia with carbon dioxide (CO2) at high pressure. From the warm urea liquid produced in the first, wet stage of the process, the finished product is mostly produced as a granular solid containing 46% nitrogen and suitable for use in bulk fertilizer blends containing the other two principal fertilizer nutrients, phosphate and potash.
Urea Ammonia Nitrate Solution (UAN): Urea solution can be combined with ammonium nitrate solution to make liquid nitrogen fertilizer (urea ammonium nitrate or UAN). These solutions contain 32% nitrogen and are easy to store, transport and provide the farmer with the most flexibility in tailoring fertilizer, pesticide and fungicide applications.
Click on any of the images above to read about the four principal nitrogen-based fertilizer products: ammonia, ammonia nitrate, urea, and urea ammonium nitrate.