Growers using anhydrous ammonia should wait until soil temperatures move below 50 degrees. Even at these low temperatures, ammonia will slowly nitrify which allows nitrogen to be lost. Better yet, spring applications of ammonia further reduce the opportunity for losses.
The issue with early application of anhydrous ammonia is that the nitrogen may move resulting in losses from either leaching or denitrification. Denitrification is a process in which soil microbes