“[Anhydrous ammonia] can be a fickle form of nitrogen ... “Urea is available in granular, prilled or liquid form,” Michaelsen explains. “In its granular form, urea can be surface applied ...

Ammonium nitrate is a 50-50 mixture of ammonium and nitrate nitrogen. Although the modern-day "prilled" ammonium nitrate material is much less hydroscopic (picks up moisture from the air) than that of ...