Is it true that anhydrous ammonia makes soil hard?
There are some situations where anhydrous ammonia could reduce permeability, but these situations are the exception rather than the norm. Anhydrous ammonia, at the point of injection, can dissolve a portion of soil organic matter, allowing it to move with soil water. On low organic matter soils, where any loss or alteration in organic matter is detrimental, this effect can make the soil seem hard and impermeable. On other soils, this organic matter dissolution and movement actually improves soil structure.
