Equivalent acidity of anhydrous ammonia is

Equivalent acidity is defined as the acidity developed by a fertilizer when applied to soils, measured in terms of calcium carbonate required for its neutralization.
It can be calculated as the calcium carbonate required to neutralize the acid residues caused by acidic fertilizers in the soil.
The equivalent acidity of anhydrous ammonia is 148. It is the highest among all the fertilizers.