Fertilizer Acid Reaction

Make sure you are not using acid-forming fertilizers in high amounts on acid soils. Avoid any nutrient that is in sufficient quantity. Ammonium fertilizers in addition to having an acid reaction in soils they also are in very acidic soils hard to transfer to nitrates. At pH of 5.5 or below ammonium conversion to nitrite and nitrate is virtually zero.

Fertilizer acid reaction in kg of lime needed to neutralize 100 kg N supplied
Fertilizer	Equivalent kg of lime
Ammonium sulfate	535
Ammonium phosphate	500
Urea	180
Ammonium nitrate	180
Calcium nitrate	-135
Sodium nitrate	-180
Potassium nitrate	-430