Ammonium nitrogen fertilizers include ammonium bicarbonate (NH4HCO3), ammonium sulfate {(NH4)2SO4}, ammonium chloride (NH4Cl), ammonia (NH3.H2O), liquid ammonia (NH3), and the like.

The common characteristics of ammonium nitrogen fertilizer:

1. Ammonium nitrogen fertilizer is easily adsorbed by soil colloids and partially enters the clay mineral crystal layer.

2, ammonium nitrogen easily oxidized into nitrate.

3, ammonia volatilization loss in alkaline environment.

4. High-level ammonium nitrogen is prone to poisoning crops.

5. Absorption of excessive ammonium nitrogen by crops has a certain inhibitory effect on the absorption of calcium, magnesium, and potassium.