A. Ammonium nitrogen fertilizer
Ammonium nitrogen fertilizers include ammonium bicarbonate (NH4HCO3), ammonium sulfate {(NH4)2SO4}, ammonium chloride (NH4Cl), ammonia water (NH3·H2O), liquid ammonia (NH3), etc.
Common characteristics of ammonium nitrogen fertilizer:
1. Ammonium nitrogen fertilizer is easily absorbed by soil colloid, and part of it enters the clay mineral crystal layer.
2. Ammonium nitrogen is easily oxidized to nitrate.
3. Ammonia is easy to volatilize and lose in alkaline environment.
4. High concentrations of ammonium nitrogen are 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.
B. Nitrate nitrogen fertilizer
Nitrate nitrogen fertilizers include sodium nitrate (NaNO3), calcium nitrate {Ca(NO3)2}, ammonium nitrate (NH4NO3) and so on.
Common characteristics of nitrate nitrogen:
1. It is easily soluble in water and moves quickly in the soil.
2. NO3-absorption is the main absorption, and crops can easily absorb nitrate.
3. Nitrate fertilizers have no inhibitory effect on the absorption of calcium, magnesium, potassium and other nutrients by crops.
4. Nitrate is a negatively charged anion and cannot be adsorbed by soil colloids.
5. Nitrate is easily reduced to gaseous state (NO, N2O, N2) through denitrification, and escapes from the soil.
C. Ammonium nitrate nitrogen fertilizer
Ammonium nitrate nitrogen fertilizers include ammonium nitrate, calcium ammonium nitrate, and ammonium sulfur nitrate.
D. Amide nitrogen fertilizer
Amide nitrogen fertilizer - urea {CO(NH2)2}, containing N46.7%, is the fertilizer with the highest nitrogen content in solid nitrogen.
