Is urea and ammonium nitrate the same

Ammonium nitrate urea solution

Ammonium nitrate urea solution (short: AHL) is a pressure-free, nitrogenous liquid fertilizer.

Composition and properties

AHL (or UAN = Urea Ammonium Nitrate) is a colorless liquid mixture of ammonium nitrate, urea and water. Commercially available grades have 32, 30 and 28% by weight of nitrogen.

description N
[kg / m³]
[mPa s]
Vapor pressure *
Salting out temp.
[° C]
UAN-323213254,74,1~ -2
UAN-30301302~ -10
UAN-282812792,97,6~ -18

* at 15.6 ° C

AHL with 28 percent by weight nitrogen (N) is composed of 7% nitrate nitrogen, 7% ammonium nitrogen and 14% amide nitrogen (from the urea). The pH value for commercial goods is 7 to 7.5, which is adjusted with a slight excess of ammonia during manufacture (reduces corrosion during storage and transport, reduces decomposition of urea and ammonium nitrate). AHL is heavier than water (specific gravity 1.28). The corrosive intensity of the non-volatile AHL, which smells slightly of ammonia, can be compared with brine or brine.

The following reference values ​​are therefore important:

  • 100 kg AHL = 28 kg N
  • 100 l AHL = 36 kg N

To check the nitrogen content, 1 liter of AHL can be weighed (weigh 1.28 kg at 15 ° C). To compensate for lime, 1 kg of pure nitrogen from AHL requires 1 kg of calcium oxide (CaO).

AHL attacks bare iron and non-ferrous metals. All parts in contact with liquids must be liquid fertilizer-proof. Its properties change when water is added. If the dosage is too high, AHL can cause plant burns.


The most common uses are for the first nitrogen application in spring in the cultivation of grain and rapeseed. In the case of cereals, there is the option of combining herbicides with AHL on almost all areas where weed control was not carried out in autumn.

Category: fertilizer