Ammonium nitrate urea solution

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Ammonium nitrate urea solution ( AHL for short ) is a liquid fertilizer that contains nitrogen.

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 or 28% by weight nitrogen.

designation N
[%] 		Density
[kg / m³] 		Viscosity *
[mPa s] 		Vapor pressure *
[mbar] 		Salting out temp.
[° C]
UAN-32 32 1325 4.7 4.1 ~ −2
UAN-30 30th 1302 ~ −10
UAN-28 28 1279 2.9 7.6 ~ −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. This reduces corrosion during storage and transportation and reduces the decomposition of urea and ammonium nitrate. AHL has a higher density (1.28 g / cm³) than water. The etching 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, one 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 liquid-carrying parts must be liquid fertilizer-proof. Its properties change when water is added. AHL can cause plant burns if the dosage is too high or if mixed with water in certain proportions.

Applications

The most common applications are when the first nitrogen application occurs in spring in the cultivation of grain and rape. 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 .

The other fertilization measures in grain can be carried out with special application technology: On the one hand, multi-hole nozzles that emit individual jets and thus reduce the contact surface with the grain. In addition, drag hoses that are intended to deploy AHL close to the ground.

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