Ammonium in Soils

Photometric determination using the indophenol blue method after to extraction with calcium chloride solution

Calcium chloride solution 0.025 mol/l
Dissolve 3.68 g calcium chloride dihydrate for analysis with 1 l of water for analysis.

Sample Preparation

Charcoal activated for soil tests
Folded filter

In a glass bottle mix 50 g of naturally moist sample, free from coarse stones, with 100 ml of the calcium chloride solution 0.025 mol/l. Add a spatula - tipfull of charcoal activated for soil tests and shake the closed bottle in a shaking machine for 1 hour (alternative stir in a beaker). Let the suspension settle and filter it through a folded filter. For determination of the water - content dry a similar sample to constant weight in the drying kiln at 105 °C. A drying of the sample before determination is not advisable because of the fast change in the nitrogen-forms. The analysis should take place very quickly. Storing the sample in plastic bags at room temperature changes the analysis values after a short time already.


Determine with the below mentioned test kits.


Ammonium content in mg/kg NH4 = analysis value in mg/l NH4 x 2


Product 114544 is not compatible with Move 100.