LaMotte STH Series - Manual (Page 21)

Ammonia Nitrogen
A fertile soil may be expected to give a low ammonia nitrogen test
reading, unless there has been a recent application of nitrogenous
fertilizer in forms other than the nitrate. The rapid disappearance
of ammonia after fertilizer application indicates the desired
transformation of the ammonia to the more available nitrate
compounds. In forest soils ammonia is the most abundant
available form of nitrogen. If there is a satisfactory rate of nitrogen
transformation, the humus layers of a forest soil will produce very
high concentrations of ammonia nitrogen.
Procedure:
1. Use a transfer pipet (0364) to transfer four drops of the
general soil extract to one of the larger depressions on a spot
plate (0159).
2. Add one drop of *Ammonia Nitrogen Test Solution
(5103PS). Stir with a clean stirring rod (0519). Allow to
stand for one minute.
3. Compare the resulting color against the Ammonia Nitrogen
Color Chart (1302). The test result is expressed in relative
values of ammonia nitrogen from very low to very high. For
approximate corresponding values in parts per million or
pounds per acre, see page 22.
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