Grains and field crops
Ammonium nitrate is a source of nitrogen containing half
its nitrogen in the ammonium form and half in the nitrate form.
Some properties are set out in comparison with urea in the
Ammonium nitrate has an advantage over urea in that it can
be topdressed onto the surface of the soil and left uncovered
without a danger of loss of nitrogen to the atmosphere. When urea
is left uncovered on the surface of the soil losses of nitrogen occur
through volatilisation of ammonia during the hydrolysis of the urea.
Such losses with ammonium nitrate are only likely to occur on highly
calcareous soils. The loss from urea can be largely avoided if the
urea is covered with a layer of soil e.g. by topdressing in front of
the seeding tines or discs. Also there is not likely to be much
loss from the urea topdressed onto the soil surface if the application
is followed closely by heavy rain which will wash the urea into
On the other hand freight will be a little higher for
ammonium nitrate because of its lower nitrogen content than urea.
Number of Pages
Western Australia, Fertiliser, Application rates, Ammonium Nitrate, Urea
Mason, M G. (1969), Ammonium Nitrate Vs Urea. Department of Primary Industries and Regional Development, Western Australia, Perth. Report.
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