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The nitrogen in Scorecard's calculations is the nitrogen present in the waste at the time it
is voided from the animal (i.e., leaves the animal's body). A considerable amount of
nitrogen is volatilized, or lost to the air, as ammonia between the time it is voided and the
time the waste is applied to a field. Ammonia volatilization occurs while the waste is still
in the hoghouse, and the fans used for ventilation pump the nitrogen-laden air to the
external atmosphere. Further volatilization occurs from the lagoon surface once the waste
is transported to the lagoon. Finally, the process of spraying the lagoon slurry onto a
field also causes loss of ammonia to the atmosphere. The amount of nitrogen being
applied according to a certified waste management plan does not include the significant
amount of nitrogen that is lost to the air during the processes described above. The
volatilized ammonia ends up being deposited in precipitation or in dust particles some
distance away.
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