WHAT IS POTENTIAL AMMONIA?
“You say,” said the Deacon, “that dry muck contains twice as much
‘_potential ammonia_’ as manure?”
“Yes,” said the Doctor, “it contains three or four times as much as the
half-rotted straw and stalks you call manure.”
“But what do you mean,” asked the Deacon, “by ‘_potential_ ammonia?’”
“It is a term,” said the Doctor, “we used to hear much more frequently
than we do now. Ammonia is composed of 14 lbs. of nitrogen and 3 lbs. of
hydrogen; and if, on analysis, a guano or other manure was found to
contain, in whatever form, 7 per cent of nitrogen, the chemist reported
that he found in it 8½ per cent of ‘potential’ ammonia. Dried blood
contains no ammonia, but if it contained 14 per cent of nitrogen, the
chemist would be justified in saying it contained 17 per cent of
potential ammonia, from the fact that the dried blood, by fermentation,
is capable of yielding this amount of ammonia. We say a ton of common
horse-manure contains 10 or 12 lbs. of potential ammonia. If perfectly
fresh, it may not contain a particle of ammonia; but it contains
nitrogen enough to produce, by fermentation, 10 or 12 lbs. of ammonia.
And when it is said that dry swamp-muck contains, on the average, 2.07
per cent of potential ammonia, it simply means that it contains nitrogen
enough to produce this amount of ammonia. In point of fact, I suppose
muck, when dug fresh from the swamp, contains no ammonia. Ammonia is
quite soluble in water, and if there was any ammonia in the swamp-muck,
it would soon be washed out. The nitrogen, or ‘potential ammonia,’ in
the muck exists in an inert, insoluble form, and before the muck will
yield up this nitrogen to plants, it is necessary, in some way, to
ferment or decompose it. But this is a point we will discuss at a future
meeting.”