The; Deterioration of Manures. 
21 
effects of the larger content of moisture which prevented a part of the 
loss of ammonia, or, which amounts to the same thing so far as the 
value of the manure is concerned, retarded ammonification, and allow¬ 
ed more time for the formation of ammonium salts. The moisture 
also helps check excessive heating, which dissipates much of the nitro¬ 
gen as ammonia in a semi-arid climate. 
Another prominent case in point is No. 35, with 64 percent 
moisture which, though five or six years old, has retained 0.759 P er " 
cent free ammonia. 
It will be noticed that the free ammonia amounts to about half 
the total nitrogen in the fresh manures and that there was a large loss 
on air-drying these samples. As we pass down the table to the older 
manures, this loss on drying becomes less until from No. 30 on there 
is scarcely any free ammonia, and practically no loss on air-drying, ex¬ 
cept in the case of No. 35 which was moist enough to retain 0.759 P er_ 
cent of free ammonia. This seems to indicate that at the end of about 
three years ammonification has entirely ceased, and the ammonium salts 
formed have either been lost or changed into nitrites and nitrates. It is 
probable that ammonification practically ceases long before this, es¬ 
pecially when the manure has been disturbed and aerated. 
The Loss of Ammonia in the Deterioration Experiment. 
The “fresh” manure, or the manure as it was taken out of the 
corral, contained 1.48 percent of free ammonia, which makes 130 
pounds in the ten tons of manure. At the end of 15 months there were 
but 32.2 pounds of ammonia. If no loss had occurred during this 
time our total nitrogen ought to be about the same in the sample 
when placed in the crib and again a year and a quarter afterwards, but 
we'find that the total nitrogen has shrunken from 237.9 pounds in the 
ten tons to 122.4 pounds when sampled again, a loss of 115.5 pounds. 
We know that some leaching occurred during this time but it surely 
could not have been of much consequence when no potash was lost. 
The loss of nitrogen must, therefore, occur almost wholly through a 
loss of ammonia. 
Furthermore, from a series of determinations of nitrates, as given 
elsewhere in this bulletin, there was present but 0.121 percent of the 
manure as nitrates at the end of 15 months. There might have been 
some nitrates present, but certainly not much of the ammonia had 
been converted into nitrates. 
In all probability the greater portion of the work of ammonifica¬ 
tion had taken place and the 32 pounds of free ammonia obtained at 
the end of 15 months were simply ammonium salts awaiting nitri¬ 
fication. At the end of the second year there were but 7.1 pounds 
