The Deterioration of Manures. 
21 
fects of the larger content of moisture which prevented a part of the 
ss of ammonia, or, which amounts to the same thing so far as the 
due of the manure is concerned, retarded ammonification, and allow- 
! more time for the formation of ammonium salts. The moisture 
so helps check excessive heating, which dissipates much of the nitro- 
;n as ammonia in a semi-arid climate. 
Another prominent case in point is No. 35, with 64 percent 
oisture which, though five or six years old, has retained 0.759 per- 
nt free ammonia. 
It will be noticed that the free ammonia amounts to about half 
e total nitrogen in the fresh manures and that there was a large loss 
1 air-drying these samples. As we pass down the table to the older 
anures, this loss on drying becomes less until from No. 30 on there 
scarcely any free ammonia, and practically no loss on air-drying, ex- 
pt in the case of No. 35 which was moist enough to retain 0.759 per- 
nt of free ammonia. This seems to indicate that at the end of about 
ree years ammonification has entirely ceased, and the ammonium salts 
rmed have either been lost or changed into nitrites and nitrates. It is 
obable that ammonification practically ceases long before this, es- 
cially 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 
rral, contained 1.48 percent of free ammonia, which makes 130 
unds in the ten tons of manure. At the end of 15 months there were 
t 32.2 pounds of ammonia. If no loss had occurred during this 
ie our total nitrogen ought to be about the same in the sample 
ten placed in the crib and again a year and a quarter afterwards, but 
h that the total nitrogen has shrunken from 237.9 pounds in the 
1 tons 40 122.4 pounds when sampled again, a loss of 115.5 pounds, 
e know that some leaching occurred during this time but it surely 
ild not have been of much consequence when no potash was lost. 
ie loss of nitrogen must, therefore, occur almost wholly through a 
s of ammonia. 
Furthermore, from a series of determinations of nitrates, as given 
ewhere in this bulletin, there was present but 0.121 percent of the 
nure as nitrates at the end of 15 months. There might have been 
ne nitrates present, but certainly not much of the ammonia had 
pn converted into nitrates. 
In all probability the greater portion of the work of ammonifica- 
n had taken place and the 32 pounds of free ammonia obtained at 
r ' en d of 15 months were simply ammonium salts awaiting nitri- 
ation. At the end of the second year there were but 7..1 pounds 
