The Deterioration of Manures. 
17 
are of considerable interest as some of the samples gave abnormal 
amounts of nitrogen as nitrates. The following table gives the results 
obtained from those samples which had been kept. 
Sample No. 
Age 
Percent N 
17 
Fresh 
None 
17 
1% years 
0.465 
1 7 
3 years 
0 - 7 S 2 
15 
Fresh 
None 
16 
Fresh 
Trace 
18 
1 year 
0-371 
21 
1 year 
0.108 
25 
3 years 
0.287 
26 
3 years 
1.610 
.27 
3 years 
0.821 
3 1 
4 years 
00 
00 
►H 
6 
33 
4 years 
2.151 
35 
5-0 years 
0.093 
The method used for these determinations was that of Schlosing 
and Grandeau as modified by Tieman and Schulze. Ten to twenty 
grams of manure were extracted with water and the filtrate and 
washings concentrated to a convenient volume from which point the 
above method, depending upon the reduction of nitric acid to nitrous 
oxid, was used. Precaution was taken in each case to absorb all carbonic 
acid by means of solid caustic soda in contact with the gas. To make 
sure that the gas was really NO, oxygen was admitted to the measuring 
tube a bubble at a time, and it was then found that all the gas oxidized 
readily and dissolved in water. 
Voelecker* found only traces, not enough to determine quantita¬ 
tively, of nitrates in either fresh or rotted manures. Holdefeiss also says 
that no nitrates are found when the manure is kept moist but that nitrates 
can form if the manure is covered with earth or is allowed to dry out. 
Holdefeiss found that as high as 8.5 percent of the nitrogen was pres¬ 
ent in a moist heap covered with earth, and an unmoistened heap 
carried as much as 18 percent of the nitrogen as nitrates. 
The manure piles considered in this bulletin were, of course, not 
covered with earth and were not moistened except by the infrequent 
rains. The fresh manure contained none or doubtful traces of nitrates. 
In manure No. 17 there has been a steady increase in nitrogen as nitrates 
from none in the fresh manure to 8.5 percent of the nitrogen present 
as nitrates in the three-yeai*-old manure. The other samples do not 
follow this increase with age, some being high and some very low in 
nitrates. Nor does the amount of nitrate present seem to be governed 
*As given in Storer’s Agriculture Vol. II. p. 319. 
