26 
COLORADO EXPERIMENT STATION 
In No. 88, we have nitrification going on in the control but rather 
feebly. There was no increase in the nitric nitrogen with the ad¬ 
ditional supply of ammonia nitrogen. Knowing the condition and his¬ 
tory of this soil, I am inclined to explain this by a loss of vitality and 
virulence on the part of the organisms rather than by their inability 
to attack ammonium sulphate. The water soluble salts in this soil were 
very high and the nitrifying bacteria were, in all probability, intoxi¬ 
cated, so to speak, by the saline solution. 
Series II. Ammonium Chlorid 
The results of the. next series are given in Table No. 2. Here the 
ammonia nitrogen was furnished in the form of ammonium chlorid. A 
TABLE NO. 2.—Nitrification of Ammonium Chlorid by Colorado Soils. Nitrogen in Parts Per Million of 
Air-dried Soil as Nitrites and Nitrates from 100 m.g. Nitrogen as NH^Cl 
Duration of Experiment: 6 Weeks at 28 Degrees C. 
Nitrogen as nitrites Nitrogen as nitrates Chlorin 
v» , f , , in parts per million in parts per million in 
Number of Sample and a __ _ a _n n m 
t-v ... Check 
Check NH Cl 
Check 
Check 
NH Cl 
Total 
-\ K 
Net 
description 
83 Apple orchard, heavy 
clay, niter . 
at 
begin. 
.02 
at 
end 
.36 
4 
added 
.06 
at 
begin. 
6. 
at 
end 
100. 
4 
added 
120. 
gain 
114. 
gain 
20. 
58. 
84 Apple orchard, heavy 
clay, niter . 
.14 
.52 
.10 
Trace 
68. 
320. 
320. 
252. 
138. 
85 Apple orchard, clay 
loam, niter . 
.012 
.10 
.20 
6. 
60. 
12. 
6. 
—48. 
1,000. 
86 Oat field, sandy loam, 
niter . 
.00 
. 14 
.04 
130. 
240. 
160. 
30. 
—80. 
6,400. 
87 Apple orchard, clay 
loam, niter . 
.10 
.12 
.072 
6. 
40. 
32. 
26. 
—8. 
202. 
88 Apple orchard, clay 
loam, niter . 
.40 
. 14 
.02 
70. 
100. 
100. 
30. 
0. 
8,300. 
89 Apple orchard, sandy 
loam, niter . 
.40 
.60 
.08 
180. 
260. 
200. 
20. 
—60. 
1,600. 
90 Apple orchard, sandy 
loam, niter . 
.32 
.40 
.10 
13. 
60. 
120. 
107. 
60. 
140. 
91 Apple orchard, heavy 
clay, normal . 
.32 
.14 
.112 
Trace 
40. 
72. 
72. 
32. 
8 o. 
92 Oat field, sandy loam 
niter . 1 
.40 
.20 
.18 
320. 
320. 
280. 
—40. 
—40. 
7,800. 
93 Peach orchard, heavy 
clav, normal . 
94 Apple orchard, clay 
niter . 
.60 
.60 
.112 
4. 
48. 
120. 
116. 
72. 
120. 
. 14 
1.20 
.10 
34. 
92. 
240. 
206. 
148. 
420. 
95 Apple orchard, brown 
surface . 
.26 
.14 
.06 
600. 
640. 
680. 
80. 
40. 
150. 
96 Peach orchard, sandy 
loam, normal . 
.24 
1.00 
. 12 
20. 
60. 
96. 
76. 
36. 
170. 
97 Apple orchard, clay, 
niter . 
.36 
1.40 
.26 
20. 
132. 
560. 
540. 
428. 
65. 
glance at the net 
gain 
column 
of this table 
brings out the strikin 
g fact 
that ammonium chlorid does not begin to be as fertile a source of nitric 
nitrogen as the sulphate. Whether the additional chlorid has exercised 
an inhabiting action or whether this form, of the salt is more resistant 
to the attacks of the nitrifying organisms is difficult to say. Nine of 
the fifteen samples gave a positive gain in nitric nitrogen with the 
chlorid; one showed no increase and five failed to produce as much as 
the controls. None yielded as much as the respective soils in the sul¬ 
phate series, and all that fell behind here were also below in the pre¬ 
ceding set. All of the negative results point strongly to the inhibi- 
