THE NITRIFYING EFFICIENCY OF CERTAIN COLORADO SOILS 
33 
A peculiar condition existed in No. 53 throughout the investiga¬ 
tion ; the check lost practically all of its nitric nitrogen, but the addition 
of the ammonium sulphate appeared to have retarded denitrification 
so that the soil to which this salt was added showed an excess of 3 p. p. 
m. nitric nitrogen over the control, but at the same time a loss of 2 p. p. 
m. of its initial nitrate nitrogen. Although it contained more nitric 
nitrogen than the check at the end of the experiment, it might be group¬ 
ed more properly with the negatively reacting soils, since the nitric 
nitrogen which was found was in all probability, a part Ad the initial 
content which had not yet been reduced. 
TABLE NO. 5.—Nitrification of Ammonium Sulphate by Foreign Soils. Nitrogen in Parts Per Million 
of Air-dried Soil as Nitrites and Nitrates from 100 m.g. Nitrogen as (NH ) ,SO 
Duration of Experiment: 6 Weeks at 28 Degrees C. 
Nitrogen as nitrites 
Nitrogen as nitrates 
Chlorin 
Number of Sample and 
in parts per million 
A 
in parts 
per million 
_A_ 
in 
p. p. m. 
Description 
Check 
Check 
(nh 4 ) 2 so 4 ' 
Check 
Check 
(NH) 2 so 4 
Total 
Net ' 
at 
at 
added 
at 
at 
added 
gam 
gain 
begin. 
end 
begin. 
end 
52 Corn field, clay loam, 
Ohio . 
.002 
.176 
1.20 
7 . 
60 . 
120 . 
113 . 
60. 
8. 
53 Pine forest, gravelly 
loam, Georgia. 
Trace 
.220 
.44 
5. 
Trace 
3 . 
_2. 
3 . 
78 . 
54 Apple orchard, loam, 
Washington . 
.04 
.340 
.68 
5. 
90 . 
120 . 
115 . 
30 . 
40 . 
55 Apple orchard, heavy 
clay, Virginia. 
Trace 
.160 
.80 
9. 
70 . 
240 . 
231 . 
140 . 
74 . 
56 Cotton field, sandy 
loam, Oklahoma . . 
.18 
.168 
.80 
11 . 
50 . 
70 . 
59 . 
20 . 
8. 
57 Water melons, sandy 
loam, North Carolina 
Trace 
.168 
.80 
7 . 
46 . 
6. 
— 1 . 
— 40 . 
10 . 
58 Cotton field, sandy 
loam, Texas . 
.12 
.160 
.52 
7 . 
50 . 
30 . 
23 . 
— 20 . 
98 . 
59 Cotton field, clay 
Trace 
16 . 
— 30 . 
106 . 
loam, Georgia .... 
.152 
.80 
14 . 
60 . 
30 . 
60 Corn field, clay, 
.16 
70 . 
40 . 
34 . 
— 30 . 
8. 
North Carolina .... 
.112 
1.00 
6. 
61 Tobacco field, sandy 
1 . 
— 16 . 
6. 
loam, N. Carolina. . . 
Trace 
.100 
.52 
3 . 
20 . 
4 . 
62 Vineyard, clay loam, 
136 . 
116 . 
26 . 
California . 
Trace 
Trace 
.48 
4 . 
24 . 
140 . 
63 Alfalfa field, sandy 
136 . 
94 . 
8 . 
loam, Calilornia 
64 Small grain, sandy 
loam, California 
.04 
.100 
1.20 
4 . 
46 . 
140 . 
194 . 
130 . 
8. 
.88 
.320 
1.20 
6. 
70 . 
200 . 
65 Cotton field, sandy 
loam, Arkansas .... 
.60 
.132 
.60 
4 . 
24 . 
480 . 
476 . 
450 . 
62 . 
66 Cane field, clay loam. 
Oklahoma . 
.18 
.136 
.80 
40 . 
126 . 
180 . 
140 . 
54 . 
6 . 
67 Mixed orchard, silt 
loam, California. . . . 
1.80 
1.80 
24.00 
120 . 
140 . 
280 . 
160 . 
140 . 
700 . 
68 Plum orchard, sandy 
8. 
loam, California.... 
.26 
.140 
1.40 
7.4 
40 . 
100 . 
92.6 
60 . 
69 Virgin soil, clay, Cali- 
98 . 
70 . 
8. 
fornia . 
Trace 
.100 
1.00 
2. 
30 . 
100 . 
70 Small grain, black 
adobe, California .... 
71 Raw cactus land, sand 
1.40 
.160 
1.40 
5. . 
34 . 
560 . 
555 . 
526 . 
10 . 
13 . 
13 . 
1. 
6. 
and gravel. Calif. 
Trace 
.120 
.64 
0 . 
12 . 
73 Vineyard, sandy loam, 
California . 
0.0 
.120 
.80 
7.4 
70 . 
100 . 
92.6 
30 . 
8. 
74 Sugar beets, sandy 
loam, Kansas . 
1.2 
.260 
1.60 
26.0 
160 . 
800 . 
77.4 
640 . 
2,000 
The raw cactus land from California, No. 71, was very deficient 
in nitrifying organisms, while the virgin clay soil, No. 69, gave a net 
gain of 70 p. p. m. nitric nitrogen. 
The largest gains in the series were made by the soils from Ar- 
