THE NITRIFYING EFFICIENCY OF CERTAIN COLORADO SOILS 
27 
tion of the nitrifying organisms rather than to denitrification. The net 
gains in nitric nitrogen varied from 2.13 per cent, to 51.69 per cent, 
of those secured from ammonium sulphate with the corresponding 
soils; compared with the returns from ammonium carbonate, the third 
series, the gains varied from 3.49 per cent, to 37.28 per cent.; with 
dried blood, the fourth set, they varied from 4.00 per cent, to 57.22 per 
cent The average net gain in nitrate nitrogen for the positive soils was 
120.88 p. p. m., with the maximum of 428.0 p. p. m. and a minimum 
of 20 p. p. m. „ 
SERIES III.. Ammonium Carbonate 
Ammonia nitrogen was supplied in the form of ammonium car¬ 
bonate to the third set of samples. The results of the study appear in 
TABLE NO. 3.—Nitrification of Ammonium Carbonate by Colorado Soils. Nitrogen in Parts Per Million 
of Air-dried Soil as Nitrites and Nitrates from 100 m.g. Nitrogen as (NHyCO,, 
Duration of Experiment: 6 Weeks at 28 Degrees C. 
Nitrogen as nitrites Nitrogen as nitrates Chlorin 
__ r o , , in parts per million in parts per million in 
Number of Sample and _a _^ r _____ A. _ p. p. m. 
Description 
75 Wheat field, clay, nor- 
Check 
at 
begin. 
Check 
at 
end 
(NH ) CO., Check 
added at 
begin. 
Check 
at 
end 
(nh 4 ) 2 co 3 
added 
Total 
gain 
Net 
gain 
mal . 
76 Truck garden, river 
.88 
.36 
.152 
7. 
64. 
720. 
713. 
656. 
500. 
bottom loam, normal 
77 Oat field, clay loam, 
1.20 
.002 
.08 
54. 
110. 
680. 
626. 
570. 
400. 
niter . 
78 Raw land, adobe 
.32 
.26 
.08 
26. 
76. 
600. 
574. 
524. 
4,500. 
hill . 
79 Apple orchard, red 
.36 
.60 
.04 
140. 
140. 
100. 
—40. 
—40. 
700. 
clay loam, niter .... 
80 Apple orchard, clay 
.26 
.60 
.32 
5. 
66. 
560. 
555. 
494. 
1,000. 
loam, niter . 
81 Barren field, brown 
.28 
.90 
48.00 
13. 
50. 
36. 
23. 
—14. 
10.000. 
crust, niter . 
82 Barren field, clay 
.32 
.22 
.60 
1360. 
1360. 
1240. 
—120. 
—120. 
32,400. 
niter . 
83 x\pple orchard, heavy 
1.60 
.80 
.20 
46. 
120. 
700. 
654. 
580. 
9,800. 
clay, niter . 
84 Apple orchard, heavy 
.02 
.36 
.20 
6. 
100. 
672. 
666. 
572. 
58. 
clay, niter . 
85 Apple orchard, clay 
.14 
.52 
.02 
Trace 
68. 
700. 
700. 
632. 
138. 
loam, niter . 
86 Oat field, sandy loam, 
.012 
.10 
3.60 
6. 
60. 
400. 
394. 
340. 
1,000. 
niter . 
87 Apple orchard, clay 
.0 
.14 
.06 
130. 
240. 
200. 
70. 
—40. 
6,400. 
loam, niter . 
88 Apple orchard, clay 
.1 
.12 
5.60 
6. 
40. 
340. 
334. 
300. 
202. 
loam, niter . 
89 Apple orchard, sandy 
.40 
.14 
.80 
70. 
100. 
100. 
30. 
0 . 
8,300. 
loam, niter . 
90 Apple orchard, sandy 
.40 
.60 
.12 
180. 
260. 
600. 
420. 
340. 
1,600. 
loam, niter . 
91 Apple orchard, heavy 
.32 
.40 
.40 
13. 
60. 
660. 
647. 
600. 
140. 
clay, normal . 
92 Oat field, sandy loam 
.32 
.14 
.32 
Trace 
40. 
700. 
700. 
660. 
80. 
niter . 
93 Peach orchard, heavv 
1.40 
.20 
.10 
320. 
320. 
340. 
20. 
20. 
7,800. 
clay, normal . 
94 Apple orchard, clay 
.60 
.60 
1.40 
4. 
48. 
640. 
634. 
592. 
120. 
niter . 
95 Apple orchard, brown 
.14 
1.20 
9.60 
34. 
92. 
700. 
666. 
608. 
420. 
surface . 
96 Peach orchard, sandy 
.26 
.14 
.12 
600. 
640. 
1320. 
720. 
680. 
150 
loam, normal . 
97 Apple orchard, clay, 
.24 
1.00 
8.00 
20. 
60. 
120. 
100. 
60. 
170. 
niter . 
.36 
1.40 
1.00 
20. 
132. 
1280. 
1260. 
1148. 
65. 
