29 
the: nitrifying efficiency of CERTAIN COLORADO SOILS 
The addition of the dried blood to the soil appears to have im¬ 
proved the condition for nitrification in several of the samples for 
twenty of them gave gains in nitric nitrogen above the control; one pro¬ 
duced the same and two less. It would lie interesting to know whether 
the increased nitrifying efficiency in these cases has resulted from the 
additional food material or whether the deleterious action of the high 
chlorids has been lessened by some combination with the blood. 
TABLE NO. 4. Nitrification of Dried Blood by Colorado Soils. Nitrogen in /Parts Per Million of 
of Air-dried Soil as Nitrites and Nitrates from 100 m.g. Nitrogen as Dried Blood 
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 
Description 
Check 
Check 
Dried Blood 
Check 
Check 
Dried Blood 
Total 
Net 
p. p. ill . 
at 
begin. 
at 
end 
added 
at 
begin. 
at 
end 
added 
gain 
gain 
75 Wheat field, clay, nor- 
mal . 
.88 
.36 
.30 
7 . 
64 . 
680 . 
673 . 
616 . 
500 . 
76 Truck garden, river 
bottom loam, normal 
1.20 
.002 
.26 
54 . 
110. 
680 . 
626 . 
570 . 
400. 
77 Oat field, clay loam, 
niter . 
.32 
.26 
.88 
26 . 
76 . 
600 . 
574 . 
524 . 
4 , 500 . 
78 Raw land, adobe 
hill . 
.36 
.60 
.64 
140 . 
140 . 
140 . • 
0. 
0. 
700. 
79 Apple orchard, red 
clay loam, niter . . . 
.26 
.60 
1.00 
5 . 
66 . 
640 . 
635 . 
590 . 
1,000. 
80 Apple orchard, clay 
. loam, niter. 
.28 
.90 
88.00 
13 . 
50 . 
100. 
87 . 
50 . 
10,000. 
81 Barren field, brown 
crust, niter . 
.32 
.22 
.84 
1360 . 
1360 . 
740 . 
- 620 . ■ 
— 620 . 
32 , 400 . 
82 Barren field, clay 
niter . 
1.60 
.80 
1.70 
46 . 
120. 
500 . 
454 
380 . 
9 , 800 . 
83 Apple orchard, heavy 
clay, niter . 
.02 
.36 
.08 
6 . 
100. 
600 . 
594 . 
500 . 
58. 
84 Apple orchard, heavy 
clay, niter . 
.14 
.52 
.18 
Trace 
68. 
880 . 
880 . 
812 . 
138. 
85 Apple orchard, clay 
loam, niter . 
86 Oat field, sandy loam, 
.012 
.10 
.26 
6 . 
60 . 
620 . 
614 . 
560 . 
1,000. 
niter . 
87 Apple orchard, clay 
.00 
.14 
.02 
130 . 
240 . 
80 . 
— 50 . - 
— 160 . 
6 , 400 . 
loam, niter . 
88 Apple orchard, clay 
.10 
.12 
35.00 
6 . 
40 . 
320 . 
314 . 
280 . 
202. 
loam, niter . 
89 Apple orchard, sandy 
.40 
.14 
.60 
70 . 
100. 
240 . 
170 . 
140 . 
8 , 300 . 
loam, niter . 
.40 
.60 
5.20 
180 . 
260 . 
480 . 
300 . 
220. 
1 , 600 . 
90 Apple orchard, sandy 
loam, niter . 
91 Apple orchard, heavy 
.32 
.40 
.60 
13 . 
60 . 
600 . 
587 . 
540 . 
140. 
clay, normal . 
.32 
.14 
8.80 
Trace 
40 . 
440 . 
440 . 
400 . 
80. 
92 Oat field, sandy loam 
niter . 
93 Peach orchard, heavy 
1.40 
.20 
.192 
320 . 
320 . 
340 . 
20. 
20. 
7,800. 
clay, normal . 
.60 
.60 
40.00 
4 . 
48 . 
240 . 
236 . 
192 . 
120 . 
94 Apple orchard, clay 
niter . 
.14 
1.20 
4.80 
34 . 
92 . 
400 . 
366 . 
308 . 
420. 
95 Apple orchard, brown 
surface . 
.26 
.14 
.08 
600 . 
640 . 
1000. 
400 . 
360 . 
150. 
96 Peach orchard, sandy 
loam, normal . 
.24 
1.00 
.32 
20. 
60 . 
880 . 
860 . 
820 . 
170. 
97 Apple orchard, clay, 
niter . 
.36 
1.40 
1.20 
20. 
132 . 
880 . 
860 . 
748 . 
65. 
No. 78, from the 
raw adobe hill, 
presents an interesting 
case 
again 
in this series. It will be remembered that in two preceding studies. 
Series I and III, this soil showed active denitrification in the presence 
of the different nitrifiable substances, and that the controls contained 
the same amount of nitrate at the end of the experimental period as in 
the beginning. Here, in place of the reduction of its initial nitrates, it has 
