Journal of Agricultural Research 
Vol. IX, No. 7 
190 
The ammonia content of the control soils remained rather constant 
throughout the experiment, but the nitric nitrogen increased slowly and 
somewhat irregularly. At the conclusion of the experiment, the average 
nitrate content in the three soils amounts to 2.61 mgm. per 100 gm. of 
soil, which would be approximately 100 pounds of nitrogen per acre-foot 
of soil. This rate of nitrification would seem to be sufficient to supply 
the needs of any crop. However, if these soils had remained in the field 
undisturbed except by the ordinary cultivation, it is doubtful whether 
the increase in nitrates would have amounted to more than a fraction of 
the gains secured under laboratory conditions. 
On June 23, 1914, three soil samples were secured from Highland, Cal. 
One sample was taken from a productive grove, one from an unpro¬ 
ductive grove, and a third from an adjacent virgin soil. The nitrogen 
changes in these soils following the addition of blood, red clover, or 
alfalfa are shown in Tables III and IV. 
Table III .—Nitrification of dried blood and green manures in soils from Highland , Cal . 
June 2J, IQ14 
[Results expressed as milligrams of nitrogen per ioo gm. of soil] 
PRODUCTIVE SOIL 
Material added. 
Constituent. 
Incubation period. 
7 days. 
14 days. 
21 days. 
28 days. 
35 days. 
42 days. 
Dried blood (1 per cent). 
Ammonia. . 
20. 12 
3 8 - 3 <s 
33-°4 
36.. 40 
32.76 
32. 20 
Red clover (1 per cent). . 
Nitrates. ... 
2. 80 
10. 08 
9.84 
8. 96 
8. 96 
Do.. 
Ammonia. . 
— - . 00 
— . e6 
.28 
— .28 
. 28 
. OO 
Do. 
Nitrates... . 
.84 
* j 
3-48 
5 * 90 
7.64 
9 - 5 2 
II. 48 
Alfalfa (1 per cent) . 
Ammonia. . 
I. 68 
— . 28 
1.12 
. 00 
.56 
•56 
Do . 
Nitrates. ... 
3 * 9 2 
10. 08 
13-44 
14. 84 
16. 24 
15.96 
Water only . 
Ammonia .. 
1. 68 
I, 96 
1. 12 
I. 40 
1.12 
I. 12 
Do . 
Nitrates. ... 
1. 40 
I. 40 
2. 24 
I. 96 
2. 24 
I. 96 
UNPRODUCTIVE SOIL 
Dried blood (1 per cent.. 
Ammonia.. 
32. 20 
38.40 
38.08 
34.88 
34 . 16 
33- 88 
Do. 
Nitrates.... 
.28 
.28 
4. 20 
5.00 
7. 00 
8. 96 
Red clover (1 per cent).. 
Ammonia.. 
— . 28 
- .28 
. 00 
. 24 
. 00 
. 00 
Do...;.. 
Nitrates.... 
1.12 
2. 25 
2. 24 
3. 80 
. 5-6o 
7. 00 
Alfalfa (1 per cent). 
Ammonia.. 
4. 20 
2. 24 
.28 
- 74 
.84 
.84 
Do. 
Nitrates.... 
7. 28 
15. 40 
14. 84 
17. 26 
18. 20 
18. 76 
Water only. 
Ammonia.. 
1. 68 
1. 40 
1. 40 
1. 12 
1. 40 
1. 12 
Do. 
Nitrates_ 
1.12 
1. 40 
1. 68 
1. 80 
1. 96 
1. 68 
VIRGIN SOIL 
Dried blood (1 per cent).. 
Ammonia.. 
21. 28 
26. 32 
29. 40 
37. 86 
29. 48 
28. 00 
Do. 
Nitrates.... 
1.12 
8. 68 
20. 20 
18. 76 
19. 92 
19. 04 
Red clover (1 per cent).. 
Ammonia.. 
- .28 
.28 
.24 
'.42 
. 14 
. 28 
Do. 
Nitrates. 
.28 
1. 68 
3.08 
7. 28 
7. 96 
11. 48 
Alfalfa (1 per cent). 
Ammonia.. 
— . 28 
.28 
.28 
. 14 
. 28 
. 00 
Do. 
Nitrates.... 
.84 
3 - 9 2 
8. 40 
10. 08 
12. 52 
13. 72 
Water only. 
Ammonia.. 
1. 40 
1.12 
1.12 
.98 
1. 12 
1. 12 
Do. 
Nitrates.... 
1.12 
1. 40 
1. 68 
1. 40 
1. 68 
1. 40 
