Apr. 30, 1917 
Fixation of Ammonia in Soils 
153 
Table XVIII shows that the three salts which had little influence on 
the fixation of ammonia in the soil from Riverside, Cal., also had little 
effect on the ammonia-fixing power of the soil from Lordsburg, Cal., 
while the iron, potassium, and aluminium salts, which had a marked 
influence on the ammonia-fixing power of the Riverside soil, were also 
effective in the Lordsburg soil. It would therefore seem that the process 
of fixation in these two soils is somewhat closely related. However, the 
relative effectiveness of the iron, potassium, and aluminium salts appears 
to be somewhat different in the two soils. 
Table XVIII .—Effect of nitrate salts on the fixation of ammonia by a Lordsburg soil 
Time 
nitrate 
salts 
were 
allowed 
to stand 
before 
the 
addition 
of am¬ 
monia. 
Quantity 
and 
strength 
of nitrate 
salt added. 
Nitrogen in ammonium 
sulphate added per 
100 gm. of soil. 
Nitrogen recovered. 
Calcium 
nitrate. 
Magnesium 
nitrate. 
Sodium 
nitrate. 
Ferric 
nitrate. 
Potassium 
nitrate. 
Alumi¬ 
nium 
nitrate. 
Hour. 
Mgm. 
Mgm. 
P.ct. 
Mgm. 
P.ct. 
Mgm.\ P, ct. 
Mgm. 
P.ct. 
Mgm. 
P.ct. 
Mgm. 
P. ct. 
5 c. C.NI2.. 
50.00 
11.60 
23.20 
11. 50 
23.00 
11.40 22.80 
33-90 
67.80 
22.00 
44.00 
38.00 
76.00 
IOC. C. N(2. 
50.00 
11.80 
23.60 
11. 70 
23.40 
11.40 22.80 
42.00 
84.00 
33-50 
67.00 
41.60 
83.20 
EFFECT OF SALTS ON THE SOLUBILITY OF CALCIUM IN SOILS 
During the course of the work on the fixation of ammonia by soils it 
was observed that large quantities of calcium were brought into solution, 
and it was thought that the calcium dissolved by the addition of ammo¬ 
nium salts might bear some relation to the ammonia fixed by the soil. 
Table XIX shows the effect of ammonium, aluminium, sodium, and mag¬ 
nesium chlorids on the solubility of calcium in semiarid and humid soils. 
It is seen that the solutions of these salts invariably dissolved a much 
larger quantity of calcium than did distilled water. 
Table XIX .—Effect of ammonium , aluminium , sodium , and magnesium chlorid on 
the solubility of calcium in semiarid and humid soils 
[Results stated as milligrams of calcium per 100 gm. of soil] 
Locality of 
sample. 
Depth 
from 
which 
sample 
was 
taken. 
Quantity of 
each salt solu¬ 
tion added. 
Wa¬ 
ter 
only. 
Increase over water only. 
NH4CI. 
AlCla. 
A 1 CU 
+ 
NH4CI. 
NaCl. 
NaCl 
+ 
NH4CI. 
MgCls. 
MgCla 
+ 
NH4CL 
Inches. 
0- 6 
7.5 c. C. N(2 of 
6.12 
18.90 
126.18 
130.08 
9-30 
24.18 
30-18 
39-48 
each salt solu¬ 
tion per 100 
gm. of soil. 
6-18 
.do. 
4-2 
27.72 
119. 70 
123. 60 
10. 50 
30.00 
31.02 
47.22 
18-30 
.do. 
4-5 
32.22 
116.82 
126. 42 
10.62 
36.00 
27.60 
54- 60 
30-42 
4-35 
37 - 95 
120.30 
159-75 
ir. 10 
43 - 50 
29. 76 
60.45 
0- 6 
.do. 
6 .45 
29. 85 
113. 70 
1 14 - 75 
8-55 
22.65 
30 .90 
39 - 75 
54-66 
.do. 
4-05 
36. 30 
1*0. 55 
112.50 
7-95 
41-55 
29.40 
56.55 
0— 6 
.do. 
7 - 50 
13. 50 
43. 20 
6-18 
.do. 
4. 80 
6. 30 
42. 00 
18-30 
.do. 
3. 60 
6. 00 
18. 30 
Lordsburg, Cal. 
Do. 
Do. 
Do. 
Riverside, Cal. 
Do.'.. 
Berwyn, Md. . 
Do. 
Do. 
