oct. 20,19*3 Soil Reaction in Relation to Calcium Adsorption 
hi 
Table XXI.— Hydrogen-ion concentration and calcium content of soil and subsoil —Con. 
Surface. 
Subsoil. 
Soil 
No. 
County. 
Soil type. 
Cal¬ 
cium 
in HC 1 
solu¬ 
tion. 
h 2 o 
sus¬ 
pen¬ 
sion. 
KC 1 
sus¬ 
pen¬ 
sion. 
Cal¬ 
cium 
in HC 1 
solu¬ 
tion. 
H2O 
sus¬ 
pen¬ 
sion. 
KC 1 
sus¬ 
pen¬ 
sion. 
J 3 
Allen. 
Oswego silt loam.... 
Mom. 
25 -3 
P B - 
5-43 
p B - 
5.16 
Mom. 
30.6 
p B - 
5 - 33 
Pjff. 
5. 02 
53 
Brown. 
Marshall silt loam. . . 
30.9 
5-43 
5 - 5 o 
29.4 
5 - *9 
4. 99 
5 i 
Leavenworth. . 
Brown loam. 
33*2 
5- 66 
6. 04 
23.O 
5-43 
4. 99 
57 
Barton. 
Greensburg sandy 
26.3 
5 - 93 
6. 07 
112. O 
8. 00 
8. 06 
47 
21 
39 
41 
Cherokee. 
Harper. 
Jewell. 
.do. 
loam. 
Oswego clay. 
Brown loam. 
Lincoln clay. 
Colby silt loam. 
39-8 
14. 2 
42. 2 
27. 2 
5 - 97 
6. 07 
6. 27 
6. 41 
6.17 
6. 10 
6.44 
6. 34 
154.2 
16.8 
54-8 
78. 0 
7. 08 
6. 78 
6. 71 
7. 66 
6.98 
6.51 
6. 68 
7. 66 
19 
43 
Brown. 
Greenwood.... 
Osage silt loam. 
Crawford silt loam... 
59-3 
31.8 
6. 41 
6. 48 
6. 54 
6. 64 
105. 0 
78. 0 
7-39 
6.85 
7.76 
6.85 
35 
Finney. 
Richland silt loam. . 
34 - 1 
6.81 
6. 98 
138.0 
7.76 
7 . 90 
29 
Allen. 
Oswego silt loam.... 
68.2 
6. 98 
7. 08 
209. 0 
7.71 
7.66 
45 
Greenwood.... 
Crawford clay. 
324.0 
7-49 
7.76 
431.0 
7.69 
7.69 
27 
Jewell. 
Lincoln silt loam.... 
192. 0 
7-49 
7. 86 
136.0 
7 - 56 
7*73 
55 
Gove. 
Colby silt loam. 
78.4 
7-49 
7.96 
284. 0 
7.90 
8. 23 
The P H values on the soil suspensions in water and in the KC 1 solu¬ 
tion do not differ widely except as will be noted. Hoagland and Sharp 
(23) found that the diffusion of KC 1 into the electrode vessel had a 
tendency to increase the H-ion concentration, the amount of increase, 
however, was small. It should be remembered that in soils P H numbers 
have no significance beyond the first decimal place. Considering the 
different P H values obtained, the general rule seems to be that the pres¬ 
ence of KC 1 increases the concentration of the H ion or the OH ion when 
either is in marked excess. That is, in very acid soils the presence of 
KC 1 will increase the hydrogen-ion concentration, while in alkaline soil 
it will increase the hydroxyl-ion concentration. If the P H value obtained 
is between 6 and 7 the influence of KC 1 is small. 
As a rule, the calcium content is higher in the subsoil than in the 
surface soil, and a higher calcium content is accompanied by a lower 
hydrogen-ion concentration. There were five soils which were exceptions 
to this, namely: 
No. 13, Oswego silt loam. 
No. 17, Marshall silt loam. 
No. 33, Summit silt loam. 
No. 51, Brown loam. 
No. 53, Marshall silt loam. • 
In these the differences in calcium content of soil and subsoil were 
small. As a rule, the calcium content exerted a greater influence on the 
reaction than did the difference between soil and subsoil. When the 
calcium content was high the P H values ranged between 7.5 and 8.0, 
which is also near the values obtained when adsorption of calcium from 
Ca(OH) 2 was complete. 
