112 
Journal of Agricultural Research 
Vol. at, No. 3 
EXPERIMENT 22 .—P H OBTAINED BY ADDING VARYING AMOUNTS OF CALCIUM HYDROXID 
TO DIFFERENT SOILS 
By adding Ca(OH) 2 to a soil in such a way that several definite but 
varying amounts are used, and then determining the P H values of the 
different portions, it should be possible to determine the equivalent 
CaC 0 3 needed in the form of Ca(OH) 2 to give any desired P H value. A 
number of the soils used in Experiment 21, the initial P H number of 
which was less than 7, were selected for this experiment. Varying 
amounts of the Ca(OH) 2 solution and enough KC 1 to make the concen¬ 
tration 0.5N were added to three portions of soil. The amounts of Ca(OH) 2 
to be added to the different soil portions were judged partly from the 
initial P H value obtained on the soil suspension in KC 1 solution and 
partly by the general character of the soil. The solution was left in 
contact for the usual 24 hours. The results are given in Table XXII. 
The figures are grouped according to the decreasing value of the hydrogen- 
ion concentration. 
Table XXII .—Changes in Ph values produced by adding Ca(OH ) 2 to different soils 
Soil 
No. 
County. 
Soil type. 
31 
27 
49 
II 
23 
25 
13 
15 
17 
33 
Allen. 
_do. 
Montgomery 
Allen. 
-do. 
_do. 
_do. 
Riley. 
Brown. 
Allen. 
Oswego fine sandy loam 
Osage clay. 
Crawford clay. 
Summit silt loam. 
Neosho silt loam. 
Osage loam. 
Oswego silt loam. 
... .do.. 
Marshall silt loam. 
Summit silt loam. 
53 
5i 
21 
Brown. 
Leavenworth 
Harper. 
Marshall silt loam 
Brown loam. 
_do. 
57 
41 
39 
43 
Barton. 
Jewell. 
....do . 
Greenwood 
Greensburg sandy loam 
Colby silt loam. 
Lincoln clay. 
Crawford silt loam. 
Calcium added, mgm. 
0 
8 
it 
24 
Ph 
4. 82 
4. 82 
4. 82 
5. 06 
5. 06 
5. 06 
5. 16 
5 - 33 
5 * 40 
5 * 46 
Ph 
6. 14 
5 - 87 
6. 31 
6 . 34 
6. 61 
6. 75 
6. 64 
6.64 
6. 20 
6.37 
Pa 
7-35 
6 - 95 
7 - 39 
7 - 3 2 
7 - 5 2 
7. 66 
7-49 
Ph 
8. 03 
7 - 56 
7.96 
8. 67 
8. 72 
7.96 
7.76 
7-83 
8. 40 
7 - 49 
7 - 73 
Calcium added, mgm. 
0 
4.8 
9.6 
14.4 
5 - 5 o 
6. 04 
6. 10 
6. 20 
6. 61 
7-25 
6-95 
7. 08 
7. 86 
7 - i 5 
7 - 59 
8. 56 
Calcium added, mgm. 
0 
2.4 
4.8 
7.20 
6. 07 
6. 34 
6. 44 
6.44 
6. 58 
6- 75 
6- 75 
6-95 
7. 12 
7. 20 
7. 12 
7. 08 
7. 46 
7 - 49 
7-35 
7 - 32 
There is in general a relationship between the initial hydrogen-ion 
concentration and the P H values produced by the addition of a certain 
amount of Ca(OH) 2 . If the initial hydrogen-ion concentration is high, 
a given amount of Ca(OH) 2 will produce a smaller change than if the 
