96 
Journal of Agricultural Research 
Voi. 26, No. 3 
EXPERIMENT 6.—SOIL+CALCIUM HYDROXID+POTASSIUM CHLORID 
This experiment was performed like Experiment 5, with the exception 
that KC 1 was used in addition to the Ca(OH) 2 . The data obtained are 
presented in Table VI. In comparison with those in Table V, the data 
show clearly that the hydrogen-ion concentration was considerably in¬ 
creased by KC 1 , even when large amounts of Ca(OH) 2 were added. In 
the presence of KC 1 more of the hydrogen ions are liberated from the acid¬ 
forming substances, and more Ca(OH) 2 is required for neutralization, 
The absolute neutral point was passed when between 2 and 3 tons equiva¬ 
lent of CaCO s per acre were added in the form of Ca(OH) 2 . The figures 
for the P H values in Tables V and VI present some variations not easily 
explained, probably due to some disturbing factors not understood. 
Table VI.— Ph on suspensions and extracts of soil-\-Ca(OH) 2 -\-KCl, also titrations 
and calcium content of extract, and calcium adsorbed by soil 
Calcium added. 
Suspension. 
! Extract. 
! Titer 0.05N 
HC 1 . 
Calcium in 
extract. 
Calcium not 
adsorbed. 
Calcium 
adsorbed. 
Mgm. 
Ph- 
Cc. 
Mgm. 
Mgm. 
Mgm. 
0.0. 
5. 02 
! 6.61 
— O. I 
14. O 
0 . 0 
O. O 
2-5 . 
5 - 50 
6. 70 
—. I 
* 5 - 5 
*• 5 
I. O 
5-0 . 
5 - 7 o 
—. I 
16. I 
2. I 
3-9 
8.0. 
6.46 
6. 71 
—. I 
*9 -3 
5-3 
2. 7 
12.0.. 
7. 22 
7- 2 5 
—. I 
21. 1 
7 - 1 
4.9 
16.0. 
7 * 93 
7 - 45 
—. 2 
21. 3 
7-3 
8.7 
20.0. 
8. 50 
7.76 
. 0 
23- 5 
9 - 5 
IO. 5 
28.0. 
9-32 
8. 10 
. O 
26. 5 
! 2 - 5 
15 - 5 
36.0. 
10. 13 
• 5 
29. 6 
15.6 
20. 4 
48.O. 
11. 00 
10. 94 
1. 0 
35 -o 
21. 0 
27. 0 
60.0. 
11. 41 
11. 41 
i -4 
4 i. 2 
27. 2 
32.8 
The calcium in the extract came from that dissolved from the soil by 
KC 1 and also from the added Ca(OH) 2 . The calcium not adsorbed was 
obtained by subtracting 14, the figure obtained when no Ca(OH) 2 was 
added, from each subsequent figure. The figures so calculated for 
unadsorbed calcium are considerably larger than the corresponding ones 
in Table V. When KC 1 is present part of the soil’s capacity for adsorbing 
the base is satisfied, and less calcium is adsorbed. A little over half as 
much calcium was adsorbed in Experiment 6 as in Experiment 5. Even 
this amount of adsorption is large when the large excess of KC 1 is con¬ 
sidered, and it shows the great capacity of the soil for adsorbing calcium. 
(See fig. 6.) 
EXPERIMENT 7.— SOIL-f CALCIUM HYDROXID-f CALCIUM CARBONATE 
The amounts of precipitated CaC0 3 equivalent to the calcium in the 
different portions of Ca(OH) 2 used in Experiment 5 were mixed with the 
various portions of dry soil. The rest of the experiment followed the 
method of No. 5. The data obtained are presented in Table VII. (See 
fig- 5 -) 
