I 3 2 
Journal of Agricultural Research 
Vol. VII, No. 3 
ate with the soil in amounts indicated by the titrations. While these 
data are not extensive, a valuable correlation is suggested. 
So far as the writers are aware, this is the first time that this electro¬ 
metric titration has been applied to soil studies. It is believed that with 
further work a valuable means may be developed for the more exact 
determination and adjustment of soil reaction. Hence, this method may 
be extremely useful in the accurate control of soil reaction in many field 
and pot experiments. The somewhat complicated nature of the appara¬ 
tus and the time involved would doubtless militate against its general 
adoption for routine analyses. 
EFFECT OF THE* ADDITION OF NEUTRAL SALTS ON THE HYDROGEN- 
ION CONCENTRATION OF SOIL SUSPENSIONS 
The effect on the H-ion concentration of soil suspensions produced 
by the addition of neutral salts is a matter of considerable theoretical 
interest and of practical importance. Such data may be of significance 
in their relation to the application of soluble fertilizing salts and to the 
various lime-requirement methods dependent upon treatments with 
solutions of potassium nitrate. The desirability of similar measurements 
as correlated with the effects of soluble salts on the physical condition of 
soils has already been suggested by one of the authors (31). The bear¬ 
ing of the results upon adsorption phenomena will be discussed in a 
later section of this paper. 
Table VII records the changes in H-ion concentration of various soil 
suspensions when treated with different neutral salts: 
Table VII .—Effects of neutral salts on H-ion concentration of soil suspensions 
Quan¬ 
tity 
of soil. 
Quan¬ 
tity 
of salt. 
Original soil. 
Treated soil. 
Soil 
No. 
Water. 
Salt added. 
Volt¬ 
meter 
read¬ 
ing. 
H-ion (gram 
molecules 
per liter). 
Volt¬ 
meter 
read¬ 
ing. 
H-ion (gram 
molecules 
per liter). 
16. . 
Gins. 
2 
. C.c. 
30 
Potassium chlorid. 
Cm. 
I 
0. 628 
a 9X10“* 
0. 582 
O. 5 XI6” 4 
16. . 
2 
30 
Sodium chlorid... 
I 
.628 
.9X10- 5 
• 57 2 
.8X10- 4 
16. . 
2 
30 
Barium chlorid... 
I 
.628 
.9X10- 6 
•555 
.2X10- 3 
20. . 
2 
30 
Potassium chlorid. 
I 
■ 639 
• 5Xicr s 
*575 
• 7XIO- 4 
20 . . 
2 
30 
Sodium chlorid... 
I 
•639 
.5X10- 5 
.568 
1. oX io“ 4 
20. . 
2 
30 
Barium chlorid... 
I 
•639 
.5X10- 5 
. 564 
. 1Xio“ s 
15 • • 
2 
3 ° 
Potassium chlorid. 
I 
• 598 
• 3X10- 4 
.548 
. 2 X10" 3 
IS • * 
2 
5 o 
Sodium chlorid.,. 
5 
• 598 
• 3X10 4 
• 55 i 
. 2 Xio” 3 
i 5 - • 
2 
3 ° 
Barium chlorid... 
1 
•598 
• 3X10 4 
•535 
• 3Xio“ 3 
18. . 
2 
3 ° 
Potassium chlorid. 
1 
. 69O 
• 7X10- 6 
. 614 
. 2X10” 4 
18. . 
2 
3 ° 
Sodium chlorid... 
1 
. 69O 
• 7X10- 8 
.615 
. 2 Xio“ 4 
18. . 
2 
30 
Barium chlorid... 
1 
. 69O 
.7X10- 6 
■ 590 
.4X10" 4 
14. . 
2 
3 ° 
Potassium chlorid. 
1 
* 753 
. 6Xio -7 
. 662 
.2X10- 5 
14. . 
2 
30 
Sodium chlorid... 
1 
*753 
.6X10 7 
. 672 
.2X10- 5 
14. . 
2 
30 
Barium chlorid... 
1 
• 753 
. 6X10” 7 
.654 
.3X10- 5 
1. . . 
2 
So 
Potassium chlorid. 
5 
• 7 6 3 
.4X10- 7 
•763 
.4X10" 7 
