Jan. 2, 1917 
Availability of Potash in Orihoclase-Bearing Soils 
25 
SOLUBILITY OF THE POTASH IN SOILS OF THE RIVERSIDE AREA AS 
INFLUENCED BY CALCIUM HYDRATE AND CALCIUM SULPHATE 
A large sample of virgin soil from the site of the new University of 
California Citrus Experiment Station at Riverside was collected, dried 
in the sun, and passed through a i-mm. sieve. Portions of this soil of 
100 gm. each were weighed out and 500 c. c. of distilled water added, 
together with varying amounts of calcium hydroxid, as shown in Table V. 
The mixtures were shaken until the solutions had reached equilibrium. 
The amounts of potash found in the solutions are given in Table V. As 
in the case of the pegmatite arid orthoclase experiments, the addition of 
calcium hydroxid does not modify the solubility of the potash in this 
soil sufficiently to be detected in the analyses. 
Table V. —Effect of solutions of calcium hydrate on the solubility of the potash in soil 
from the Citrus Experiment Station site 
Solution No. 
Calcium oxid 
in 100 c. c. of 
solution. 
Potassium 
oxid in 
solution. 
I.:. 
Gm. 
0. 00 
. 0103 
. 0207 
. 0414 
. 0621 
. 0828 
• io 35 
a . 1242 
P. p . m. 
26. 4 
26. 4 
28.8 
28.8 
24. 0 
27. 6 
2 K . 2 
27. 6 
2. 
3... 
O' 
4. 
c. 
D 
6 . 
7. 
8. 
& Solid phase present. 
The solubility of the potash in the soil from the Citrus Experiment 
Station site in the presence of varying amounts of calcium sulphate 
was also determined. The concentration of the calcium-sulphate solu¬ 
tions and the amount of potash found in solution are given in Table VI. 
Table VI. —Effects of solutions of calcium sulphate on the solubility of the potash in soil, 
from the Citrus Experiment Station site 
Solution No. 
Calcium sul¬ 
phate in 100 c. c. 
of solution. 
Potassium 
oxid in 
solution. 
I. . 
Gm. 
O. OO 
. 017 
• 034 
.068 
. 102 
. I36 
. 17O 
a .210 
P. p.m. 
24 
24 
26 
29 
26 
26 
29 
26 
2. 
4 , . . .. 
6 .....* 
7.. 
8... 
a Solid phase present. 
