Journal of Agricultural Research 
Vol. I, No. 3 
186 
As was expected, since the removal or adsorption of potassium from 
a potassium-chlorid solution is undoubtedly a surface phenomenon, in 
general the smaller the soil particles the greater was the adsorption of 
potassium. Clay, however, in spite of the fact that the particles are 
smaller than those of the other types of soil, does not show a corre¬ 
spondingly greater adsorptive power, the surface of the clay particles 
being probably of a different nature. The classification of the different 
types of soil is based entirely on their mechanical analysis. 1 
SERIES No. s 
In series No. 5, 35-gram portions of Marshall silt loam (the same as 
that used in experiment III) were placed in 200 c. c. bottles with solutions 
containing varying amounts of potassium chlorid per liter. To some of the 
portions 10 grams of sodium nitrate were added, while to others 10 grams of 
monobasic calcium phosphate were added. These were treated as in 
experiment III. A solution containing 58.25 grams of potassium chlorid 
per liter in contact with calcium phosphate alone lost an amount of 
potassium during contact equivalent to 0.0500 gram of potassium 
chlorid per 100 c. c. The results of the analyses of the supernatant 
liquids are given in Table IV. 
Table IV .—Effect of the presence of other substances on adsorption. 
Experiment No. 
Quantity of KC 1 equiva<- 
lent to the quantity of K 
per 100 c. c. of solution. 
Loss. 
Before 
contact. 
After 
contact. 
Per 100 c. c. 
of solution. 
Percent¬ 
age. 
A.—With 10 grams of NaNO a present: 
Grams . 
Grams . 
Grams . 
I. 
11. 1850 
* 0 - 3750 
0. 8100 
7 - 25 
II. 
8.9950 
8. 2650 
. 7300 
8. 12 
Ill. 
6.2400 
5.6600 
. 5800 
9 - 30 
IV. 
4.4270 
3-9470 
. 4800 
10. 83 
V......... 
2.0450 
1. 7140 
•33OS 
16. 15 
VI. 
. 8270 
•5950 
. 2320 
28. 05 
B.—With 10 grams of CaH 4 (P 0 4 ) 2 present: 
I. 
11. 1100 
10. 5700 
. 5400 
4. 86 
II. 
9. 1300 
8. 6200 
* 5 IO ° 
5 - 59 
Ill. 
6. 3400 
5.8500 
. 4900 
7 - 73 
IV. 
4 - 5830 
4.1200 
.4630 
10.10 
V. 
L 993O 
1. 5480 
•4405 
22. 10 
VI. 
.QIQO 
. 5500 
.3690 
40. 15 
C.—With 5 grams of NaN 0 3 present: 
I. 
6 - 3950 
5. 8200 
* 5750 
9. 00 
D.—With 5 grams of CaH 4 (P 0 4 ) 2 present: 
I. 
6. 3850 
5. 9000 
. 4850 
7. 60 
Table IV and figure 2 show that the presence of sodium nitrate at con¬ 
centrations of potassium chlorid below about 37.5 grams per liter 
1 Fletcher, C. C , and Bryan, H. Modification of the method of mechanical soil analysis. U. S. Dept. 
Agr., Bur. Soils, Bui. 84, 1912. 
