JOURNAL OF AGRHET1AL RESEARCH 
DEPARTMENT OF AGRICULTURE 
Vol. I Washington, D. C., December io, 1913 No. 3 
SELECTIVE ADSORPTION BY SOILS 
By E. G. Parker, 
Scientist, Soil Laboratory Investigations, Bureau of Soils 
From the standpoint of soil chemistry the absorption of material from 
the air and the soil solution by the soil is of first importance. The ab¬ 
sorptive power of a soil enables it to retain the soluble salts necessary 
to plant life in spite of the leaching effect of rains and the movement of 
the soil solution toward the surface of the soil in dry weather, and thus 
to store up soluble material, either natural or applied in the form of a 
so-called fertilizer, for the future needs of crops. 
The absorptive properties of soils have been under investigation in the 
Soil Laboratory for several years under the direction of Dr. Frank K. 
Cameron, and several publications 1 describing this work have appeared 
from time to time. The object of the work described in this paper was 
to obtain clearer insight into the mechanism of adsorption phenomena, 
particularly selective adsorption, and the characteristic effects of one 
solute upon the adsorption of another. 
It is a well-known fact that either by leaching or by shaking a soil with 
a solution of potassium chlorid (or some neutral salt) the amount of 
potassium present will be diminished, and a certain amount of the bases 
of the soil (Ca, Mg, etc.) will be found in the resulting solution, while the 
amount of the chlorin will remain practically unchanged. Also, the re¬ 
sulting solution is slightly but distinctly acid to our common indicators. 
On treating kaolin with solutions of magnesium and sodium chlorids 
Kohler 3 found the resulting solutions to be slightly but distinctly acid 
1 Cameron, F. K., and Bell, J. M. The mineral constituents of the soil solution. U. S. Dept. Agr., Bur. 
Soils, Bui. 30, 1905. 
Cameron, F. K., and Patten, H. E. The distribution of solute between water and soil. Jour, of Phys. 
Chem., v. 11, p. 581-593, 1907. 
Patten, H. E. Some surface factors affecting distribution. Trans. Amer. Electrochem. Soc., v. 10, 
p. 67-74. 1906. 
Patten, H. E., and Gallagher, F. E. Absorption of vapors and gases by soils. U. S. Dept. Agr., Bur. 
Soils, Bui. 51, 1908. 
Patten, H. E., and Waggaman, W. H. Absorption by soils. U. S. Dept. Agr., Bur. Soils, Bui. 52,1908. 
Schreiner, Oswald, and Failyer, G. H. The absorption of phosphates and potassium by soils. U. S. 
Dept. Agr., Bur. Soils, Bui. 32, 1906. 
2 Kohler, Ernst. Adsorptionsprozesse als Faktoren der Lagerstattenbildung und Lithogenesis. Ztschr. 
Prakt. Geol., Jahrg. 11, p. 49-59. 1903- 
Journal of Agricultural Research, Vol. I, No. 3 
Dept, of Agriculture, Washington, D. C. Dec. 10, 1913 
H—1 
17072“—13-1 
(179) 
