Journal of Agricultural Research 
Vol. I, No. 3 
188 
The percentage of potassium adsorbed from a potassium-chlorid 
solution increases asymptotically as the concentration of potassium 
chlorid decreases and at very low concentrations adsorption is practically 
complete. 
In general, the smaller the soil particles the greater the selective 
adsorption of potassium from a potassium-chlorid solution by the soil. 
The presence of sodium nitrate decreases the adsorption of potassium 
from a solution of potassium chlorid by a soil up to a concentration of 
about 37.5 grams of potassium chlorid per liter and then increases it. 
The presence of monobasic calcium phosphate does not change ap¬ 
preciably the adsorption of potassium from a potassium-chlorid solution 
by a soil. 
Finally, if a mineral fertilizer be applied to a soil and exposed to the 
rain and thus dissolved and carried through the soil in solution, these 
substances will be adsorbed (an entirely physical phenomenon) either as 
a whole or selectively from the solution by the vast surface of the soil 
particles and will be held there by this same physical force until the 
plant or subsequent leaching removes it. 
The presence of other mineral substances added to the soil may or may 
not increase or decrease the rate at which this adsorptive phenomenon 
takes place. 
