58 THE SOIL SOLUTION 



find that even if the solution in the soil were dependent on the 

 solubility of the soil minerals alone and were continually tend- 

 ing towards a definite normal concentration, actually this con- 

 centration would seldom if ever be realized. Most important in 

 this connection is the fact that the concentration of the soil so- 

 lution is always dependent in some degree upon the concentra- 

 tion of the soluble constituents in the solid phases in other than 

 definite chemical combinations. Other factors affecting the con- 

 centration of the mineral constituents in the soil solution are 

 always existent, and theoretically at least, can not be ignored. 

 Nevertheless a priori reasoning as well as the experimental 

 evidence at hand indicates that the various processes taking place 

 in the soil as a whole continually tend to form and maintain a 

 normal concentration of mineral constituents in the soil solution. 



