FIXATION 



195 



the soil. Many fertilizers, if they did not undergo this 

 process, would be injurious to crops, for there would be 

 an abnormal amount of soluble alkaline or acid com- 

 pounds which would be destructive. When the process 



FIG. 39. Plants grown in Normal Soil. 



of fixation takes place, it removes, to a great extent, 

 injurious water-soluble salts, particularly when the reac- 

 tion is one of union rather than replacement. Then 

 the plant is free to render soluble its own food in quan- 

 tities and at times desired. 



Farm manures and commercial fertilizers alike un- 

 dergo the process of fixation and, in studying ferti- 

 lizers, their action upon the soil and the products of 

 fixation are matters of prime importance. 



