CONTENTS. 



Introduction, 



Soil used in the experiments, 



Method of investigation, 



Absorption of ammonia, . 



Absorption of dyes, 



Calcium oxide removed, . 



Sodium and potassium removed. 



Sulfuric acid removed. 



Hydrochloric acid removed. 



Nitric acid removed. 



Iron and aluminium removed, 



Calcium absorption, 



Analysis of drainage waters. 



Culture studies, 



Summary and conclusions. 



PAGE 



73 

 74 

 75 

 75 

 76 

 77 

 ■ 78 

 80 

 80 

 80 

 80 

 82 

 84 



Approved by the State Board of Publication. 



