6 4 



FUNDAMENTALS OF AGRICULTURE. 



cent, nitrogen. For crops it has about the same value 

 and effect as nitrate of soda. 



4. Fish Scraps. This is the dried refuse from fish 

 canneries and from the manufacture of glue. Fish 

 scrap and fish make good fertilizers, for they act 

 quickly because of their rapid decay. 



5. Tankage. This is the refuse from slaughter 



CORN GROWN WITHOUT FERTILIZER. 



houses and consists of meat, bone, etc. (from which 

 the fat has been extracted), and dried blood. Like 

 cotton-seed meal, it is suited for crops having a long 

 growing season. It is a brown powdery substance and 

 possesses a strong odor. It is variable in composition 

 and generally contains from 6 per cent, to 10 per cent, 

 nitrogen. 



Fertilizing Materials Containing Phosphoric Acid. 

 The phosphoric acid fertilizers are derived princi- 



