20 



FERTILIZERS 



The most valuable sources of organic nitrogen, 

 from the standpoints of uniformity in composition, 

 richness in the constituent, and availability, are dried 

 blood, dried meat, and concentrated tankage, fish 

 and animal, which are produced in large quantities 

 in slaughter houses and fish canneries. 



28. The most concentrated form of nitrogen is 

 ammonium sulphate, containing about 19% or 24% 

 of ammonia. Nitrate of soda contains as high as 

 16% nitrogen, blood 14%, hoof and horn meal, 14%, 

 slaughter house tankage from 5% to 10%, raw bone 

 H^%, bat guano 3% to 20%, sea fowl guano 12%. 

 There are numerous other sources of nitrogen, but the 

 above are those most generally used. The contents 

 as given are in terms of nitrogen and approximately 

 the maximum. 



FIGURB 3 THE NITROGEN CYCLE 



