214 



NITROGENOUS FERTILIZERS 



In nitrifying, the ammonia is changed to nitric acid, and 

 sulphuric acid is set free. Both acids require bases to 

 neutralize them, and thus there is twice as much lime or other 

 base needed for this fertilizer as is needed for other nitrog- 

 enous materials undergoing nitrification. Lime is used up 

 very rapidly and acidity results (Section 186). 



III. NITROGEN AS AMINE OR PROTEIN 



160. Cyanamid or Lime Nitrogen. — The utilization of 

 atmospheric nitrogen in the manufacture of fertilizers is 

 successfully accomplished in another way than by making 

 calcium nitrate. The process depends on the fact that nitro- 

 gen unites with calcium carbide to form calcium cyanamide 

 at a temperature of about 1000° C. In the soil this com- 



Fig. 51. — Plant of American Cyanamid Co., Niagara Falls, N. Y. 



pound changes gradually to nitrate. This fertilizer goes 

 under a variety of names. Cyanamid is the trade name of the 

 American product manufactured at Niagara Falls (Fig. 51). 

 Calcium cyanamide is a common name for it, although as a 

 matter of fact the fertilizer contains only about 45 per 

 cent, of this compound. Lime nitrogen is another name; 



