2 BULLETIN 37, U. S. DEPARTMENT OF AGRICULTURE. 



available for fertilizer purposes. There is one striking exception 

 to this generalization. In the destructive distillation of coal for 

 the preparation of gas and coke the nitrogen present in the coal is 

 evolved, in part at least, as ammonia. This is easily recoverable 

 and in the form of ammonium salts constitutes an important source 

 of nitrogen for fertilizer purposes. 



The agronomic necessity which compels the use of nitrogenous fer- 

 tilizers and the scarcity of nitrogenous compounds available for 

 fertilizer purposes together make the nitrogen carriers of extremely 

 great importance. 



The following materials constitute the present source of nitro- 

 genous fertilizers: 



Chile saltpeter, or nitrate of soda. 



Artificial nitrates of soda, lime, and aaimoL ia. 



Sulphate of ammonia. 



Fish scrap. 1 



Tankage. 



Dried blood. 



Cottonseed meal. 



SODIUM NITRATE. 



Sodium nitrate occurs naturally as an impregnation of earthy and 

 saline material, known as caliche, on certain of the arid uplands of 

 the Provinces of Tarapaca, Tacna, Antofagasta, and Atacama, in 

 Chile. The names "Chile niter" and "Chile saltpeter" have been 

 given this product because of its occurrence. 



The composition of caliche is given in Table I. 2 



Table I. — Analysis of caliche from Tarapaca Province, Chile. 



Constituent. 



Proportion. 



Constituent. 



Proportion. 





Per cent. 



60.97 



.73 



16.85 



4.56 





Per cent. 

 1.33 







5.88 







4.06 







5.64 









PRODUCTION AND CONSUMPTION OF SODIUM NITRATE. 



Of the sodium nitrate produced by the Chilean beds during the 

 year 1911, 2,419,700 tons were exported, 1,827,089 tons to European 

 countries 3 and 518,613 tons to the United States. In the United 

 States 70,000 tons of this were used in agriculture. 



* For a discussion of fish scrap see Bull. No. 2, U. S. Dcpt. Agr., " The Fish-scrap Fertilizer Industry 

 of the Atlantic Coast." 



* Pennock, Losses of Combined Nitrogen. J. Ind, Eng. Chem. 4, 1 7 2 (1912). 



* Importations to Egypt are included in this amount. 



