CYANAMID — MANUFACTURE, CHEMISTRY AND USES 85 



and carbon dioxide, especially when stored in small quantities. 

 It is possible that a great many investigators have purchased 

 lime-nitrogen at a certain analysis, have allowed the material 

 to remain exposed to the atmosphere several months, and 

 have then weighed out the fertilizer for the test, assuming that 

 its analysis is practically the same as when it was bought. 

 The error introduced by the weighing up of the fertilizer one 

 month after analysis may amount to 5 to 8 per cent, of the 

 total nitrogen, in the case of a single bag exposed in a damp 

 climate. In America, where the Cyanamid is completely 

 hydrated, the error is much less (see p. 27), but it is 

 still large enough to make it desirable to have the fer- 

 tilizer weighed out shortly after the analysis is determined. 



Another error is the application of Cyanamid only a short 

 time before the harvest. Since Cyanamid may take 70 to 80 

 days^ to be completely utilized, it is obvious that the maximum 

 efficiency is obtained only when the application is made not 

 less than 70 to 80 days before the harvest. 



The main purpose of a fertilizer test is to determine the rela- 

 tive profits that can be made by the use of different fertilizers. 

 In view of the difficulties of experimentation, and the danger 

 of drawing unwarranted conclusions from insufficient or 

 irrelavant data, as pointed out above, probably the only fair 

 test of a fertilizer is obtained when it is applied under the con- 

 ditions that prevail where the consumer uses it. All other 

 methods require special proof that the results obtained experi- 

 mentally would also be obtained practically, and such proof 

 is not always available. 



To illustrate the considerable variation in the results 

 obtained with different materials in different conditions, a few 

 of the results of prominent investigators are give here. Thus, 

 Strohmer, with sugar beets, obtained as an average of 7 fields, 

 100 pounds of sugar when sodium nitrate was used, to 104 



^ Dr. A. Frank, private communication. 



