CYANAMID — manufacture:, CHEMISTRY AND USES ^J 



these other derivatives is urea, and the balance is amidodi- 

 cyanic acid, melamine and ammeline. (See also p. 29). 



Conversion in Soil. — The chemical behavior of dicyandiamide 

 in the soil has not been studied in the thorough manner in 

 which that of cyanamide has been studied, and much of the 

 data at hand is invalidated by the fact that enormous quanti- 

 ties of nitrogen were used. It is necessary to draw our con- 

 clusions solely from the vegetation tests that have been 

 reported. 



A review of these culture tests will show that they fall into 

 two classes ; one, in which chemically pure dicyandiamide was 

 used, and the other in which home-made dicyandiamide was 

 used. 



Among the prominent investigators who used pure dicyan- 

 diamide are Wagner, Kappen, Sabaschinkofif, Lohnis, Brioux, 

 and C. J. Milo. Their results show that chemically pure 

 dicyandiamide has practically no fertilizing value but 

 on the other hand may have slight toxic action if more 

 than 45 pounds of dicyandiamide nitrogen per acre is applied. 

 The results are in such agreement that it will not be necessary 

 to quote them here. Among those who used dicyandiamide 

 prepared in their own laboratories are Perotti, Ulpiani, R. 

 Inouye and K. Aso. They found that home-made dicyandia- 

 mide has a fertilizing value equal to that of ammonium sul- 

 phate provided it is not used in quantities exceeding 100 

 pounds of nitrogen per acre. 



Perotti,^ for instance, in pot tests with wheat, grown to 

 maturity, obtained the maximum crop with 75 pounds of nitro- 

 gen per acre i-n the form of home-made dicyandiamide. The 

 increase in yield over the control pot without nitrogen was 

 about 100 per cent. With buckwheat the maximum crop was 

 obtained with 150 pounds of nitrogen per acre, and the in- 

 crease in yield was abojit 200 per cent. With flax the maximum 

 yield was with 300 pounds of nitrogen, and the increase in 

 yield was about 60 per cent. 

 1 Cent. Bakt. XVIII, 55, 1907. 



