CYANAMID — MANUIPACTURE, CHEMISTRY AND USES 8l 



the sugar cane, in baskets, was watered one month and two 

 months respectively after planting, with solutions of lime- 

 nitrogen (6 per cent, calcium carbide), pure cyanamide, 

 CN.NH2, basic calcium cyanamide, urea and dicyandiamide. 

 The solutions contained each an amount of nitrogen equivalent 

 to an application of 75 pounds per acre. The pure cyanamide 

 proved very toxic and two out of three plants were killed after 

 the second application. About two weeks after the second 

 application, probably when the cyanamide had been converted 

 to other forms, the remaining plants in this basket began to 

 grow luxuriantly. The basic calcium cyanamide caused the 

 plants to look sick temporarily, and they remained inferior. 

 The dicyandiamide (98.5 per cent, pure) was not as intense 

 in its action as pure cyanamide, causing no destruction, but 

 the bad effects lasted longer than those of pure cyanamide, and 

 the plant seemed to lack nitrogen nourishment. The urea 

 caused luxuriant growth from the time of application, and was 

 slightly better than the sulphate of ammonia and lime-nitrogen 

 applications. The lime-nitrogen and sulphate of ammonia 

 solutions produced full growth and were equally effective. 



It appears therefore, that the fertilizing value of lime- 

 nitrogen, decidedly can not he judged from the fertilising 

 action of pure cyanamide or pure calcium cyanamide, and that 

 the fertilizing value of impure dicyandiamide is quite different 

 from the fertilizing value of pure dicyandiamide. It seems 

 that the plant is unable to utilize these pure compounds of 

 nitrogen, but that in lime-nitrogen there are some substances 

 that neutralize such toxic compounds, or help remove them, or 

 that act upon the plant in such a way as to enable it to with- 

 stand the toxic properties until they are destroyed by the con- 

 version of the cyanamide and its polymers by the catalytic 

 action of the soil. It is quite possible for instance, that the 

 lime and the extremely finely divided carbon in lime-nitrogen 

 may play a part in the rapid decomposition of the cyanamide. 

 It is also possible that the urea, and other derivatives that are 

 so easily formed from cyanamide, furnish the plant with 



