CYANAMID — MANUFACTURE, CHEMISTRY AND USES 37 



CN. NH, + H, O = 0C<; 



The formation of urea is practically quantitative, and is 

 determined ordinarily solely by physico-chemical means, with- 

 out the participation of organisms. It will be shown later that 

 the transformation of the urea to ammonia is probably effected 

 by bacteria. 



FIRST STAGE OF DECOMPOSITION. 



The form in which the nitrogen exists in Commercial 

 Cyanamid, neglecting for the moment the alterations produced 

 in storage, is calcium cyanamide. It has been known for 

 many years that this salt is not stable in aqueous solution but 

 immediately hydrolyzes to acid calcium cyanamide and calcium 

 hydroxide : 



2CN. NCa + H,0 = (CN. NH)2Ca + Ca (OH), 



Moreover, all investigators agree that the acid calcium 

 cyanamide has but an ephemeral existence in the soil; when 

 applied in normal fertilizer doses the calcium quickly abandons 

 the cyanamide. Lohnis attributes this action to the effect of 

 carbon dioxide in the soil solution, precipitating the calcium 

 as carbonate and setting free the cyanamide: 



(CN.NH),Ca + CO, = 2CN.NH, + CaC03 



Kappen considers the removal of calcium as a physical 

 process of absorption in the soil, with simultaneous hydrolysis 

 to free cyanamide: 



(CN.NH), Ca -f- 2H,0 = 2CN. NH, + Ca(OH),. 



He found, for instante, that when 200 grams of clay soil was 

 shaken with 250 cc. of a solution of lime-nitrogen containing 

 47.8 mg. calcium and 62.2 mg. nitrogen, 39 per cent, of the 

 calcium and only 5 per cent, of the nitrogen was absorbed by 



