74 CYANAMiD — manufacture;, che:mistry and use:s 



can Cyanamid it is in the form of calcium hydroxide and 

 carbonate. The effects of the lime in either form upon plant 

 life have been stated clearly by Wagner in the extract quoted 

 above. Since the amount of total calcium in Cyanamid, ex- 

 pressed as CaO is about 55 per cent, and the amount applied 

 to the soil is necessarily limited by the amount of nitrogen 

 applied, the lime can hardly reach such an amount that it 

 will ever interfere with plant growth. 



With regard to the inferior action of Cyanamid on acid 

 moor soils, or on other acid soils, Wagner states that the same 

 thing is true of ammonium sulphate, and that the bad effects 

 should be attributed to the abnormal soil conditions and not 

 to any abnormal action of the fertilizer. Soils which are acid 

 are as a rule unfit for profitable agriculture, and should be 

 put into good condition by previous judicious liming. Fer- 

 tilizers cannot be expected to overcome the harmful effects of 

 abnormal conditions which constitute the limiting factor in 

 the growth of a crop. The abnormal conditions must be cor- 

 rected before fertilization will be most economical. Cyanamid, 

 therefore, should not be applied to very acid soils with the 

 expectation of obtaining a profit, unless the unfavorable con- 

 ditions are corrected by previous liming. The quantity of 

 lime in Cyanamid, while of some assistance, is evidently insuffi- 

 cient on very acid soils, which require frequently as much 

 as one to two tons of slaked lime in order to restore them to 

 a neutral reaction. 



The unfavorable action of Cyanamid on very acid soils has 

 frequently been attributed to the possible formation of dicyan- 

 diamide from the calcium cyanamide. That there is no chem- 

 ical or experimental basis for this explanation will be shown 

 in the next section. 



DICYANDIAMIDE. 



The subject of dicyandiamide has been much discussed in 

 chemical literature. It has been necessary, in order to gain 

 a logical understanding of the subject, to select from the mass 



