Nitrogenous Manures 



oven. Carbure of calcium can also be used mstead 

 of coal and lime. 



The cyanamide of calcium (CaCNg) generally 

 contains from 14 to 21 of nitrogen, so that it may be 

 richer than nitrate of soda and almost as rich as 

 sulphate of ammonia, but often it is equalised for 

 market purposes with the contents of nitrate of soda, 

 say 15-5 per cent. ; moreover it contains 20 per cent, 

 of combined and 40 per cent, of hydrated lime. 



To protect it from the air it is supplied in sacks 

 lined with paper, otherwise it would absorb the 

 moisture and swell, increasing in weight and losmg 

 ammonia. Since it is in granular form it can be 

 handled freely, and may be applied with the dis- 

 tributor. It must be harrowed in immediately to 

 prevent any loss of nitrogen. For this reason it 

 cannot be used as a top dressing. It must also be 

 worked in some time before sowing because it might 

 act unfavourably on the crop when, on account of 

 the action of acids, it liberates its dicyanamide. 



Its reaction is not rapid because the nitrogen has 

 to pass through the ammoniacal state before it be- 

 comes transformed into nitrate, but it is a good 

 manure, usually giving results comparable to those 

 of sulphate of ammonia, sometimes better— thanks, 

 no doubt, to the presence of lime. In peaty soils 

 it has not given good results. Its value may be 

 estimated as about that of sulphate of ammonia 

 and its use is certainly to be recommended. 



For the English market it is made in Sweden 

 and Norway by an English company. It is produced 

 also by a German company, and is used in the manu- 

 facture of gunpowder. 



42 



