CHAPTER II 



FERTILISERS CONTAINING NITROGEN 



The Importance of Nitrogen — Evidence that Plants cannot utilise 

 the Free Nitrogen of the Atmosphere — Ammonia and Nitric 

 Acid in the Atmosphere — Origin of the World's Stock of 

 Combined Nitrogen — Nitrogen-fixing Bacteria — Fixation of 

 Atmospheric Nitrogen to form Calcium Cyanamide — Fixation 

 of Atmospheric Nitrogen in the Electric Arc ; Manufacture of 

 Nitrate of Lime — Nitrate of Soda: Nature and Origin — 

 Properties of Nitrate of Soda : Use as a Fertiliser — Value of 

 the Soda Base — Injurious Effects of Nitrate of Soda upon the 

 Texture of the Soil — Sulphate of Ammonia : Sources and 

 Production — Changes undergone by Sulphate of Ammonia in 

 the Soil — Acidity of Soil induced by Sulphate of Ammonia — 

 Relative Value of Nitrate of Soda and Sulphate of Ammonia 

 — Other Nitrogenous Fertilisers : Soot, Shoddy, Fur and 

 Feather Waste, Hoofs and Horns — Slow Action of such 

 Manures — Seaweed. 



Amongst the elements of the nutrition of the plant 

 the first place must be given to nitrogen ; not only does 

 it cost more per pound to the farmer than do the other 

 necessary elements, but as a fertiliser applied to ordinary 

 soils it seems to have a more direct and immediate 

 effect upon the plant ; furthermore, it differs from the 

 others in that plants live habitually in contact with a 

 vast unusable store of it. Since plants live in an 

 atmosphere four-fifths of which consists of elementary 

 nitrogen, it is perhaps necessary to justify a little the 



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