1042 



Synthetic Nitrogenous Fertilisers. [Feb.,, 



Kothamsted during the War — sulphate of ammonia. Some 

 of the results are: — 





Aberdeen. 



Newton Rigg. 



Hay, cwt. per acre. 



Oats. lb. of grain 

 per acre. 



Mangolds, tons 

 per acre. 



1911-14. 



General 

 Average. 



1913. 



3 centres. 



1914. 



3 centres. 



1911. 1914. 



1913. 1914. 



1 



Nitrate of Soda 

 Nitrate of ammonia 

 No nitrogenous top | 

 dressing . . . . j 



5:5-8 

 56-2 



50-2 



69-2 

 69-7 



05-7 



57- 8 

 59-9 



58- 4 



2644 228(1 

 2787 2427 



2477 1853 



m ; 23f 



14| 21* 









Eothamsted, 1918. 





Mangolds. 







Wheat. 







Potatoes. 















Expt. 1. 



Expt. 2. 





/. per ac. 



act. per ac. 



Grain. 



Straw. 



Grain. Straw. 





buslt. 



lb. 



bush. 1 lb. 



Sulphate of i ammonia .. 



18-6 



1754 



413 



5250 



40-1 | 4S30 



Ni crate of ammonia 



233 



174-5 



44-7 



5(170 



3 7-7 ! 5050 



No nitrogenous top dressing . . 



17-3 



100-9 



38-6 



4588 



31-6 1 4520 



In the Aberdeen experiments the ammonium nitrate was 

 somewhat better than nitrate of soda, while at Newton Bigg 

 it was inferior in action ; in the latter case the soda may have had 

 some specific effect. At Eothamsted the ammonium nitrate was 

 better than the sulphate for mangolds, although judging by 

 the character of the haulm it was less suitable for potatoes 

 and might have given less crop had there been disease. It is 

 much more concentrated than sulphate of ammonia or nitrate 

 of soda, containing as a rule about 34.8 per cent, of nitrogen, 

 of which one half is in the form of ammonia and one half 

 nitrate. It must therefore be used sparingly — only J- cwt., or 

 even less, should be applied — and there may be difficulty in 

 ensuring that these quantities are not exceeded. This matter, 

 however, is within the farmers' control. 



Another and more serious difficulty is that ammonium nitrate 

 tends to become wet and form a hard cake, which, however, is 

 readily broken with a wooden mallet. Some kinds used to become 

 very damp, but technical chemists learnt a good deal during 

 the War and found ways of mitigating this disadvantage. The 

 factor that will finally determine whether ammonium nitrate 

 remains on the market as a fertiliser is the cost. If nitrate of 

 soda is obtainable at £20 per ton, nitrate of ammonia is worth 



