1921.] 



Synthetic Nitrogenous Fertilisers. 



1037 



SYNTHETIC NITROGENOUS 

 FERTILISERS. 



E. J. Russell, D.Sc, F.R.S., 

 Director of the Rothamsted Experimental Station. 



A synthetic substance is one that is prepared from its 

 elements; synthetic nitrogenous fertilisers, therefore, are those 

 produced in the factory from their elementary constituents 

 instead of being obtained as by-products of some manufactur- 

 ing process, as is the case with sulphate of ammonia. 



So far as the farmer is concerned it is quite immaterial how 

 the fertiliser is made so long as it contains no harmful ingre- 

 dients, and his chief interest is to obtain adequate supplies at 

 as low a cost as possible. The name " synthetic " is there- 

 fore of manufacturing interest but of no agricultural consequence. 



It so happens that the fertilisers which the manufacturers 

 find it easiest to make are rather different from those now 

 obtainable. It would be quite easy to manufacture nitrate of 

 soda in the factory, and the product would have the same 

 fertiliser value as the natural nitrate imported from Chili, but 

 it is rather easier for the manufacturer to prepare nitrnte of 

 lime; hence this course is adopted. Similarly, sulphate of am- 

 monia could be prepared synthetically without much difficulty; 

 it is, however, easier to make chloride of ammonia, and it is 

 likely, therefore, that this fertiliser will be produced. Each 

 of these fertilisers, in addition to giving increases in crops, 

 has some special property which may be of value to the farmer, 

 while the widening of the sources of supply is of course of 

 considerable importance at the present time. 



The question of making synthetic fertilisers was first 

 opened by the late Sir ^Yilliam Crookes in 1898 in an address 

 to the British Association, which at once caused a great deal 

 of discussion. Sir William pointed out that the population 

 was increasing more rapidly than the area under wheat, and 

 consequently a time must come when wheat supplies would 

 be insufficient unless the production per acre could be rni^ed. 



