CHAPTER IX 



POTASSIC FERTILISERS 



The system of agriculture long in vogue in this 

 country consisted in selling grain and meat from the 

 farm but returning the straw to the land in the form 

 of manure. As the straw contains a large proportion 

 of the potash while the grain and meat contain much 

 phosphate, it is evident that the tendency of the system 

 M^as to keep the potash on the farm and to reduce to 

 a minimum the need for buying potassic fertilisers. 



But with the more varied types of cropping of recent 

 times, and above all the extended growth of potash- 

 needing crops like mangolds, potatoes, and, on the 

 Continent, sugar beet, there has arisen the necessity for 

 applying potash to the soil and for this purpose large 

 quantities of potassium salts were imported prior to the 

 war. These all came from Stassfurt in Prussia, and it 

 was supposed that no other deposits of economic im- 

 portance existed elsewhere. The shutting off of these 

 supplies during the war, however, has led to a systematic 

 and not unsuccessful search for other sources of potash. 

 Natural deposits have been investigated in Alsace, Spain, 

 the AVestern United States, and elsewhere. 



In tliis country blast furnace flue dust has been ex- 

 ploited: it contains potassium compounds deriv^ed from 

 potash which has volatilised from the fuel, ore and flux^. 

 The furnace gases are collected as completely as possible 



^ Journ. Bd. Agric. 1917, xxiv. 526, 852, also Journ. Soc. Chem. Ind. 

 1918, xxxviT. 222 T. 



