<384 



Manures in October. 



[Oct., 



citric acid, ground to such a fineness that 80 per cent, or more 

 passed through a sieve containing 100 meshes to the linear 

 inch. The slag now available to the farmer is different, and the 

 position is more complex. There are three different grades : — 



1. The pre-war slag — the so-called Bessemer slag — of which there may 



be some, but not a great deal. 



2. A lower grade containing phosphorus equivalent to 15-30 per cent. 



of tri-calcic phosphate. 80 per cent, being soluble in 2 per cent, citric 

 acid. There is a considerable quantity of this. It is often described 

 as low grade high soluble slag. 



3. A still lower grade, containing phosphorus equivalent to 15-20 per 



cent, of tri-calcic phosphate, but largely insoluble in 2 per cent, citric 

 acid — less than 20 per cent, usually dissolving. A considerable 

 amount of this is obtainable ; it is sometimes described as fluorspar 

 slag, but more usually as low grade low soluble slag. 



To some extent farmers may have to accept whichever of 

 these grades they can obtain. The change in character of the 

 slag has been going on for several years, but it came into 

 prominence during the 'War, and is permanent. Agricultural 

 experts in various parts of the country are testing the new 

 materials and are obtaining reliable information for farmers. 

 Meanwhile, farmers who are offered a choice of slags will do 

 well to consult their County expert. 



Where supplies of slag cannot be obtained it will be well to 

 inquire from the County expert into the possibility of obtaining 

 suitable mineral phosphates. The name and address of the 

 County expert can be obtained on application to the Ministry 

 of Agriculture, Whitehall Place, S.W.I. 



Potassic Fertilisers. — The position in regard to potassic 

 fertilisers is somewhat interesting. The three pre-war fertil- 

 isers are all obtainable: the sulphate, the muriate and kainit. 

 Of these the sulphate comes from Germany while the muriate 

 and kainit come from Alsace and Lorraine, in addition to the 

 German supplies. So far as is known the Alsatian mines can- 

 not produce sulphate, for which the Stassfurt deposits will 

 always have an advantage. W r hether any British potash will 

 find its way on to farms remains to be seen. The qualities 

 are at least as good as before the War, and some of the French 

 muriate is better than the pre-war material. The potash in 

 pre-war muriate was usually equivalent to 45 per cent, of pure 

 potash (KoO) , while that in the Alsatian muriate is equivalent 

 to 50-60 per cent, of pure potash. There is no doubt that jfche 

 enterprising French company which has undertaken the 

 development of the resources of Alsace-Lorraine will make the 

 best of their potash supplies. 



