1906.] Linseed Cake in the United Kingdom. 601 



must be remembered that this is, in many cases, much less than 

 would in theory be expected. In the first place, the value of the 

 manure made from cake depends, as in the case of artificial 

 manures, on the presence of the three ingredients : nitrogen,, 

 phosphoric acid, and potash. But in using artificial manures, 

 one only of these substances or any two of them can be applied 

 in any desired proportion, whereas in cake residues they cannot 

 be thus separated and dealt with. It is, however, a fundamental 

 principle in manuring that the composition of the manure 

 should be regulated by (a) the deficiencies of the soil, or (J?) the" 

 particular requirements of the crop. There are wide areas of 

 pasture in this country which not only require no nitrogen or no 

 potash, but which are actually rendered less valuable by re- 

 ceiving these substances. In cases where a soil contains abund- 

 ance of nitrogen, or where a plant can draw its nitrogen from 

 the air, it is wasteful to supply this element in the manure, as is 

 unavoidable in the case of cake residues containing all three 

 manurial constituents. 



In cake residues, moreover, very great waste takes place in 

 the farmyard manure itself. Lawes and Gilbert put this loss at 

 50 per cent., and this view has been endorsed by Voelcker and 

 Hall. Thus, although the manurial elements of a ton of linseed 

 cake are theoretically worth £2 us. 1 id. as the residues leave 

 the animal, they are worth very much less by the time the farm- 

 yard manure is carried to the land and offered to the crop. Not 

 only is there this loss of manurial value in cake residues before 

 the farmyard manure that contains them reaches the land, but 

 probably no more than one-half of the nitrogen that is left is 

 taken up by the crop to which it is applied. 



The imports of flax or linseed into the United Kingdom 

 have during recent years shown a considerable tendency to 



United Kingdom, therefrom to this country. In the year just 

 ended, however, the quantities were below 

 the level of 1903 and 1904, During the past six years the totals 

 have been as follows : — 



Supply of 

 Linseed Cake 

 in the 



increase, largely in consequence of the 

 development of the cultivation of linseed 

 in Argentina and the increased exports 



