106 



THE FARMERS HANDBOOK. 



Though a poor manure, it is fairly rich in nitrogen and potash, its weak 

 point being its phosphoric acid. For this reason a previous dressing of the 

 soil with superphosphate or bone-dust is stated to be beneficial. Its use 

 must be avoided on certain crops, such as tobacco, which is injuriously 

 affected by chlorides, which are present in sea weed in considerable quantities 

 in the form of common salt. For the same reason, plants such as asparagus, 

 and small fruit, such as raspberries, which require much saline matter, are 

 benefited by its use. Potatoes are said to contain less starch when manured 

 with sea-weed, and to acquire in consequence a somewhat soapy taste ; at 

 the same time, in many parts of the coast of Ireland, sea- weed is almost 

 the only manure used by the peasant for his potato crop. 



It must be carefully spread, especially if used as a top-dressing for 

 meadows, as it is otherwise liable to destroy the grass when used in large 

 quantities. 



Storer, in his work on " Agriculture," points out that it is entirely free 

 from seeds of weeds, spores of fungi, and eggs of insects ; consequently it is a 

 comparatively easy matter to keep the land clean where it is used. 



The ash of sea- weed contains a considerable quantity of fertilising 

 materials, potash, and phosphoric acid, and in some cases it may be found 

 economical to utilise sea-weed in this form. The nitrogenous matter is, of 

 course, thereby lost. The ash is richer in fertilising substances than wood- 

 ashes — the potash varies in the different varieties from 4 to as high as 20 

 per cent. 



Except for the larger amount of water contained in it, sea-weed compares 

 favourably with farmyard manure. 



The average composition of cow-manure is roughly :— 



Water 77*0 per cent. 



Nitrogen .. ... ... ... *5 ,, 



Potash -6 



Phosphoric acid ... ... ... '15 ,, 



The following table shows the composition of the most abundant species of 

 sea-weeds, determined by Messrs. Wheeler and Hartwell, of the Rhode Island 

 Experiment Station, who have also collected a large amount of valuable 

 information as to the use of these plants : — 



Ribbon-weed, Kelp, Tangle ( Laminaria saccharina) 87 99 



Broad-ribbon weed, Broad-leaved Kelp, Devil's 

 apron Tangle (Laminaria digit ata) 



Dulse, Dilisk (Rhodymenia palmata) 



Round-stalked rock-weed, AscophyUum (Fucus) 

 nodosum ... 



Flat-stalked rock-weed (Fucus vesiciUoswt) 



Irish or Carragheen Moss (Chondrus crispus) 



Eel-grass, grass-wrack (Zostera marina) ... 



