REPORT OF THE CHEMIST. 163 



SEAWEED. 



(Fucus furcatus. ) 



A sample of sea-weed was received from Mr. Geo. R. Weir, of Smith's Cove, N. S., 

 with a request for a report as to its value as a fertilizer. As large amounts of this ma- 

 terial are easily obtainable by the farmers on both the eastern and western coasts of 

 Canada, it was thought desirable to make an analysis. The chief constituents, includ- 

 ing more particularly those which make sea-weed valuable as a manure, are stated in 

 the following table : — 



'B 



Analysis of Fresh Sea-weed. 



Water 63-49 



Organic matter 27 "93 



Ash or mineral matter T 8"58 



100 00 



Nitrogen -468 



Phosphoric acid -108 



Potash 2-025 



Pounds of Fertilizing Constituents in One Ton of Fresh Material. 



Nitrogen lbs. 9-36 



Phosphoric acid 2 - 18 



Potash 40*50 



This must be considered a valuable manure on account of the potash and nitro- 

 gen it contains. The ease with which it decomposes in the soil, thereby liberating these 

 constituents in a condition at once available for plant use, greatly enhances its value. 

 It is essentially a potassic manure, though to a certain degree it may be called a com- 

 plete fertilizer. For general farm crops, however, it might be supplemented with pro- 

 fit by bone meal, which would supply phosphoric acid. It would make an excellent materi- 

 al for composting purposes, but, if preferred, may be applied at once to the land. As a 

 green manure, it would add largely to the humus in the soil and undoubtedly improve 

 the tilth or mechanical condition of the latter. 



Its best results will be given on open, porous and warm soils. It may be 

 applied at the rate of 20 to 30 tons per acre. 



To save the expense of carrying much useless water, it is advisable to allow the 

 sea- weed to partially dry out on the shore before hauling to the farm. 



When sea-weed is burnt, the organic matter, containing the nitrogen is lost, but 

 the ash, or mineral matter, retains the phosphoric acid and potash. The percentages of 

 important constituents, as obtained in our laboratory, are as follows : — 



Analysis of Ash of Sea-weed. 



Oxide of iron and alumina 66 



Lime 769 



Magnesia 6 ■ 93 



Potash 2361 



Soda 4407 



Phosphoric acid 1 ' 27 



Sulphuric acid . . . 3694 



Soluble silica '67 



The ash is seen to be much richer in potash than ordinary wood ashes. 

 8c— 11$ 



