•158 EXPERIMENTAL FARMS 



7-8 EDWARD VII., A. 1908 



be considered as increaslrg the store of fertility in the soil. The large amount of 

 potash contained in the pease is to be noted. 



FEKTILIZING MATEEIALS. 



DOG-FISH SCRAP AS A FERTILIZER. 



At intervals during the past year we have undertaken to examine and report upon 

 -samples of dog-fish scrap and dried fish offal for the Department of Marine and Fish- 

 eries. These were forwarded from the dog-fish reduction works at Canso, N.S., and 

 Shippigan, N.B,, at which places there is now a considerable accumulation of this 

 fertilizer, chiefly obtained from the rendering or so-called reduction of dog-fish. This 

 fish, a species of shark, by reason of its voraciousness and the fact that it is present 

 in Atlantic waters in large numbers, has become a serious menace to fisheries on the 

 east coast. To protect the fisheries the Federal Government accordingly offered a 

 bounty for the capture of this pest and, to utilize to the best advantage the fish thus 

 brought in, established the above mentioned works. In this way large quantities both 

 of oil and of a rich nitrogenous fertilizer have been prepared. It is this latter by- 

 product that has been submitted to us to determine its agricultural value. 



The first samples of fish scrap were received on October 3, 1905, from the Dog- 

 fish lieduclion Works, Canso, N.S., marked as follows: jSTo. 1. Fish Offal, September 

 10; No. 2. Dog-fish Scrap (wood dried), September 26; No. 3. Dog-fish Scrap (coal 

 dried), September 25!. 



No. 1. Fish Offal. — This, I presume, is not from the dog-fish, but is the dried 

 refuse obtained in the cleaning of fish — cod, haddock, &c., for drying or salting. 



It contained a large quantity of coarse bone, many fragments being from 1 inch 

 to 1^ inches in length, and is, therefore, not suitable for direct application to the soil. 

 A mechanical separation showed Yl per cent granular material and 29 per cent coarse 

 bone. This scrap would, I think, require grinding before it could be put on the 

 market either for farmers' use or for the matiufacture of commercial fertilizers. 

 From the agricultural standpoint much importance must be placed upon the fineness 

 of the material, as in a very large measure this factor determines the relative avail- 

 ability of the plant food constituents in the scrap. The finer the material, other 

 things being equal, the more ready the decay of the scrap in the soil, and consequently 

 the more quickly are the fertilizing elements offered in suitable forms for crop use. 



Analysis. 



Moisture 11-07 



Nitrogen 8-43 



Phosphoric acid 9-01 



Total mineral matter , .. 24-15 



Mineral matter insoluble in acid (sand, &c.) -93 



Oil 5-47 



These data indicate a scrap of excellent quality, both as regards percentage of 

 nitrogen and phosphoric acid and comparatively low oil content. 



In the United States large quantities of Menhaden (a coarse sort of herring) are 

 used in the manfacture of scrap, and this, with a moisture content of, say, 10 per cent, 

 will contain, as a rule, from 6 to 8 per cent nitrogen, and 6 to 7 per cent phosphoric 

 acid. It is evident, therefore, that this Canadian product compares well in composi- 

 tion with the raw material so largely used by the fertilizer manufacturers as a source 

 of nitrogen and phosphoric acid. 



No. 2 and No. S. Dog-fish Scrap. — These are very similar in appearance, being 

 considerably finer than No. 1, though containing some coarse bone and meat frag- 

 ments. Both are decidedly oily to the touch and sight. For the fertilizer manufacturer 



