253 EXPERIMENTAL FARMS 



4 GEORGE V. r A. 1914 



to advantage. The chief products of this rendering or reduction, as it is called, are 

 oil and a scrap or refuse characterized by a high percentage of nitrogen and hence 

 of considerable value as a fertilizer. The process, in the outline, is as follows: — 



On bringing in the fish, the livers are removed and the remainder softened 

 and ' digested ' in suitable vessels by means of superheated steam.* This 

 causes the greater part of the oil to separate. After drawing off the oil the 

 residue is run through presses, to further exclude oil and get rid of a large 

 proportion of the water, and dried in spiral heaters. 



For the past seven years this scrap has been periodically analyzed in the Farm 

 laboratories at the request of the Department of Marine and Fisheries (the branch 

 of the Government service controlling the reduction works) and the results published 

 for the benefit of farmers in the reports of this Division. During the past year, two 

 samples of this scrap from the works at Canso, N.S., have been submitted to analysis. 



Analysis of Dog-fsh Scrap. 



No. 11268. No. 132-7. 

 Per cent. Per cent. 



Moisture 8-44 3-87 



Nitrogen 8-89 10-80 



Phosphoric acid 2-S8 3-90 



Total mineral matter 8-1 S-00 



Mineral matter insoluble in acid -47 -09 



Oil 21-72 22-19 



In all essential features, these results agree fairly well with those of previous 

 years. They indicate the high manurial value of the scrap, primarily as a source of 

 nitrogen, and secondarily of phosphoric acid. From the natui'e of the material and the 

 method of its preparation, some variation in composition might be expected from 

 time to time — and such has been the case. Hitherto, however, the larger number of 

 pamples have fallen within the following limits: Nitrogen, 7.5 per cent and 9.5 per 

 cent; phosphoric acid, 2.5 per cent and 3.5 per cent. Of the present samples, No. 

 13287 is decidedly superior, both as regards nitrogen and phosphoric acid, to the 

 average output of the works. The value of this scrap in the field as compared with 

 other fertilizers is a matter not yet finally settled. Some farmers in Nova Scotia 

 Lave spoken highly of the response observable on its application, while others report 

 that they have been disappointed in its use. Fish waste, as a rule, is a quick, forcing 

 manure readily nitrifying in warm, moist loams that are moderately light. In cold, 

 heavy, ill-dried clays, however, the setting free of its plant food in available forms 

 would be necessarily slow and consequently upon such there would not be an adequate 

 return the season of application, even though the soil stood in need of nitrogenous 

 fertilizer. It will be noticed that this scrap contains from 20 per cent to 25 per cent 

 of oil. This is objectionable, not because oil is of no manurial value but because its 

 presence in such large quantities retards the decomposition of the refuse in the soil 

 and the setting free of its plant food. Moreover, if large dressings are applied for 

 a number of years, the accumulation of oil may injuriously affect the tilth of the soil. 



Correspondence is invited from those who have tried or who purpose trying this 

 fertilizer; possibly information can be given as to its use that may be of assistance. 

 It is well to bear in mind that it is not a ' complete ' fertilizer ; for many field and 

 garden crops it should be supplemented by phosphatic and potassic fertilizers. The 

 home mixing. of fertilizers is not a difficult matter, and formula? will be suggested to 

 meet various requirements provided particulars are furnished as to the nature of soil 

 and its history as to manuring and cropping and the character of the crop to be 

 grown. 



* The livers being exceedingly rich in oil, which is considered of finer quality than that 

 in the bodies of tha fish, are separately rendered. 



