268 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



tons dried, Avith ;i total selliiiii: value of $1,539,810. Of the 45,711 tons 

 l)rodueed fi-oni Delaware uorllnvard, 33,458 tons were acidulated aud 

 12,253 were dried, the average price of the former being 112.87 per 

 ton and the latter $26.22 per ton. South of Delaware the product of 

 green and of acidulated scrap combined, according to the latest 

 returns, was 15,395 tons, wdiile 24,724 tons were di-ied, the respective 

 values per ton being 112.95 and 123.79. 



Only a snuill percentage of the fish scrap is used by the farmers in the 

 condition in Avhich it leaves the factories; most of it is ground and 

 serves as an ingredient in comjiound or so-called " complete " ferti- 

 lizers. Compound fertilizers are prepared at some of the menhaden 

 factories, but as a general thing their jireparation is in the hands of 

 persons who have nothing to do with catching and rendering the fish. 



The value of commercial fertilizers is dependent mainly on their 

 content of nitrogen and phosphoric acid, which are the most impor- 

 tant plant foods usually lacking in the soil. Tlie nitrogen necessary 

 is supplied mainly by fish scrap. Various other materials are also 

 used, as dried blood, meat scrap and other slaughter-house refuse, 

 cotton seed, sulphate of ammonia, nitrate of soda, Peru\ ian guano, etc. 

 The phosphoric acid is supplied by fish scrap to some extent, l)ut 

 principally by the phosphate rocks, boneblack from the sugar refin- 

 eries, bone meal, etc., the solubility of the phosphate being increased 

 by treatment with sulphuric acid, thus making superphosphates. 

 The value of fish scrap varies according to the percentage of ammonia 

 and phosphoric acid contained therein. As a general rule, dried scrap 

 contains about 8 per cent of nitrogen and 8| per cent of phosphoric 

 acid. On a selling basis of 124 per ton, the nitrogen costs about 10 

 cents per pound and the phosphoric acid about 3^ cents per pound 

 for compounding purposes. Other necessary plant foods are potasli, 

 lime, magnesia, sulphuric acid, and iron. These usually exist in suf- 

 ficient (piantities in the soil itself, but are added under special con- 

 ditions, especially the potash. The nature of the ingredients and tlic 

 respective i)roportions required vary according to the soil and the 

 croj) for which the compound is intended. 



Although the agricultural value of dried fish sci-ap is neai-ly equal 

 to tliat of Peruvian guano, the market price is much below that arti- 

 cle. In explanation of this fact it may be stated that fish scrap is not 

 in such compact and good mechanical condition for shipment and gen- 

 eral use. Its value as a fertilizing agent has not been so widely known 

 as that of Peruvian guano, and thus its i)rincipal use is largely limited 

 to the manufacturers of superphosphates, who are forced by compe- 

 tition to exercise great caution in the cost of manufacture. And, 

 f u rt liciiuori!, there is a tendency to reduce the quantity of ammonia and 

 increase that of phosphoric acid and potash in complete fertilizers to 

 meet the re^iuirements of the soil. Other ammcmiated materials now 

 compete with fish guano in the nuiking of superphosphates, aunrng 



