AOUATIC PRODUCTS AS FERTILIZERS. 



GENERAL REVIEW. 



A fertilizer is aii}' substance added to the soil for the purpose of 

 producing a better growth of crops. The food required by plants is 

 supplied in part from the atmosphere, but principally from the soil. 

 If the supijly of any one of the necessary ingredients be deficient, a 

 small crop is the result; and the puri^ose of fertilizers is to supply the 

 plant-foods lacking in the soil. 



The general use of fertilizers is of comparatively recent origin, yet 

 the ijreparation of these substances supports an extensive industry, 

 employing a large amount of capital and many thousands of men. 

 Compared with the immense quantities of barnyard materials, phos- 

 phate rooks, etc., the use of aquatic products for fertilizer is relatively 

 small, yet it is by no means unimportant in the fishery industries. 



Fish, seaweeds, shells of moUusks and crustaceans, and various 

 other aquatic products have long been known to possess rich fertiliz- 

 ijig properties. All kinds of fish can be used for this purpose; but, 

 owing to the greater value of choice species as food, only the non- 

 edible ones and the waste parts are utilized. The menhaden is the 

 onlj' fish taken in great quantities in this country especially for con- 

 version into fertilizer. The output of this species is verj^ large, 

 amounting to 30 per cent of the total catch of fish in the United 

 States, and its capture maintains one of the most extensive and vig- 

 orously prosecuted of the American fisheries. Compared with that 

 from menhaden, the quantity of fertilizer made from other fish is 

 small, and only such are used for this purpose as can not be profitably 

 employed in any other way. 



The original use of fish for fertilizing purposes was in a fresh or 

 green state, and they were added to the soil directl}' after their cap- 

 ture, although, of course, no special effort was made to preserve their 

 fi-eshness. Before the advent of the colonists in America, the Indians 

 were accustomed to manure their small crops of corn b}' placing one 

 or more fish in each hill or by spreading them broadcast over the 

 field, and this practice was followed by the early settlers. Owing to 

 the original richness of the soil and the limited agricultural opera- 

 tions, the use of fertilizers was of comparatively small extent until 



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