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HIGH-GRADE FERTILIZERS. 



Fertilizers may also be divided into high-grade and low-grade materials. 

 Nitrate of soda, sulphate of ammonia, and dried blood are, for example, standard 

 or high-grade nitrogenous materials. They are so classified because they are 

 fairly constant in composition and furnish nitrogen in some constant and definite 

 form, which will act the same under like conditions. Further, they are rich in 

 nitrogen and the element is immediately or quickly available to the plant. Ground 

 rock phosphates differ in this respect from the above mentioned nitrogenous sub- 

 stances, because, in the raw state, the phosphoric acid for which they are valued, 

 though present in large quantities and quite constant and definite in its form 

 of combination, is not available to plants. After it has been treated with sulphuric 

 acid and converted into superphosphate it is high-grade, owing to the fact that 

 tlie phosphoric acid has been rendered available. 



The various German potash salts, such as muriate of potash, sulphate of 

 potash, etc., are also high-grade, since the composition of each grade and kind 

 is practically uniform in its content of potash, which will always act the same 

 under all conditions, and since they are richer in potash than any other potassic 

 compounds suitable for making fertilizers. 



LOW-GRADE FERTILIZERS. 



The products which are included in the second class differ from the first, 

 in that they may not only vary in their composition, but the constituents con- 

 tained in them do not show a uniform rate of availability. Different samples of 

 bone derived from the same source, treated in the same way, and ground to the 

 same degree of fineness, would be high-grade, but because these conditions differ, 

 bone from various sources cannot be depended upon to act the same under similar 

 climatic and soil conditions. The same is true of tankage; but it varies also in 

 the proportion of its two main constituents, nitrogen and phosphoric acid, and 

 in the rate at which they become available to plants. In this class we must also 

 place fish scrap, wood ashes, and the miscellaneous substances that may be used 

 in building nip mixed or complete fertilizers. 



GUARANTEES. 



It is, therefore, evident that mdxed fertilizers manufactured from these two 

 classes of raw material differ in value; for the nitrogen from nitrate of soda or 

 dried blood will act quicker and is worth more than that from ground leather or 

 horn. In the making of the ordinary complete fertilizers of commerce, in which 

 nitrogenous, potassic, and phosphatic materials are all mixed together, it is im- 

 possible for the purchaser to judge of the nature of the materials used by the 

 appearance, weight, or smell of the mixture, and, furthermore, he can form no 

 idea of the probable amount of plant food constituents present. 



To aid in the intelligent purchase of fertilizers the Dominion Government 

 have enacted a law whereby it is made illegal for any manufacturer or manu- 

 facturer's agent to offer for sale any fertilizer without giving a guarantee of the 



