CONTENT OF FERTILIZERS 



45 



Principal potash materials used in fertilizers in the United States, 1900 and 1905 



Fertilizer Formulas and Guarantees (Voorhees) 



Probably more than nine-tenths of the fertilizers used in this country 

 are purchased in the form of mixtures containing all three of the essen- 

 tial constituents, nitrogen, phosphorus, and potassium. The various 

 brands are prepared from formulas designed to be especially suitable for 

 different crops and soils. This method of purchase saves labor and 

 thought on the part of the farmer, but the cost of the constituents is 

 greater than if the fertilizer materials are bought and home-mixed; 

 besides, in the mixtures the farmer does not always obtain such pro- 

 portions of the constituents as are best adapted to his conditions. 

 These mixed fertilizers, as a rule, are, and should always be, accom- 

 panied by a statement of guaranteed composition. This is very essen- 

 tial, because purchasers are unable to tell, by mere visual inspection, 

 what kinds and proportions of fertilizing materials have entered into 

 the mixture. In many states the laws require that the source of the 

 materials also shall be distinctly stated, in order to insure the use of 

 good products, as the mixing permits the disguising of poor forms, 

 especially of those containing the element nitrogen. 



Guarantees, however, sometimes confuse the purchaser, because the 

 method of stating the guarantee is such as to mislead, provided he does 

 not understand the meaning of the terms, or is unable to convert the 

 percentages into their equivalents. It is entirely legitimate, when there 

 are no laws forbidding, for the manufacturer to guarantee ammonia, 



