New York Agricultural Experiment Station. 609 



mercial valuation may have a higher agricultural value; while, for 

 another crop on the same soil, or the same crop on another soil, 

 the reverse might be true. 



Rule for Calculating Approximate Commercial Valuation of Mixed Fer- 

 tilizers on Basis of Trade-Values for 1913. 



Multiply the percentage of nitrogen by 3.8. 



Multiply the percentage of available phosphoric acid by 0.9. 



Multiply the percentage of insoluble phosphoric acid (total minus available) by 0.4. 



Multiply the percentage of potash by 1.0. 



The sum of these 4 products will be the commercial valuation 

 per ton on the basis taken. 



Illustration. — The table of analyses shows a certain fertilizer to 

 have the following composition: Nitrogen 2.52 per ct.; available 

 phosphoric acid 6.31 per ct.; insoluble phosphoric acid .89 per ct.; 

 potash 6.64 per ct. According to this method of valuation, the 

 computation would be as follows: 



Nitrogen 2 . 52 x 3 . 8 $9 . 58 



Available phosphoric acid 6.31x0.9 5. 70 



Insoluble phosphoric acid 0.89 x 0.4 0.36 



Potash 6.64 x 1.0 6.64 



$22.28 



This rule assumes all the nitrogen to be organic and all the pot- 

 ash to be in the form of sulphate. If a considerable portion of 

 nitrogen exists in the fertilizer as nitrate of soda or as sulphate of 

 ammonia, and potash is present as muriate, the results are some- 

 what less. 



Farmers should be warned against judging fertilizers by their 

 valuations. A fertilizer, the cost of which comes chiefly from the 

 phosphoric acid present, would value much lower commercially 

 than a fertilizer with a high percentage of nitrogen, and yet the 

 former might be the more profitable one for a given farmer to 

 purchase. 



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