132 STATE BO-\RD OF AGRICULTURE. 



Nitrogen in nitrates costs about 15c per lb. 



Nitrogen in ammonia salts " " IT^c per lb. 



Nitrogen in organic matter " " 17c per )b, 



♦Phosphoric acid (available) " " 4c per lb. 



Phospnoric acid insoluble " " 2ic per lb. 



Potash in the form of muriate " " 4|c per lb. 



Potash in the form of sulphate " " 5c per lb. 



Potash in the form of carbonate (ashes) " " 5c per lb. 



HOW TO CALCXn:-ATE VALUES. 



The value of a commercial fertilizer depends entirely on the values of the 

 nitrogen, phosphoric acid and potash present. The following is an example: — 



Analysis. 



Per cent. Valuation. Total value. 



Nitrogen =7.77X20X .17=: $16.22 



Available phosphoric acid =2.40X20X 0.04= 1.92 



Insoluble phosphoric acid =2.10X20X .025= 1.05 



Potash =1.00X20X -05= 1.00 



Total commercial value =$20.19 



As may be seen above all that is necessary to obtain the commercial value is 

 to multiply the amounts shown in the bulletin by 20 and then by the price per 

 pound of that ingredient as recorded in the table of values. 



ACKNOWLEDGMENT. 



The analytical data recorded in this Bulletin have been much accelerated by 

 the efficient assistance of Miss Dorothea Moxness, the assistant in chemistry. Mr. 

 E. A. Boyer assisted also in the work of inspection and analysis. 



♦Note — According to the present methods for the estimation of available phos- 

 phoric acid, considerable not strictly available is included. This is due to present 

 imperfections of the methods for estimating phosphoric acid. For example, in 

 bone meals and phosphate slags varying amounts of phosphoric acid go into so- 

 lution in the citrate reagent according to the temperature and degree of agi- 

 tation of solution and also according to the degree of fineness of the fertilizer. 

 These varying percentages appear in the analytical tables as available phosphoric 

 acid. It is easily seen that a finely ground bone meal must furnish more real 

 available phosporic acid that one coarsely ground. It fact, it might be con- 

 sidered that with a bone meal ground to a flour nearly all of its phosphoric acid 

 would be available. The Association of Official Agricultural Chemists through 

 its referee on phosphoric acid, is investigating this matter and it is expected that 

 a method will soon be formulated doing away with this imperfection. It seems 

 probable that the value of these goods must be estimated on the total amount of 

 phosphoric acid together with the degree of fineness. 



