October, 1922] fertilizer inspection, 1922 



PRICES OF PLANT FOOD MATERIALS 



Nitrogen 



Phosphoric acid (P2O5) available 



Potash (K2O) water soluble 



Either the unit or the pound method can be used to cal- 

 culate the commercial value of the fertilizer. If we have 

 a fertilizer with the following guaranteed analysis: 

 Nitrogen total 3.00% 



Phosphoric acid (P2O5) available 8.00% 



Potash (K2O) water soluble 2.00% 



By the unit method we find : 



Nitrogen 3 X $6.40= $19.20 



Phosphoric acid available 8X 1.48= 11.84 



Potash (K O) water soluble 2X 1.35= 2.70 



Total commercial value $33.74 



By this method we multiply the per cent, of each plant 

 food by the cost per unit and then add these figures to give 

 the total value. 



Employing the pound method we obtain: 



3X20=Number of pounds of nitrogen in a ton 60 X $0.32 =$19.20 



8X20=Number of pounds of phosphoric acid in a ton 160X 0.074 = 11.84 



2X20=Number of pounds of potash water soluble in a ton 40X 0.0675= 2.70 



Total commercial value $33.74 



The per cent, means the number of pounds in 100 pounds. 

 Since there are twenty hundred pounds in a ton we mul- 

 tiply the per cent, by twenty to find the number of pounds 

 of each plant food in a ton. Then by knowing the value 

 of these per pound, we can figure the value of each plant 

 food per ton. 



BUY HIGH ANALYSIS FERTILIZERS 



The content of available nitrogen, phosphoric acid (PaOg) 

 and potash (K2O) determines the value of a commercial 

 fertilizer. Because it costs just as much to mix, bag and 

 to ship a ton of low grade fertilizer as it does a ton of high 

 grade fertilizer, the cost of the same amount of plant food 

 must be much higher in the low grade fertilizer. 



The average cost of a 1-8-2 fertilizer the past season was 

 $45.50 and the average analysis 0.97 per cent, nitrogen. 



