COMMERCIAL FERTILIZERS AND THEIR USE 235 



potash as nitrogen and five times as much phosphoric 

 acid as potash. In order to make a ton of such a ferti- 

 lizer it would be necessary to take : 



The ton of fertilizer would contain about 35 pounds 

 of nitrogen, 189 pounds of phosphoric acid, and 53 

 pounds potash. These amounts are determined by 

 multiplying the percentage composition by the weight 

 of material taken : 



POUNDS 



Nitrogen . 225 x 0.155 = 34.9 



Potash 425 x 0.125 = 53.1 



Phosphoric acid 1350 x 0.14 = 189.0 



The fertilizer would contain about 1.75 per cent ni- 

 trogen, 2.65 per cent potash, and 9.45 per cent phos- 

 phoric acid. The percentage amounts are obtained by 

 dividing the total pounds by 20. This fertilizer if made 

 at home from materials purchased in the market, at the 

 prices indicated, would cost, exclusive of transportation 

 and mixing, about $21.47. 



POUNDS COST 



Nitrogen 34.9 @ 16 cents = $5.58 



Phosphoric acid .... 189.0 @ 7 cents = 13.23 

 Potash 53.1 @ 5 cents = 2.66 



Total $21.47 



