6 N. H. AGR. EXPERIMENT STATION [Bulletin 210 



izers should be sold within the state, but they can be used 

 to determine the relative value of the different brands which 

 may be offered to the purchaser. 



PRICES OF PLANT FOOD MATERIALS 



Per unit Per pound 



Nitrogen $7.20 $0.36 



Phosphoric acid (P,0-,) available 2.04 0.102 



Potash (K,0) water soluble 1.00 0.05 



Either the unit or the pound method can be used to 

 calculate the commercial value of the fertilizer. If we 

 have a fertilizer with the following guaranteed analysis : 

 Nitrogen total 3.00 7o 



Phosphoric acid (P2O5) available 8.00% 



Potash (K2O) water soluble 2.00% 



By the unit method we find: 



Nitrogen 3X$7.20 = $21.60 



Phosphoric acid available 8X 2.04= 16.32 



Potash (K^O) water soluble 2X 1.00= 2.00 



Total commercial value $39.92 



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 60X$0.36 =$21.60 



8X20 = Number of pounds of phosphoric acid in a ton 160X0.102= 16.32 



2X20 = Namber of pounds of potash water soluble in a ton 40X0.05 = 2.00 



Total commercial value $39.92 



The per cent, means the number of pounds in 100 

 pounds. Since there are twenty hundred pounds in a ton 

 we multiply 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 



It costs just as much to mix, bag and deliver a ton of 

 low analysis fertilizer as it does a ton of high analysis. 

 For this reason the cost of the plant food must be much 



