COTTON 131 



buying factory mixed goods by the guaranteed 

 analysis and not by any particular name or brand. 



Nitrogen is usually about three times as costly 

 as phosphorus and potassium. The prices of 

 these elements vary from year to year, but in a 

 general way one can place the commercial value of 

 nitrogen at fifteen cents per pound and phos- 

 phorus and potassium at five cents per pound. 



In computing relative values of different fertilizers 

 you should bear in mind that 1 per cent means 

 one pound in a hundred, or twenty pounds in a ton. 

 It is also a good plan to base your estimate on the 

 lowest percentage figure, since these more truly 

 represent the true value; the higher ones are 

 usually put there to deceive the purchaser. 



To show the manner of estimating fertilizers, I 

 will use two brands commonly sold on the market: 



No. 1. Guaranteed Analysis. 



Nitrogen 1.60 to 2 per cent. 



Phosphoric acid 7 to 8 per cent. 



Potash, 2 to 2.75 per cent. 



Cost, $30.00 per ton. 



When these percentages are multiplied by 20 we 

 obtain the number of pounds in a ton, and when 

 further multiplied by the value per pound, we 

 obtain the value on the basis of a ton. 



This is shown below : 



Nitrogen 1.60 by 20= 32 Ibs. @15c. =$4.80 



Phosphorus 7 by 20=140 Ibs. @ 5c. = 7.00 



Potassium 2 by 20= 40 Ibs. @ 5c. = 2.00 



Commercial value per ton $13.80 



