18 FARM ARITHMETIC. 



or to a soil, to mix a fertilizer satisfying the requirement. 

 In general this can be done in a great many ways. 

 Usually, however, the materials from which to select are 

 limited in number or are definitely specified. 



Let us make a ton of fertilizer analyzing 8-3-3, using 

 for the purpose acid phosphate, sulphate of ammonia and 

 kainit. 



Solution : First find the number of pounds of each element in 

 one ton of mixture. 



Phosphoric acid, 8 per cent or 160 pounds per ton, 

 Nitrogen, 3 per cent or 60 pounds per ton, 



Potash, 3 per cent or 60 pounds per ton. 



Acid phosphate is 14 per cent phosphoric acid. 

 To get 160 pounds of phosphoric acid we must use 160 -f- .14 = 

 1,142 pounds of acid phosphate. 



Sulphate of ammonia is 20 per cent nitrogen. 

 To get 60 pounds of nitrogen we must use 60 -=- .20 = 300 

 pounds of sulphate of ammonia. 

 Kainit, 12.5 per cent potash. 



To get 60 pounds of potash we must use 60 -f- .125 = 480 

 pounds of kainit. 



We now have: 



Acid phosphate, 1,143 pounds 



Sulphate of ammonia, 300 pounds 



Kainit, 480 pounds 



1,923 pounds 

 Unfurnished, 77 pounds 



Total, 2,000 pounds 



The remaining 77 pounds is filler and may be supplied in fine 

 sand, road dirt or any similar material. If we wish to make but 

 100 pounds of 8-3-3 fertilizer, we would take one-twentieth part 

 of each of these amounts. 



56. How many pounds each of acid phosphate, nitrate 

 of soda, and kainit will be needed to make a ton of an 

 8-3-3 fertilizer? 



57. How many pounds of acid phosphate, cottonseed 



