14 



FARM ARITHMETIC. 



always consider the amount of actual plant food present 

 in a commercial fertilizer and must be familiar with the 

 percentage of each food element contained. In order to 

 use such materials wisely and economically one must 

 know something of the nature of the soil in question and 

 of the crop to be grown. 



Mixing fertilizing materials. Fertilizing materials 

 may be used singly or in combination. By properly select- 

 ing the materials a fertilizer may be made to suit any soil 

 and any crop. 



41. A ton of home-mixed fertilizer is made of 1,200 

 pounds of acid phosphate. 400 pounds of cottonseed meal 



; 'J'. '*••< Without Nirrogeo. .;;^*;;^>■■':/;."-^.vlV''^-'■■^V^^^^^^ Radon of Nitrogen. •'^'■•;\'*' ^';*^ .r. ■ y^ ■ • ... Full . R»t*t>^ of Nitrogen.^. . ■ ■ ;^ -;.■.. 





Chancing the Timothy Ration. 

 All three were fertilized alike with muriate of potash and acid phosphate. 



and 400 pounds kainit. What will be the quantity of 

 nitrogen, phosphoric acid and potash ? 



Solution : Turning to page 12 we find that acid phosphate ana- 

 lyzes 14 per cent phosphoric acid; cottonseed meal 7 per cent 

 nitrogen. 2.5 per cent phosphoric acid and 1.5 per cent potash ; and 

 kainit 12^ per cent potash. 

 Acid phosphate. 



1,200 X -14 = 168 Pounds phosphoric acid. 



Cottonseed meal. 



400 X -07 = 28 Pounds nitrogen, 



400 X -025 = 10 Pounds phosphoric acid, 



400 X -015 = 6 Pounds potash. 



Kainit. , . , 



400 X -125 = 50 Pounds of potash. 



