12 



FARM ARITHMETIC. 



Carriers of phosphoric acid. Acid phosphate is the 

 principal material supplying phosphoric acid alone. It 

 ordinarily carries 14 per cent phosphoric acid. 



33. How many pounds of actual phosphoric acid in a 

 ton of acid phosphate? 



34. Suppose you desire to apply 35 pounds of actual 

 phosphoric acid to your soil, how many pounds of acid 

 phosphate will it require ? 



Carriers of potash. Muriate of potash, sulphate of 

 potash, and kainit are commercial forms supplying potash 

 only. The per cent of potash in each is shown in the 

 table following: 



Material Per cent of Potash 

 Muriate of potash, 50 



Sulphate of potash, 48 



Kainit, 12.5 



35. How many pounds of actual potash in a ton of 

 muriate of potash ? Sulphate of potash? Kainit? 



36. Suppose you desire to apply a mixture of these 

 three materials to your land so as to get 30 pounds of 

 actual potash ten pounds from each material how 

 many pounds of each will be necessary ? 



Carriers of more than one kind of plant food. Lead- 

 ing fertilizing materials and per cent of each element car- 

 ried is shown in the table below : 



