6. FARM ARITHMETIC. 



Solution: 



.019 X 2,000 pounds = 38 pounds Nitrogen 



.007 X 2,000 pounds = 14 pounds Phosphoric acid 



.004 X 2,000 pounds = 8 pounds Potash 



7. When corn yields 40 bushels an acre, how many 

 pounds of nitrogen are removed from each acre of soil? 

 Phosphoric acid? Potash? 



Solution: If a bushel of shelled corn weighs 56 pounds, 40 

 bushels will weigh 40 times 56 pounds 2,240 pounds. 



.019 X 2,240 pounds = 46 pounds Nitrogen 



.007 X 2,240 pounds = 16 pounds Phosphoric acid 



.004 X 2,240 pounds - 10 pounds Potash 



Note. In the above examples, as well as in those to follow, 

 the answers should not be carried out to a greater number of 

 significant figures than are shown in the table. The reason for 

 this is obvious. 



8. A hundred bushels of wheat, weighing 60 pounds 

 a bushel, would represent the removal from the soil of 

 how much nitrogen ? How much phosphoric acid ? How 

 much potash? 



9. A 20-acre field of wheat yielded 32 bushels an acre. 

 What was the draft per acre upon the soil for nitrogen? 

 For phosphoric acid? For potash? For the three com- 

 bined ? What was the total amount of each of these three 

 important elements removed from the field? 



10. When oats yield 50 bushels (32 pounds each) an 

 acre, what is the draft upon the soil for these three ele- 

 ments ? 



11. What is the draft when cotton yields one-half bale 

 (a bale weighs 495 pounds) an acre? When timothy 

 yields two tons an acre? When potatoes yield 100 bushels 

 (60 pounds each) an acre? 



12. Jerry Moore of South Carolina, a member of 

 the Boys' Corn Club, raised 228^4 bushels of corn in 1910 



