30 FARM ARITHMETIC. 



of phosphoric acid 22 pounds, of potash 61 pounds, or 

 an aggregate of 149.5 pounds of the three. 



Plant Food Removed. A certain farm this year will 

 harvest 10 acres of corn yielding an average of 32>^ 

 bushels of shelled corn to the acre. Estimate that there 

 are 2.86 pounds of stover for each pound of corn to get 

 the average yield of stover an acre. The average corn 

 crop for the whole United States is computed by the 

 Orange Judd crop reporting bureau of the American 

 Agriculturist as averaging 30 bushels an acre on 100 

 million acres, making a total of three billion bushels. 



You will learn by answering the questions below how 

 much plant food is taken away from the farm, if either 

 the corn or the stover is sold. On the other hand, if the 

 grain or the stover is fed on the farm, and the manure 

 therefrom returned to the soil, only a small part of the 

 plant food in the crop is taken away from the land. This 

 is one reason why it is better to feed a crop on the farm 

 and sell the resulting meat, wool, milk, butter or cheese, 

 than to sell off the whole crop. 



Questions. 



1. Determine the number of pounds of nitrogen, 

 phosphoric acid and potash in the shelled corn, in the 

 stover, and in both together for the 10 acres above re- 

 ferred to. 



2. What was the total weight of the United States 

 crop of corn stover in 1912 if all the stalks on every 

 acre were properly field-cured and taken care of? 



3. Then calculate the number of pounds of nitrogen, 

 phosphoric acid, and potash, in the grain, and in the 

 stover, and add both quantities together to get the total 

 amount of plant food consumed by a three billion bushel 

 corn crop. 



