COTTON 



123 



PARTS AND DEMANDS FOB YIELD OF AVERAGE 

 ACRE 



Here we find the average cotton crop of 190 pounds 

 of lint draws from the soil 40 pounds of nitrogen, 

 16 pounds of phosphorus, and 25 pounds of potas- 

 sium. But stems, roots, leaves, and bolls are re- 

 turned to the soil, and are therefore not really taken 

 from the land at all. Lint and seed are taken 

 away, and are removed from the land. Now what 

 draft is made on the soil ? Let us see, and at the same 

 time compare with corn and wheat on the basis of 

 the average yield of each crop per acre. 



We have the following facts: 



