CHAPTER XV 



ROTATION SYSTEMS FOR GRAIN FARMING 



ABOUT three fourths of the farmers of central United States are 

 so-called grain farmers. There has always been a large proportion 

 of grain farmers; and, furthermore, there always will be, and al- 

 ways must be, for the world does not live by meat alone, nor even 

 upon meat and dairy products; bread is the staff of life. 



Notwithstanding these well-known facts, whenever the grain 

 farmer of central United States has asked for information as to 

 how he could maintain the fertility of his soil, the reply has always 

 been, " Become a live-stock farmer." While this may or may not 

 be good advice for the individual farmer, it is certainly not good 

 advice for all the farmers of the state or nation. 



On the other hand, grain farming is not only profitable, and 

 often more profitable than live-stock farming, but there are 

 methods, and profitable, practical methods, by which the grain 

 farmer can not only maintain the fertility of his soil, but even make 

 it more productive than it ever was even in its virgin state. 



Let us consider the simple three-year rotation: (i) corn, (2) 

 oats, and (3) clover, which is becoming somewhat common in the 

 Illinois corn belt; or (i) corn, (2) wheat, and (3) clover, the most 

 common crop rotation of Ohio. Of course, as many fields should 

 be provided as there are years in the rotation, so that every crop 

 may be represented every year. 



We may assume yields of 100 bushels per acre of corn and oats, 

 50 bushels of wheat, 4 tons of clover, and 4 bushels of clover seed; 

 or these yields may be divided by two, the same proportions being 

 maintained. With the smaller yields the corn, oats, and clover 

 seed will remove 86 1 pounds of nitrogen; while, in accordance with 

 the average data thus far obtained, we may count that the clover 

 secures 40 pounds of nitrogen from the air for each ton of hay it 



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