238 MISCELLANEOUS FARM SUBJECTS 



Rotation. All crops may be classified under three heads: Ex- 

 haustive, intermediate, and restorative. No crop restores to the soil 

 any very considerable amount of plant food unless it is plowed under 

 for green manure, or is allowed to decay on the surface. In dry 

 farming a rotation of crops is absolutely necessary. The following 

 five and six year rotations have been found to work well in the 

 Great Plains area. 



Five Year Rotation. 



Corn. Wheat, winter or spring. Brome-grass meadow. Brome- 

 grass meadow. Oats, barley, emmer, or wheat. 



Wheat, winter or spring. Brome-grass meadow. Brome-grass 

 meadow. Oats, barley, emmer, or wheat. Corn. 



Brome-grass meadow. Brome-grass meadow. Oats, barley, em- 

 mer, or wheat. Corn. Wheat, winter or spring. 



Brome-grass meadow. Oats, barley, emmer, or wheat. Corn. 

 Wheat, winter or spring. Brome-grass meadow. 



Oats, barley, emmer, or wheat. Corn. Wheat, winter or spring. 

 Brome-grass meadow. Brome-grass meadow. 



Six Year Rotation. 



Corn. Wheat, winter or spring. Seeded to brome-grass. Brome- 

 grass meadow. Brome-grass meadow. Oats, barley, emmer, or 

 wheat. 



Wheat, winter or spring. Seeded to brome-grass. Brome-grass 

 meadow. Brome-grass meadow. Oats, barley, emmer, or wheat. 

 Corn. 



Seeded to brome-grass. Brome-grass meadow. Brome-grass 

 meadow. Oats, barley, emmer, or wheat. Corn. Wheat, winter or 

 spring. 



Brome-grass meadow. Brome-grass meadow. Oats, barley, em- 

 mer, or wheat. Corn. Wheat, winter or spring. Seeded to brome- 

 grass. 



Brome-grass meadow. Oats, barley, emmer, or wheat. Corn. 

 Wheat, winter or spring. Seeded to brome-grass, Brome-grass 

 meadow. 



Oats, barley, emmer, or wheat. Corn. Wheat, winter or spring. 

 Seeded to brome-grass. Brome-grass meadow. Brome-grass meadow. 



It is assumed that the corn crop will produce enough in the 

 form of fodder and grain to at least pay for the labor involved in 

 its production. The labor involved in raising a crop of corn is no 

 greater than that required to summer till an equal area. In com- 

 paring the yields obtained from the small-grain crops in a rotation 

 containing summer tillage with one containing corn it has been 

 assumed that the yields from the summer-tillage rotation must be 

 enough in excess of those from the corn rotation to pay for the 

 summer-tillage. Or, to put it in another way, the corn crop must be 

 sufficient to equal in value the excess in yield of the two small-grain 

 crops in the summer-tilled over those in the corn rotation. What- 

 ever form of comparison is used it is assumed that the labor required 

 to produce a crop of corn is approximately the same as to summer 

 till. The corn crop pays for the work bestowed upon it, while the 



