EXERCISE 38 (Continued) 



Part III. To Criticise a Rotation. The following are eight requirements 

 of a good rotation. State opposite each requirement how your rotation meets it. 



1. Plant Food. The crops in a rota- 



tion should have different plant 

 food requirements. 



2. Roots. A rotation should include 



deep rooted and shallow rooted 

 crops. The roots of certain crops 

 such as grass, millet, buckwheat 

 and barley, have a beneficial 

 effect on the structure, espe- 

 cially of heavy soils. 



3. Organic Matter. Sods, stubbles, 



or green manure crops should be 

 plowed under; or all of these. 



4. Legumes. Nitrogen from the air 



is obtained by these plants. A 

 rotation should include one or 

 more of them. 



5. Weeds. Rotation should control 



weeds usually by means of cul- 

 tivated crops. 



6. Unoccupied Land. The ground 



should not be left bare during 

 part of the year so that the 

 soil may wash or the weeds get 

 a foothold. 



7. Diseases and Insects. A rotation 



should be able or adjustable to 

 control diseases, as potato scab, 

 which live over in the soil and 

 insects like i tfi4 wireworm, which 

 thrives in sod left down too long. 



8. Labor Distribution. A good rota- 



tion should distribute work 

 as evenly as possible through 

 the season. 

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