ROTATION OF CROPS 177 



CHAPTER XX X I L— Rotation of Crops 



166. What is Meant by Rotation. — Rotation meana 

 changing annually the kind of crop grown upon a 

 ghwn soil, the change being usually made in a regular 

 order. For instance, from a certain field a crop of 

 tobacco is grown; the next season the same field is 

 planted in wheat, and the next in clover; the year after 

 the clover, tobacco may be again grown, then wheat, 

 and after the wheat clover again. Thus a rotation of 

 these crops is practiced, but four or even more crops 

 may be used in a rotation. In general farming rota- 

 tion is much practiced, but in special farming it is 

 unfortunately seldom m 



167. Benefits of Eotation. — Rotation of crops when 

 properly practiced may be of benefit to the soil in 

 many ways: 



1. The way in which soils are cultivated varies with 

 different crops. Tobacco and cotton for instance leave 

 the soil quite bare; wheat and oats leave a thick stubble 

 and large crops of weeds spring up as soon as they are 

 gathered. If tobacco or cotton be grown continuously 

 on one field, the soil suffers from washing and leach- 

 ing. Tobacco and cotton should be rotated with crops 

 that protect the soil, such as wheat and oats. 



2. Many crops have shallow roots which draw most 

 of their food from the Dppei soil. If such crops are 

 grown continuously on a field, the upper soil becomes 

 exhausted while the lower soil is untouched. Crops 



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