PART V— CONCLUDING CHAPTERS 



CHAPTER XXVI 



ROTATION OF CROPS 



648. Definition. A rotation of crops, according to the 

 Cyclopedia of American Agriculture, is ''a recurring succes- 

 sion of plants covering a regular period of years and main- 

 tained on alternating fields on the farm." Crop rotation 

 can best be explained, perhaps, by giving an example of it 

 which is common in many sections. A cultivated crop, as 

 corn or potatoes, is grown on one part of the farm the first 

 year; a grain crop, as wheat, oats, or barley, on another; 

 and a grass crop, as timothy, clover, or brome grass, on a 

 third part. The following year the grain will occupy the 

 land where the cultivated crop was grown; the grass crop, 

 which was sown with the grain the first year, will occupy that 

 land; while the land in grass the first year will be broken and 

 planted to a cultivated crop. This regular sequence of 

 cultivated crops, grain crops, and grass crops, is called a 

 rotation of crops. Unless there is some definite plan and 

 reason for such a sequence, it cannot properly be called a 

 rotation. For instance, the alternating of oats or barley or 

 flax with wheat in a spring-wheat region can hardly be called 

 a rotation, for it does not conform to the principles on which 

 crop rotation is ])ased. 



649. Origm of Crop Rotation. The system of farming 

 which was originally followed was to grow a crop on a piece 

 of land continuously until the yields decreased below the 

 point where production was profitable. Then the land was 

 allowed to ''rest"; that is, it reverted to a state of nature, 

 growing up to weeds, brush, or trees, while a new field was 



