142 CROP ROTATIONS 



Similar annual rotations may be adopted for other cultivated 

 crops, such as corn, potatoes, sweet potatoes and market garden 

 crops. If the winter cover crop cannot be grown between the rows 

 of the main crop it may in some cases be started after the main 

 crop is removed. Such would be the case in the annual rotation 

 with spring wheat, spring oats, or other small grain. 



Two-year Rotations. Two market crops may be grown in 

 alternation with each other and frequent or constant use may be 

 made of cover crops. Under careful management winter wheat 

 may follow corn. When the wheat is harvested a cover crop is 

 grown until the next spring when corn is planted. A cover crop 

 may be composed wholly or in part of leguminous plants, and the 

 nitrogen supply will then be maintained. 



When cotton and tobacco are both grown one may follow the 

 other if a cover crop is used after each. 



Early potatoes and corn may be used in a two-year rotation 

 with a cover crop following each main crop. 



Three-year and Four-year Rotations. In systems of farming 

 where livestock are used and general farm crops are produced, 

 four-year rotations are commonly found. The four-year rotation 

 already described is a very common one. If more oats are pro- 

 duced by this method than are desired for the farm teams, Canada 

 field peas may be sown with the oats every other time the oats 

 are planted. The mixture of oats and Canada peas may be cut 

 for hay just at the close of the blossom period (Fig. 92). Some of 

 the oats and peas may be allowed to mature and then ground 

 together to be used as feed for dairy cattle, swine, poultry or other 

 livestock. This use of Canada peas with oats is a success in 

 northern and middle states but not far south. 



A good three -year rotation on a livestock farm may have 

 corn, followed by a cover crop, the first year; spring grain the 

 second year; clover which was seeded with the grain is cut for hay 

 the third year and the second growth of clover the third year is 

 used as green manure and turned under before corn is planted. 

 Thus two legumes may be used in the three-year rotation. 



This plan gives no timothy hay. but the rotation could easily 

 be extended one more year and if timothy seed is used with the 

 small grain, in addition to the clover, mixed hay is obtained the 

 third year and nearly clear timothy may be cut the fourth year. 



A good four-year rotation is illustrated in the main plots of 

 figure 93, a five-year rotation in figure 94, a seven-year rotation in 



