CULTIVATION AND GROWTH 25 



necessary, and the plowman is impatient to have 

 the field cleared of the previous crop so that he 

 may do his work early. Careful studies seem to 

 show that early plowing is favorable to the best 

 yield for the succeeding year. It conserves mois- 

 ture and provides a better packed seed bed. 



FIG. 14. The disc plow. Instead of moldboards and lays, large discs are used 

 to cut and turn the soil. Some farmers prefer this kind. 



In spring wheat districts, the ground is usually 

 plowed in the fall because the wheat needs to be 

 sown as early in the spring as possible. This is 

 particularly true where the growing season is 

 short as in Minnesota or the Dakotas. There 

 the seeding is done as soon as the ground is free 

 from frost. The soil is well ventilated by the 



