108 



DRY FARMING 



turning their vegetative parts under the furrow slice. 

 The roots are cut by the sharp share and the vegetation 

 is turned under by the upward sloping, outward curv- 



37a. The Disc Plow. 



ing mouldboard (Fig 37). The covering is facilitated 

 by having a straight-edged furrow which the coulter 

 (Fig. 37 C) makes. The effectiveness of the covering may 

 be increased by the jointer or skim coulter, or by drag 

 chains. The surface litter, of whatever form, is disposed 

 of by thorough covering. 



The soil is pulverized least by a long sloping mould- 

 board (breaker bottom) and most by an abrupt mould- 

 board (stubble bottom). The former is used in sod 

 plowing because it turns a sod furrow better and the 

 draft is lighter. The latter is used in stubble land be- 

 cause it turns the stubble furrow better and pulverizes 

 more. (Fig. 37.). 



When it is desired to loosen up heavy subsoil deep 

 plowing may be practised or a subsoil plow or subsoil 

 attachment (Fig. 37B) may follow in the furrow of the 

 ordinary plow. 



Kinds of Plows. There are mouldboard and disc 

 plows; and among the mouldboard types there are sod 



