THE PROBLEM OF TILLAGE 



be used for breaking the prairie. But 

 disc plows are now widely used and have 

 a recognized place on the dry-farm. 

 They do good work in old lands, the 

 draft is lighter, and they can be used in 

 drier soil than is practicable with the 

 moldboard. A disc plow, if run deep, 

 is of special value in breaking up the 

 plow-sole which is apt to be formed by 

 the too constant use of the moldboard 

 plow set at the same depth year after 

 year. Many farmers, however, try to cut 

 too wide a furrow with their disc plow, 

 which results in a poor job. Gang plows 

 save much time and labor and enable one 

 man to keep several horses at work. Rod- 

 breaker plows in which steel rods take 

 the place of the solid moldboard have 

 been found useful in tiu-ning over virgin 

 land. Subsoil plows are intended to 

 loosen and pulverize the subsoil without 

 inverting it or bringing it to the surface. 

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