242 Physics of the Soil. 



The extremely oblique construction of this plow too, 

 makes it easier to hold it steady when passing and cutting 

 off strong roots or other obstruction. 



FIG. 78. Type of pulverizing plow with steep molclboard. 



301, The Pulverizing or Stubble Plow It will be seen 

 from Fig. 78 that this plow has a much steeper mold board 

 and much less oblique plowshare, the object being to bend 

 the furrow slice as abruptly as possible before it is turned 

 over, for this is what pulverizes the soil, giving it the loose, 

 fine, open texture sought. 



302. Mellow Soil Plows. Soils which are sandy and 

 naturally very mellow rnay be plowed with a plow having 

 the mold board less steep and more like that of Fig. 79 in 

 shape. With such a form as this the team may cut a wider 

 furrow, and thus cover the ground more rapidly, because 

 the draft is less. 



When soils are very heavy and stiff it may also be de- 

 sirable to use this type of plow, simply because the draft 

 would be too heavy for the team with the type which pul- 

 verized the soil more. 



Again very loose soils which have an extremely fine tex- 

 ture and tend to clog will often clear better from the 

 less steep mold board because the pressure comes more 

 obliquely against the surface. 



