668 SOILS: PROPERTIES AND MANAGEMENT 



no overhang, found on what is called the sod plow. This 

 neatly cuts off the roots at the bottom of the slice, slowly 

 and gradually twists the soil over without breaking the 

 sod, and lays it smoothly up to the previous furrow slice. 

 (2) The short, steep moldboard with a marked overhang. 

 This is not adapted to sod land, because it breaks up 

 the sod and shoots it over in a rough, jagged manner 

 with uneven turning. But on fallow land, to which it 

 is adapted, it very completely breaks up the soil and 

 throws it over in a nearly level, mellow mass. The pul- 

 verizing effect is obviously much greater than with the 

 sod plow. Since the steep moldboard, or fallow-ground, 

 plow exerts the most force on the soil in a given time at 

 a given speed of movement, it follows that if a particular 

 soil is over- wet it should be plowed with the sod plow; 

 while, if it must be plowed when too dry, the fallow-ground 

 plow will be more effective — disregarding the draft, 

 which will probably be larger in the latter case. 



573. Position of the furrow slice (Fig. 69). — Con- 

 siderable care should be taken concerning the angle at 

 which the furrow slice is placed. It is seldom desirable 

 to completely invert the soit. If it is too flat, the stubble 

 and rubbish are matted at the bottom of the furrow and 

 tend to interfere with capillary movement for a consid- 

 erable period. This may cause serious difficulty on 

 spring-plowed soil, where the capillary connection does 

 not have time to be renewed before a crop occupies the 

 land. If, on the other hand, the furrow is too steep, the 

 proper pulverization does not take place and the turning- 

 under of stubble and rubbish is not satisfactorily accom- 

 plished. The stubble and rubbish are likely to interfere 

 with subsequent operations. 7 



The best angle at which to turn the furrow slice is 



