204 POWER AND THE PLOW 



Deep plowing, on the contrary, throws up heavier and rougher 

 furrows, and tends to anchor the soil in place. Plowing deep, 

 therefore, prevents both washing and drifting." 



In many dry-farming sections the rainfall is so light that 

 summer fallowing must be resorted to. This consists of 

 cultivating an empty field during one entire season to prevent 

 plant growth and conserve the rains of that year for the use 

 of the next year's crops. It is seldom necessary to provide as 

 great storage capacity as is given by the expensive method of 

 subsoiling, but plowing ten or twelve inches deep with ordinary 

 plows places the moisture reservoir at a safe depth and makes 

 summer fallowing a less expensive means of insuring a crop. 



Deep plowing cannot be accomplished a^ljU^jmce_^n_ any 

 new soil. Where the soil is heavy and compact, the prame 

 is~apt to be covered with "short-grass" sod, indicating that 

 only an inch or two of the surface is hi condition to sustain 

 plant growth. The soil underneath is apt to be cold and 

 unproductive, hence must be mixed slowly with the upper 

 layers and put into proper physical condition by good tillage 

 and exposure to the sun and air. Fall plowing can be done 

 more deeply on this account than spring plowing, owing to the 

 weathering action of frost and snow. For a year or two after 

 the ground is first broken the plowing should not be at the same 

 depth as the first breaking, as this will expose undecomposed 

 vegetation, the lack of moisture in dry climates retarding decay. 

 The ultimate depth desired should be attained gradually, and 

 afterward the depth should be varied from year to year to 

 avoid forming the "share hardpan." This is a hard, glazed 

 condition of the sole of the furrow which renders it impervious 

 to water. The trowel-like effect of the share and the tramping 

 of the furrow horse's feet bring it about. 



A firm seedbed is especially important in dry-land agricul- 

 ture to insure prompt germination. In deeply plowed land it 

 is therefore advisable to use a subsurface packer. This re- 

 packs the intermediate layers, but leaves the top and lower soil 



