68 AGRICULTURE. 



water to percolate through the soil instead of 

 running off of the surface. Plowing should 

 never be done when the soil is wet enough to 

 puddle.* 



A soil which is loose and open, or one having 

 a sandy subsoil, does not require such deep 

 plowing as a more compact soil. If the soil is 

 wet and not underdrained, plowing may only 

 increase the supply of ground water. If it is 

 desired to deepen a soil, it is best to plow a little 

 deeper each time, so that the portion of subsoil 

 brought to the surface will not be sufficient to 

 materially injure the character of the soil for the 

 immediate crop. A small amount can be more 

 readily acted upon by the weathering agencies 

 than a greater amount can be. 



Plowing at different depths prevents the 

 formation of a hard-pan by the tramping of the 

 horses at the same depth in successive plow- 

 ings. On the other hand, if the soil is very 

 porous, it may be prevented from leaching by 

 plowing at the same depth to form this hard- 

 pan, thus keeping the free, or ground water, 

 within the reach of plants. If deep-feeding 

 plants as, alfalfa, clover, or vetch are to oc- 

 cupy the land, it should be deeply plowed, and 

 thoroughly pulverized. 



In early spring shallow plowing is usually 

 preferable, as the deeper soil is not so warm 



*See " Propagation." 



