HANDLING THE SOIL 



37 



and one can plow backward and forward along the side of 

 the hill. This is called a swivel-plow. There is a kind of 

 plow which has a concave disk in place of the share and 

 mold-board. This is called a disk-plow. It does good work 

 in stubble ground, free from sticks and stones. It has not 

 come into use very much yet. A subsoil plow is one that can 

 be run in the furrow made by the ordinary plow and stir up 



A SUBSOIL PLOW 



the subsoil. It has a longer shank than other plows and 

 usually does not turn a furrow-slice, but shoves through the 

 ground like a ground-mole, loosening the soil. 



Plowing. — Plowing is the most important tillage operation. 

 Its main purpose is to pulverize the soil. When the soil slips 

 up over the mold-board the particles are made to slip over 

 each other and so tear it apart, making it loose. When the 

 ground is in just the right condition to plow, the furrow-slice 

 will be turned over with scarcely any clods and a very small 

 amount of harrowing will put the soil in good condition for seed. 



