PLOWS FOR DRY-FARMING ; 305 
plow, characterized by a long sloping moldboard, is 
the best known implement for breaking all kinds of 
sod. (See Fig. 75a.) Where the sod is very light, as 
on the far western prairies, the more ordinary forms 
of plows may be used. In still other sections, the 
dry-farm land is covered with’ a scattered growth of 
trees, frequently pinion pine and cedars, and in Ari- 
zona and New Mexico the mesquite tree and cacti are~ 
to be removed. Such clearing has to be done in ac- 
cordance with the special needs of the locality. 
Plowing 
Plowing, or the turning over of the soil to a depth . 
of from seven to ten inches for every crop, is a funda- 
mental operation of dry-farming. The plow, there- 
Fic. 73. Parts of modern plow. 
fore, becomes one of the most important implements 
on the dry-farm. Though the plow as an agricul- 
tural implement is of great antiquity, it is only within 
the last one hundred years that it has attained its 
present perfection. It is a question even to-day, in | 
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