MAIZE OR INDIAN CORN 151 



germ chit or near the crown of the kernel. These tem- 

 porary roots die as soon as the primary roots begin to 

 develop. 



The primary roots. — The primary or permanent roots 

 spring -from the node of the underground stem, usually 

 about one inch below the surface of the soil. The depth 

 at which these roots originate and develop is, as a rule, 

 independent of the depth of planting, although the' Kansas 

 Station has showed that "the roots of hsted corn lia uni- 

 formly deeper in the soil than the roots of surface planted 

 corn.'" The primary roots of corn grow very rapidly and 

 branch profusely. Growth takes place as a result of the 

 constant addition of new cells at the growing point, which 

 is located just back of the cap or tip. The result of this is 

 that the tip of the root is pushed through the soil. \ During 

 the early stages growth is largely in a longitudinal direc- 

 tion. When the root growth has extended to a distance of 

 from 12 to 20 inches from the base of the plant, a portion 

 of the roots tiu^n abruptly downward, presumably to better 

 enable the plant to secure water. In time these roots may 

 grow to a depth of 3 or 4 feet. Lateral growth also con- 

 tinues until the entire upper 3 to 6 inches of the soil be- 

 tween the corn rows is completely filled with a mass of 

 much branched, fibrous feeding roots. Under favorable 

 conditions the lateral spread of corn roots is very rapid. 

 Studies on root growth at the North Dakota Agricultural 

 Experiment Station revealed that within thirty days after 

 planting, corn roots from hills 3 feet apart had met midway 

 between the hills at a depth of about 4 inches from the 

 surface (Fig. 20). 



Observations at -the New York, Minnesota, Wisconsin 

 and Colorado Stations indicate that during the first ten 

 to twelve days corn roots will spread laterally in the soil 



