32 FIELD AND LABOKATORY STUDIES OF CROPS 



young plant with moisture. During the early growth stage 



the young plant is nourished by the food which is stored up in 



the kernel, but by the time 

 the plants appear above the 

 ground a permanent root 

 system has begun to form 

 about an inch below the 

 surface of the ground. This 

 system grows very rapidly 

 at first and by the time the 

 plants are a month old the 

 roots will meet between 

 the rows. When the per- 

 manent roots are well 

 started, the temporary roots 

 wither and die, leaving the 

 plant to depend upon the 

 permanent system. Deep 

 planting of the seed does 

 not secure deep rooting 

 except for the temporary 

 system, and in most sea- 

 sons is harmful rather than 

 helpful, since the deep 

 planting makes it more 

 difficult for the young 

 plant to get its leaves up 

 through the soil and into 



the air, from which it must obtain its supply of carbon 



for the formation of tissue. 



Fig. 12.— a Glass Case Used for 

 Observing the Early Growth and 

 Development of the Corn Plant. 



