SOME CONDITIONS INFLUENCING GROWTH 15 



A sample of Early Ohio potatoes taken ninety days 

 after planting, when the vines were beginning to die 

 and the tubers were nearly ripe, showed that the roots 

 penetrated to a depth of over two and a half feet. 1 The 

 branches from the main lateral roots had reached about 

 as deep as those immediately under the hill, and the 

 soil was filled with roots to a depth of about two and 

 a half feet. The system of rooting is similar to that of 

 corn, but the plant is not so good a forager, and the 

 roots do not fill the soil so completely; hence, plants 

 can be placed closer together. 



Late ^varieties have a similar root system, but root 

 more freely, more deeply (a depth of three and a half 

 feet being common if the soil conditions will permit), 

 and occupy the ground more completely; hence, require 

 mofe room than early varieties. 



At Cornell University, during 1904, many potatoes 

 had horizontal roots in the surface inch of soil. All 

 of these would be destroyed by moderately deep tillage. 



Influence of Depth of Planting on Roots. 

 Generally speaking, the new potatoes and the roots start 

 out above the seed, although if an under eye of the 

 potato produces the shoot the roots and tubers may 

 develop at the side of the seed. Depth of planting has 

 some influence on the depth at which the tubers will 

 form, and may have some on the roots. The question 

 deserves investigation. Many plants prefer to send 

 out their roots at a uniform depth below the surface : 

 thus, at Cornell University, wheat, whether planted 

 six inches deep or one inch deep, will send out its per- 



N. Dak. Bui. 43, p. 544. 



