SOME CONDITIONS INFLUENCING GROWTH II 



are, their charadler, and requirements. Examination 

 of the roots of Early Ohio potatoes,' made July 5, 1899, 

 forty-three days after planting, about the time the crop 

 received its third cultivation, showed that at this time 

 there was little growth of fibrous roots — only the skele- 

 ton system supplied with numerous delicate root hairs. 

 The seed tuber appeared to be sound and whole, but on 

 closer examination it proved to be but a shell. Only a 

 few ej'es on the upper side of each tuber produced shoots; 

 thus one hill produced three stalks from two e5-es, and 

 another had seven stalks springing from five eyes. 

 The latter plant had more numerous but smaller roots 

 than the former. Twenty-five small potatoes were set 

 on the first plant, the largest of which were the size 

 of a large pea. At this stage of development the main 

 portion of the roots was in the surface eight inches, a 

 few roots reached to the depth of eighteen inches, but 

 the greatest root growth was in a horizontal diredlion. 

 The roots from each hill had alread)' met and interlaced, 

 some having reached a length of two feet, the plants 

 being three feet apart. At six inches from the hill some 

 of the main lateral roots were but two and one-quarter 

 inches from the surface of the ground, while midway 

 between the rows their depth was barely three inches 

 from the surface. 



Further examination of Early Ohio potatoes seventy- 

 two days after planting, when the tubers were nearly 

 full size, showed that the main root growth was in the 

 upper foot of soil ; several of the large horizontal roots 

 were within three inches of the surface, and one was 

 but one inch deep. Some of the vertical roots reached 



> N. Dak. Bu!. 45, p. 541. 



