SOME CONDITIONS INFLUENCING GROWTH II 



are, their character, and requirements. Examination 

 of the roots of Early Ohio potatoes, 1 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 eyes on the upper side of each tuber produced shoots; 

 thus one hill produced three stalks from two eyes, 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 direction. 

 The roots from each hill had already 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 



i N. Dak. Bui. 45, p. 541. 



