10 



Development and Activities of Roots of Crop Plants. 



others as far as 1.4 feet from the base of the plant. Thus, the spread of these 

 shallow roots had increased 4 or 5 inches since May 29. These horizontal 

 roots often continued their course near the surface of the soil. Frequently, 

 throughout their whole length, no portion of them could be found that was 

 deeper than 1.5 to 3 inches. Other roots extended almost parallel with the 

 surface for a distance and then turned downward, ultimately reaching depths 

 of 1 to 5 feet. Still others descended almost vertically until they reached 

 depths of 5 to 5.5 feet or more, the maximum length found being 6.7 feet 



Fig. 1. — A. Root system of University No. 21 oats 59 days old. 

 B. Swedish Select oats 60 days old. 



(fig. 2 a). 5 to 7 of these deeper roots were commonly found. This is an 

 increase of 4 or 5 over those present at the time of the preceding examination. 

 The roots were all profusely branched with fine branches ranging from 0.1 to 

 4 inches in length. This was especially true of those lying near the surface, 

 where the branches were longest. On practically all of the roots at this 

 time the branches extended almost to the tips. The roots were very fragile, 

 especially the deeper ones. The shrunken and shriveled cortex indicated 

 that considerable material had been transported from them. The soil was 

 fairly well filled with roots to a depth of 3.8 feet, and below this to 5.4 feet 

 they were quite numerous. Thus, it is evident that the root system of this 



