Investigations at All Stations. 



air-dried the vegetation yielded an average of 196 grams per square meter 

 at Burlington, 306 at Phillipsburg, and 444 at Lincoln. Wheat-grass, during 

 1921, gave an average yield per square meter of 400, 457, and 606 grams respec- 

 tively. These data are typical of those obtained during a series of years 

 (Weaver, 1921). 



Similar relations hold as regards the extent of the roots of native vegetation. 

 The roots of seedling grasses and certain subdominant herbs penetrate the 



Idly and to a greater depth than at Lincoln, 

 3st root-growth was recorded. Similarly, 

 ivere found to penetrate from 2 to 4 feet 

 or Phillipsburg. Regarding the normal 



i several plant associations, the following 



the grass i an( i formation" are instructive. 



~ s of eastern Nebraska, 14 per cent had roots 



m g 3 first 2 feet of soil; 21 per cent were rooted 



* >w 5 feet; while 65 per cent penetrated to 



tetimes to 12 or even 20 feet, 

 nixed prairie (hard lands), 11 per cent were 

 I S ent were of intermediate depth (2 to 5 feet) , 



I f; extended well below the fifth foot of soil, 



I ™ jet. Of these, 71 per cent are well adapted 



t, g t-face soil only is moist. 



00 ies of the short-grass plains, all but one are 



1 he surface soil. Three are shallow rooted, 

 g nd their roots beyond a depth of 5 feet. 



g lepth as one goes eastward from the short- 



£ the deep subsoil is constantly moist is in 



m na de on the root depth of cereals at 14 



® it extent in the true prairie as unity, the 



m short-grass plains was as follows : Working 



5 100 : 95 : 79; winter wheat, 100 : 93 : 61. 



| 50 :65; oats, 100 :94 :77; winter wheat 

 «— 



rect correlation may be seen between the 

 5 of crops and that of the native vegetation 

 onment. 



