Investigations at Peru, Nebraska. 



31 



root extent was even much greater. In regard to corn, height growth and 

 root depth were about equal. However, what the corn lacked in relative 

 depth was adequately compensated for by widely penetrating and exceed- 

 ingly well branched roots. A comparison of the seedling stages of wheat and 

 oats shows that the roots of the former spread more widely. At this stage 

 of development the wheat roots were lighter in color, tougher, and, although 

 abundantly supplied with root-hairs, they did not occur in such density as 

 on the oats. The surface roots of wheat, when compared with those of 

 oats and barley, are found to be both less numerous and extensive. Thus, 

 the ability of oats to more thoroughly exhaust the surface soil of water and 

 nutrients, a belief current among agriculturalists, may have some foundation 

 in fact. Root habit gives a clue to the cause of this phenomenon. 



Table 1 gives a summary of the development of the several crops at various 

 stages of growth and affords an easy basis for comparison. 



Table 1. — Development of crops at Peru, Nebraska, 1919. 



Crop. 



Age 

 of 

 plants. 



Aver- 

 age 



height. 



Stage of 

 development. 



Maxi- 

 mum 

 depth. 



Maximum 

 lateral 

 Bpread. 



Remarks. 





days. 



feet. 





feet. 



feet. 





Oats, University No. 21 . 



18 



0.2 



1 leaf 



0.7 



0.4 



3 or 4 roots. 



59 



1.1 





3.6 



1.0 



1 or 2 tillers. 





92 



3.0 





6.7 



1.4 



1 or 2 tillers headed. 



Oats, Swedish Select. . . . 



19 



0.2 



1 leaf 



0.8 



0.4 



3 or 4 roots. 





60 



1.0 





3.7 



0.8 



1 to 3 tillers. 





93 



3.0 





6.8 



1.3 



1 or 2 tillers headed. 





19 



0.3 



1 leaf 



0.7 



0.4 



4 or 5 roots. 





60 



0.8 



5 leaves 



4.5 



1.3 



1 to 3 tillers. 





95 



2.5 



Stiff -dough stage 



7.4 



1.2 



1 tiller headed. 



Wheat, Marquis 



20 



0.2 



Second leaf unfolding. 



0.9 



0.6 



3 to 5 roots. 





70 



1.7 



5 leaves, jointing 



5.8 



1.3 



1 to 3 tillers. 





93 



2.7 



Stiff -dough stage 



6.7 



1.3 



1 tiller headed. 



Barley, Manchuria 



20 



0.4 



Second leaf unfolding. 



1.2 



0.7 



5 to 7 roots. 



54 



0.9 





4.5 



1.3 



1 to 3 tillers. 





84 



2.3 





6.3 



1.3 



1 or 2 tillers headed. 



Corn, Iowa Silver Mine. 



36 



1.0 



7 or 8 leaves 



1.3 



2.6 



12 to 15 roots. 





57 



4.0 





4.7 



4.0 



Plants growing vigor- 















ously. 





116 



8.5 





8.2 



4.0 



Greater part of leaves 















green. 



Potatoes, Early Ohio. . . 



56 



0.9 



Tubers appearing 



1.5 



2.2 



As many as 55 roots. 



94 



2.3 



One-third leaves dead. 



4.7 



2.1 



Roots variable in num- 















ber and extent. 



Some preliminary examinations were made of the development of roots 

 and above-ground parts of crop plants when grown as isolated individuals. 

 In general, both were found, in every case, to be more extensive than where 

 the crops were grown under the competition of normal field conditions (cf. 

 Weaver, 1920). 



