EXTENT OF THE ROOT SYSTEMS 85 



in many cases far beyond the belief of those who have 

 given the subject Httle or no attention. It may be 

 noted that on the basis of the figures above obtained, 

 it is very probable that the roots in one acre of an 

 average wheat crop would weigh in the neighbor- 

 hood of a thousand pounds — possibly consider- 

 ably more. It should be remembered that the 

 investigations which yielded the preceding results 

 were all conducted in humid climates and at a time 

 when the methods for the study of the root systems 

 were poorly developed. The data obtained, there- 

 fore, represent, in all probability, minimum results 

 which would be materially increased should the work 

 be repeated now. 



The relative weights of the roots and the stems and 

 the leaves do not alone show the large quantity 

 of roots ; the total lengths of the roots are even more 

 striking. The German investigator, Nobbe, in a 

 laborious experiment conducted about 1867, added 

 the lengths of all the fine roots from each of various 

 plants. He found that the total length of roots, that 

 is, the sum of the lengths of all the roots, of one wheat 

 plant was about 268 feet, and that the total length 

 of the roots of one plant of rye was about 385 feet. 

 King, of Wisconsin, estimates that in one of his ex- 

 periments, one corn plant produced in the upper 3 

 feet of soil 1452 feet of roots. These surprisingly 

 large numbers indicate with emphasis the thorough- 

 ness with which the roots invade the soil. Fig- 



