EXTENT OF THE ROOT SYSTEMS 85 
in many cases far beyond the belief of those who have 
given the subject little 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- 
