556 Journal of Agricultural Research voi.xxi.No.s 
PLANTS GROWN WITH THEIR ROOTS EQUAI^Y DIVIDED AMONG THREE 
♦ SOLUTIONS 
It was of interest to see whether there would be a greater depression 
in growth and assimilation when the roots were divided among three 
solutions than when the roots were divided between two solutions. 
Experiment V.—The roots divided among three solutions, each of 
which lacked one element. 
In this experiment the roots were equally divided among three solutions 
which were lacking in nitrogen, phosphorus, and potassium, respectively. 
The data on growth and assimilation are given in Tables VIII and IX. 
A division of the roots among three solutions, each of which lacked 
one element, depressed the growth by 13 per cent, and the mean assimi¬ 
lation of nitrogen, phosphorus, and potassium, by 32 per cent. In 
experiment III, where the roots were divided between two solutions, 
each also lacking in one element, the average depression in growth was 
30 per cent and the average depression in the mean assimilation of nitro¬ 
gen, phosphorus, and potassium, was 42 per pent. The plants in ex¬ 
periment V may have had somewhat of an advantage over those in 
experiment III, since any one of the three elements was available to 
two-thirds of the roots in this experiment, while in experiment III two 
of the three elements were each available to only one-half of the roots. 
The greatest growth of roots was made in the solution containing 
nitrogen and phosphorus (C flask), and the least growth took place in 
the solution containing phosphorus and potassium. These growths 
agree with the results shown in experiments III and IV. 
It is interesting to note that the roots which were in the solution con¬ 
taining nitrogen and phosphorus were considerabty richer in nitrogen 
than those which were in the solution containing nitrogen and potassium; 
also, the roots which were in the solution containing nitrogen and potas¬ 
sium were slightly richer in potassium than the roots which were in the 
solution containing phosphorus and potassium. These facts appear to 
confirm the results of the former experiments in showing that the need 
of the plants for nitrogen, phosphorus, and potassium is in the order 
given; and they also seem to indicate that the assimilation of one element 
from a solution facilitates the assimilation of another element from that 
solution. The roots in C flask, for example, were richer in nitrogen than 
those in B flask, because phosphorus is needed more than potassium, 
and on this account the assimilatipn of phosphorus aided the assimilation 
of nitrogen more than did the assimilation of potassium. 1 
Experiment VI.—The roots divided among three solutions, one of 
which lacked two elements and two of which each lacked one element. 
1 In this explanation it is assumed that a higher percentage of an element in the root at the time of analysis 
means a more active assimilation of this element by the root. 
