Journal of Agricultural Research 
Vol. XIV, No. 4 
168 
From Table IV it will be observed that the iron-ratio ranges for the 
cultures giving high or low yields of roots vary as markedly and in the 
same manner with the two different developmental growth periods 
(series A and B) as they do for the corresponding yields of tops. Thus, 
the cultures giving high root yields in series A show a wide range (8.97) in 
the magnesium to calcium ratio values and low ranges (3.48 and 1.32, 
respectively) in the values of the magnesium to potassium and calcium to 
potassium ratios, while the cultures of series B giving corresponding 
yields possess low ranges (2.32 and 2.55, respectively) for the magne¬ 
sium to calcium and the magnesium to potassium ratio values, and a wide 
range (5.40) in the values of the calcium to potassium ratio. The group 
of cultures which produced low root yields in series A shows a low range 
(2.16) of values for the magnesium to calcium ratio, an intermediate 
range (6.77) for the magnesium to potassium ratio, and a wide range 
(5.67) for the calcium to potassium ratio. In series B the group of cul¬ 
tures giving low yields of roots is characterized by wide ranges in the 
values of all three ratios. These values are 14.44, 10.70, and 4.22, for 
the ratios magnesium to calcium, magnesium to potassium, and calcium 
to potassium, respectively. 
A comparison of the data in Table III with those in Table IV brings 
out the fact that nearly all the ratio ranges for the cultures producing 
either high or low yields of tops show substantial agreements with the 
corresponding ranges for the cultures in the same series giving high or 
low root yields. It thus appears that the relation of high or low root 
yields to the proportions of the chemical ions is, in a general way, sim¬ 
ilar to the relation of the high and low yields of tops to these ion-ratio 
values. This follows, of course, from the general similarity of the posi¬ 
tions and ranges of the areas of high and low yields on the corresponding 
triangular diagrams of figures 1 and 2. Since in the same series the 
maximum yields of tops and of roots occurred with the same culture, 
as did also the minimum yield of tops and of roots, there is but one set 
of ratio values for the two kinds of maximum yields and one set for the 
two kinds of minimum yields for each of the two series. 
(3) DRY WEIGHTS OE SEEDS 
The absolute and relative dry weights of seeds obtained from the cul¬ 
tures of series B are presented in Table I, in connection with the corres¬ 
ponding data for tops and for roots. The absolute dry weight values 
represent, in each case, the averages from two series. The relative values 
were obtained, as were also the relative yields of tops and of roots, by 
dividing the average absolute dry weight value for each culture by the 
corresponding value for culture R1C1. The ratios of top yields to the 
yields of seeds are given in the last column of Table I. These ratio values 
represent the yields of tops expressed in terms of the corresponding 
yields of seeds considered as unity. 
