16,6 Espino: Salt Requirements of Young Rice Plants 519 
well balanced as is AT1R2S1. The last-named solution is un- 
doubtedly the most promising of the present series, and it is the 
only one of the three previously selected as representing good 
physiological balance, that was included in the present series. 
The data of Table 15 therefore support the conclusion reached 
from the more thorough study of type A; namely, that TIRISI, 
T1R2S1, and T2R1S1 are to be regarded as about equal and as 
very well balanced for these plants. This conclusion is especially 
strengthened by the fact that the solutions tested in the present 
series were selected because they showed high values in earlier 
tests, but before the analysis by agreements and disagreements 
had been completed. It is unfortunate that solutions ATIRISI 
and AT1R1S2 were not included in the final series. 
It is of interest to emphasize that solution type B is shown 
to be capable of giving yield values of the best group, in spite 
of the fact that these solutions always produced marked leaf 
injury. 
With regard to the 3-salt solutions of the final series. Table 
15 shows that the representative of this type gave entire plant 
yields of 0.62 or below, and top yields of 0.47 or below, while 
their root yields approach very nearly to being included in the 
best group, their values being from 0.87 to 0.94. It may be 
suggested that the best sets of salt proportions of the 3-salt 
type I series of solutions, with the two low total concentrations 
as well as with the single higher one found to be nearly optimal 
for wheat plantlets (Shive), are very well balanced for the 
production of dry root yields, although they are very badly 
balanced a.ccording to the criteria of top yields or entire plants. 
This suggestion may possibly be of importance at some later 
time when the relations between the physiology of roots and that 
of tops is better understood and attracts more attention than is 
now the case. 
It is obvious enough from Table 15 that none of these best 
3-salt solutions is at all well suited for young rice plants ; they 
all belong in the poor group of this series, on the basis of yields 
both of tops and of whole plants. This result of the final series 
supports that reached on the basis of appearance of the plants, 
as stated in an earlier section of this paper. 
The last two solutions shown in Table 15 deserve special 
attention. These have the salt proportions of Shive’s best so- 
lution for young wheat plants (IR5S2) ; they are based on the 
scheme of osmotic (instead of molecular) proportions and on 
the triangular diagram with increments of one-tenth (instead of 
171114 6 
