16, 5 
Espino: Salt Requirements of Young Rice Plants 489 
here made may be interpreted in any great degree of detail. 
Until such controls (especially of air and light conditions) 
become available, all that can be done is to make the survey 
for such problems as this rather superficial, to discuss the more- 
and the less-promising solutions for the uncertain range in the 
complex of non-solution conditions with which the whole inves- 
tigation deals. This will be attempted in the present case, and 
the generalizations that are presented below are to be regarded 
as only tentatively established ; they are meant to apply to such 
non-solution conditional complexes as were met with in the 
greenhouse here used, between May 1 and July 9. 
It is seen from Table 5 that no set of salt proportions falls 
in the high group (H) for all series and that only two sets 
(T3R1S3 and T4R1S2) fall in the low group (L) for all series. 
Furthermore, no set of proportions falls in the medium group 
(unmarked in the table) for all series. Inspection of the actual 
top yields (from which the relative values of Table 5 have been 
computed) leads to the conclusion that the solutions of series 
14 (the lowest total concentration dealt with) are in general 
too dilute to give the best growth of these plantlets, and, sim- 
ilarly, that those of series 20 (the highest total concentration 
studied) are too concentrated. This statement is supported by 
the data of Table 6, which shows the ranges of the actual top- 
yield values for the high and low groups, for the four series 
carried out simultaneously beginning June 19. A similar sum- 
mary of the ranges for root-yield values is given in the same 
table. 
Table 6. — Highest and lowest yields of tops and of roots {milligrams) in 
the high and in the low groups for the four series carried otit simul- 
taneously beginning June 19. 
Series 14 (low- 
est total concen- 
tration). 
Series 16 (low- 
medium total 
concentration). 
Series 19 (high- 
medium total 
concentration). 
Series 20 (high- 
est total con- 
centration). 
Highest. 
Lowest. 
Highest. 
Lowest. 
Highest. 
Lowest. 
Highest. 
Lowest. 
Tops--- 
High group-- 
240 
214 
287 
235 
263 
224 
236 
185 
Do... 
Low group.— 
184 
154 
192 
163 
176 
115 
138 
80 
Roots— 
High group.. 
86 
72 
78 
72 
74 
64 
82 
50 
Do— 
Low group... 
65 
64 
62 
62 
53 
42 
45 
36 
From the upper part of Table 6 it appears that the maximum 
top yields from series 14 and 20 are both lower than either of 
the corresponding maxima for the two remaining series, and 
that the minimum top yields for the high group for series 14 
