16, 5 Espino: Salt Requirements of Young Rice Plants 503 
average length of tops and of roots was obtained at the end of 
the culture period, for each culture of series 14 to 20. Discrep- 
ancies between the different trials of the same series, as to the 
relative physiological values of the various sets of salt propor- 
tions, are more pronounced in top length than in dry yield, and 
in root length than in top length, and the general consistency of 
the whole array of values for top and root length is of a low 
order. This may be considered as indicating that these length 
values are not as good criteria as are the dry yields, for bringing 
out differences in growth in the various cultures as here studied. 
It should be noted, however, that the method used in obtaining 
these approximate values involved considerable personal judg- 
ment and was not based on precision measurements and mathe- 
matical treatment. All things considered, it seems unnecessary 
to present all these length values here, although some samples 
for tops will be shown below. In spite of the discrepancies and 
inconsistencies of this mass of data, it generally appears that 
sets of salt proportions that appear most satisfactory by the 
criterion of dry yield also appear very satisfactory by the crite- 
rion of top length, and the solutions that appear to be badly 
balanced according to the one criterion also exhibit very poor 
growth according to the other. 
Table 10 shows the actual and relative top-length values for 
the three sets of salt proportions chosen as the most promising, 
and for the two sets chosen as least promising on the basis of 
dry yields. The relative value is placed in parenthesis after 
the actual value in each case. 
TABLE 10.—Approximate mean length of tops for selected solution of 4-salt 
solution type A. 
| 
cape ae decy ok e a ec 
pemnage 2a 
cm. em. cm. | em, | em, cm, cm. 
TIRIS1_____ 30.0(1.00) | 40.0(1.00) | 35.0(1.00) 38.5(1.00) | 36.0(1.00) | 38.4(1.00) | 31.3(1.00) 
TIRIS2_____| 29.5(0.98) | 38.3(0.96) | 34.4(0.97) | 39.0(1.01) | 35 0(0.97) | 30.0(0.90) | 27.7(0.89) 
TIRsGi.. 81.5(1.05) | $9.5(0.99) | 32.6(0.98) | 38.0(0,99) | 38.2(1.06) | 30.010. 90) | 29.0(0. 98) 
TSR1S3_____| 26.3(0.88) | 30.6(0.77) | 27.0(0.77) | | 26. 0(0.68) | 29.8(0.83) | 23.8(0.71) | 17.0(0.54) 
T4R1S2_____ 28.5(0.95) | 33.5(0. 84) | 26. 6(0. 76) | | 23, 0(0,60) | | 29.3(0.81) | 23.0(0.69) | (20. 3(0. 65) 
It is clear that the best three sets of salt proportions of Table 
‘ 10 agree in showing the two medium total concentrations as 
about alike and markedly better than either the lowest or the 
highest total concentration here considered, thus supporting the 
conclusion derived from the data of dry yield. This is not so 
clear for the two badly balanced sets of salt proportions in this 
171114——_5 
