568 The Philippine Journal of Science 1920 
From the dry-weight data of both series I and series II it ap- 
pears that for a given total concentration these plants were not 
very sensitive to small differences in the salt proportions. A 
relatively large number of salt combinations in both series I and 
series IJ gave approximately equal growth, with apparently iden- 
tical conditions other than those in the nutrient solution. Thus 
in series I eleven other solutions gave at least nine-tenths as 
high dry yields of tops as did the best solution; and in series IT 
twelve other solutions gave at least nine-tenths of the yield of 
tops obtained in the best solution. The individual differences 
between the different plants in a culture is probably the greatest 
factor in determining just which set of a number of very favor- 
able sets of salt proportions will give the very highest yield. 
The relation between the cation-ratio values and the yields of 
wheat tops for series I and II are shown in Table 9. It will be 
seen that for low yields of tops the Mg/Ca-ratio values cover 
practically the whole range of these values for the entire series. 
There is thus no relation between the value of the Mg/Ca-ratio 
and the low yield of tops. The same thing is also true of the 
values of the Mg/K- and Ca/K-ratios, since all tested values of 
these ratios give low yields in some cultures. 
TABLE 9.—Cation-ratio values for solutions of series I and II; for the 
entire series, and for solutions giving high and low and highest and 
lowest top yields. 
Mg/Ca Me/K Ca/K. 
| Series Series Series sig Series ay to 
fe = es 
| Entire series: 
Mininia --.. 3 Fo pekere 0.21 0.21 0.14 0.14 0. 08 0. 08 
Maxima .2. 2) 18. 43 18.48 4.68 4.68 2. 68 2.68 
Range .. 2... 13, 22 18. 22 4.54 4.54 2. 60 2.60 
Low yields: 
ea ee 0. 54 0.21 0.14 0.14 0.08 0. 08 
“eee sn EE eb 18. 43 13. 43 4,68 4.68 2.27 2.68 
style SET EA fe ng Sas 12.89 13. 22 4.54 4.54 2.19 2.60 
High yields: 
ese psig COE 0.58 0. 58 0.14 0.14 0. 08 0.08 
WRENS Oe 3.52 1.78 0.98 0.70 0.78 0. 45 
RANG 2.99 1.20 0.79 0.66 0.65 0.87 
Highest yidiis.. 8 1.72 1.72 0.40 0.29 0. 23 0.17 
Lowent yiele 5522 13. 43 13. 43 4.68} . 4.68 0.35 0. 85 
DO es ee 11:85 bee $61 | cece 0.28 
For high yields of tops, however, there does appear to be a 
certain relation between cation-ratio values and yield. High 
