502 
Philippine Journal of Science 
1920 
With reference to what sets of molecular salt proportions 
constitute bad physiological balance for these plants, it has 
been mentioned that, in general, progressively higher relative 
partial concentrations of monopotassium phosphate give progres- 
sively poorer yields. At the same time it is to be noted that 
bad physiological balance generally accompanies low relative par- 
tial concentrations of magnesium sulphate. Perhaps the worst 
solution of this 4-salt type may, as here tested, be represented 
by T3R1S3 or by T4R1S2. These have the molecular salt pro- 
portions shown below: 
Solution No. 
KH 2 PO 4 . 
(NH4)2S04. 
Ca(N03)2. 
MgS04. 
T3R1S3 
3 
1 
3 
1 
T4R1S2 
4 
2 
1 
They are characterized by high relative proportions of mono- 
potassium phosphate and calcium nitrate, and by low proportions 
of ammonium sulphate and magnesium sulphate. But the best 
solutions for top and root yields are also characterized by low 
relative proportions of the ammonium salt, as has been seen, so 
that the distinguishing characters of these very poorly balanced 
solutions are high proportions of monopotassium phosphate and 
calcium nitrate and low proportions of magnesium sulphate. 
From the nature of the results that have been presented and 
from the nature of the problem itself, it is undesirable to attempt 
to fix upon any one of the sets of salt proportions as most poorly 
balanced ; to attempt this would lead to discussion of the general 
problem of toxicity and starvation. 
Referring to the studies of earlier students of rice culture 
and of the salt nutrition of the rice plant, the conclusions just 
brought forth appear to substantiate the more general ones that 
have been expressed in the literature; namely, that young rice 
plants require ammonium and cannot thrive with nitrate as the 
only source of nitrogen, and that rice needs relatively little 
potassium and relatively much magnesium, while it cannot gen- 
erally bear much calcium. An additional point, not emphasized 
in the literature, is that the best growth of young rice is not to 
be expected with anything but comparatively low proportions 
of the ammonium salt, although the present studies suggest that 
ammonium sulphate is not so injurious in higher proportions 
as is monopotassium phosphate. Perhaps it may be said to be 
about as injurious as calcium nitrate. 
Lengths of tops and roots . — As has been said, the approximate 
