16.6 Espino: Salt Requirements of Young Rice Plants 515 
occurs it is between two contiguous groups, H and M, or M and 
L. These considerations constitute still further evidence in favor 
of the conclusion that all these plant criteria are about the same 
in their indications as to the relative physiological values of the 
various sets of salt proportions. 
As in previous cases, it is instructive to place the water-absorp- 
tion designations for the two medium total concentrations on 
the tetrahedral diagram and then indicate the regions of high 
and low values. Such a diagram is shown in fig, 9, which 
is markedly like the diagrams, figs. 4 to 8. The experi- 
KHj PO4 
Fig. 9. Distribution of low, medium and high water-absorption values for series 16 and 19. 
