484 
Philippine Journal of Science 
1920 
among which the different plant forms will be found to be dis- 
tributed, It should be emphasized that the data for the four 
plants thus far studied indicate no solution as well balanced for 
all, although those with lowest partial concentrations of both 
monopotassium phosphate and calcium nitrate should be well 
balanced for both soy bean and rice. 
Aside from the question of salt proportions, it is to be noted 
that Shive’s best solutions for wheat and buckwheat have osmotic 
values of 1.75 atmospheres, and that the best solution he records 
for soy bean has an osmotic value of 2.5 atmospheres ; while the 
best total concentration for rice, with this type of solution, 
proved to be about 0.2 atmosphere. In connection with all these 
considerations it is to be remembered that none of these 3-salt 
solutions gave really good growth to the young rice plants ; what 
is termed “good” on the lowest diagram of fig. 3 is only relatively 
good — ^that is, the best obtained with this solution type. It is 
thus suggested that the best solution for these rice plants will 
be found to have a very low total concentration, as compared 
with the best solutions for wheat, buckwheat, and soy bean. 
This is borne out by the findings to be reported in the following 
sections of this paper. 
It seems, therefore, that the total concentration best suited 
to the growth of a given plant is determined not only by the 
salts and salt proportions but also by the kind of plant con- 
sidered; also probably by the developmental stage of the plant 
and by the non-solution conditions of the environment. Dif- 
ferent plant forms show different requirements with respect to 
the total concentration as well as with regard to salt proportions. 
The general appearance of the rice plantlets after growing 
three weeks in the best of these 3-salt solutions is shown by the 
photograph, Plate 1, fig. 6. 
four-salt type a (monopotassium phosphate, calcium nitrate, magne- 
sium SULPHATE, AMMONIUM SULPHATE) 
Introductory . — The results obtained with the four-salt solu- 
tion type A refer to nine different experimental series (series 
14 to 22 inclusive, see Table 3) and to six different total concen- 
trations. The numerical results will be presented after values, 
but the general appearance of the plants has been considered. 
General appearance . — After five or six days in the culture 
A single set of salt proportions of this type of solution was used by 
Wolkoff; see Wolkoif, M. I., Effect of ammonium sulphate in nutrient solu- 
tion on the growth of soy beans in sand cultures, Soil Sci. 5 (1918) 123-150. 
