4i 6 Journal of Agricultural Research voi. vn, no. 9 
of carbohydrates, any salt such as sodium carbonate, which would 
interfere with the absorption of potash §it this stage of growth would 
seriously handicap the development of the plant. 
It will be recalled that calcium carbonate was present in the culture 
solutions in the solid phase. It will be shown in another paper that 
appreciable quantities of sodium carbonate are formed through the 
reaction of sodium chlorid and sodium sulphate with calcium carbonate, 
and the resulting hydrolysis is greater with sodium sulphate than with 
sodium chlorid. This is in harmony with the greater activity shown 
by sodium sulphate in depressing the absorption of potash and phos¬ 
phoric acid and suggests that the effect observed in the case of sodium 
chlorid and sodium sulphate may be in part due to the small amounts 
of sodium carbonate formed through reaction with the calcium carbonate. 
CONCLUSIONS 
Sodium chlorid, sodium sulphate, and sodium carbonate added to 
nutrient solutions in concentrations up to 1,000 p. p. m. do not measur¬ 
ably affect the nitrogen absorbed from culture solutions by young wheat 
plants. , 
Sodium chlorid in concentrations up to 1,000 p. p. m. does not affect 
the absorption of phosphoric acid, but decreases slightly the absorption 
of potash. 
Sodium sulphate in concentrations of 1,000 p. p. m. depresses the 
absorption of potash and phosphoric acid to approximately 70 per cent 
of that of the control cultures, expressed in percentage of dry weight of 
the plants. 
Sodium carbonate in concentrations of 1,000 p. p. m. reduces the 
absorption of potash to 20 per cent of that of the control and the absorp¬ 
tion of phosphoric acid to 30 per cent of that of the control. The depress¬ 
ing effect of sodium carbonate is in evidence in concentrations as low as 
100 p. p. m., and is marked in concentration of 300 p. p. m. 
The relative effect of sodium sulphate and sodium chlorid in depressing 
the absorption of potash is directionally the same as the relative hydroly¬ 
sis resulting from the reaction of the tw T o salts with the calcium car¬ 
bonate present in the culture solution. This suggests that the observed 
effects in the case of sodium sulphate and sodium chlorid may be due 
in part to the accumulative action of the slight amounts of sodium 
carbonate formed in this reaction. 
