2ÖO 
EC. MIYAICE. 
second experiment are generally smaller than those of the first experiment 
as will be seen in the following table : 
Salts used 
Toxic amount 
Highest stimulating 
amount 
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For the causes which occasioned this difference, we have not sufficient 
data for an explanation, but it is probably due ist to the exhaustion of 
soil nutrients, 2nd to the presence of toxic salts in large amount already 
at the begining of the experiment, 3rd to the difference of temperature, 
light and other factors, which have influence on the growth of plants, 
since the two experiments were not carried on under the same conditions. 
Loughridge" once investigated the tolerance of alkali by various cul- 
tures. As the result of field observation, he concluded that amount of 
alkali tolerated varies with the variety of the plants and the nature of 
the soil. 
If we again compare the results obtained in the experiment with soil 
with those in pure solutions, we find that the toxic as well as stimu- 
lating effect of each salt appears generally in the latter case with a smaller 
amount than in the former, as will be seen in the following table, with 
the exception of the sodium salts regarding the point of maximum stimula- 
tion. 
1). L o u g h r i d ge.— Bull. No. 133, Agric. Exp. Stat.. Univ. of California, (1901). 
