Oct. 4, 1915 
Effect of Alkali Salts in Soils on Crops 
43 
Table XIV.— Effect of various cations on germination and growth of wheat . Average 
for 5 soils and 10 concentrations for each soil 
Cations. 
Number 
of trials. 
Number 
of plants 
germi¬ 
nated. 
Days to 
come up. 
Average 
height of 
plants. 
Average 
number of 
leaves per 
plant. 
Weight of 
dry mat¬ 
ter per 
plant. 
Chlorid— 
Sodium. 
3 ° 
2 -3 
II. 2 
Inches. 
4*3 
I* 35 
Gm. 
0. 020 
Potassium.— . 
3 ° 
3. I 
II. 6 
5*2 
I* 54 
. 040 
Calcium. 
3 ° 
2.8 
12. I 
4.9 
1. 66 
. 031 
Magnesium. 
30 
3*4 
12. 8 
5 * I 
1. 49 
•039 
Average of chlorids. 
120 
2.9 
II. 9 
4*9 
i* 5 i 
• °33 
Sulphate— 
Sodium. 
30 
7.0 
9.0 
7.0 
1. 77 
. IOI 
' Potassium. 
3 ° 
7. 1 
6. 5 
7*3 
1* 75 
. IOI 
Magnesium. 
30 
7*9 
6. 7 
7*3 
1. 72 
. 105 
Average of sulphates.... 
90 
7*3 
7*4 
7.2 
i* 75 
. 102 
Carbonate— 
Sodium. 
30 
6. 2 
7 * 7 
6. 0 
1. 67 
. 07I 
Potassium. 
3 ° 
6.4 
6.8 
6. 9 
1. 61 
, 087 
Ammonium. 
30 
3*3 
6. 0 
4. 2 
i* i 7 
* 044 
Average of carbonates... 
90 
5*3 
6.8 
5 * 7 
1. 48 
. 067 
Nitrate— 
Sodium. 
30 
3*3 
8. 6 
5*5 
1. 62 
* 035 
Potassium. 
30 
3 * 9 
9.0 
3*4 
1. 29 
.O74 
Magnesium. 
30 
4. 6 
8.8 
5*6 
1. 63 
.052 
Average of nitrates. 
• 90 
3*9 
8.8 
4.8 
1* 5 i 
•054 
A comparison of the various data presented in Tables XIII and XIV 
brings out clearly the fact that the injurious effects of the alkali salts in 
soils may be attributed more to the anion, or acid radical, than to the 
cation, or basic radical. All the chlorids gave results very similar to 
each other. The same may be said of the sulphates and nitrates. The 
different salts of sodium or potassium, on the other hand, differed greatly, 
according to the acid radical combined with them. This is just opposite 
to the conclusions of Kearney and Cameron (13) based on solution 
cultures. 
RELATION OF MOLECULAR WEIGHT IN TOXICITY 
A number of workers have considered the toxicity of various alkali salts 
to be proportional to their osmotic pressure. In order to determine 
whether this were true, the different salts which had been tested were 
arranged in the order of their toxicity and the molecular weight of each 
placed opposite to ascertain whether there was any relation between the 
two. Of course, it is understood that the lower the molecular weight of 
a salt the more molecules there are in a solution containing a given per- 
