UTAH ACADEMY OF SCIENCES 131 
EFFECT OF SOIL ALKALI ON PLANT GROWTH. 
By F. S. HARRIS. 
(Summary). 
Results of over 18,000 determinations on the effect of 
alkali in the soil on the germination of seeds and the growth 
of plants were presented. From these data the following 
conclusions were drawn: 
The effect of the various alkali salts in soils on plant 
growth and the quantity of alkali that must be present to 
injure crops are of great practical importance to farmers 
in arid regions, as well as of considerable interest to the 
scientist. 
Only about half as much alkali is required to prohibit 
the growth of crops in sand as in loam. 
Crops vary greatly in their relative resistance to alkali 
salts, but for the ordinary mixture of salts the following 
crops in the seedling stage would probably come in the 
order given, barley being the most resistant: Barley, oats, 
wheat, alfalfa, sugar beets, corn, and Canada field peas. 
Results obtained in solution cultures for the toxicity 
of alkali salts do not always hold when these salts are ap- 
plied to the soil. 
The percentage of germination of seeds, the quantity 
of dry matter produced, the height of plants, and the num- 
ber of leaves per plant are all affected by alkali salts in 
about the same ratio. 
The period of germination of seeds is considerably 
lengthened by the presence of soluble salts in the soil. 
The anion, or acid radical, and not the cation, or basic 
radical, determines the toxicity of alkali salts in the soil. 
Of the acid radicals used, chlorid was decidedly the most 
toxic, while sodium was the most toxic base. 
The injurious action of alkali salts is not in all cases 
proportional to the osmotic pressure of the salts. 
The toxicity of soluble salts in the soil was found to be 
in the following order: Sodium chlorid, calcium chlorid, 
potassium chlorid, sodium nitrate, magnesium chloride, 
