Plants show considerable variation in their resistance to soil alkali. Some varieties of native vegetation grow only where the salt content of the soil is high. Most of the cultivated plants, on the other hand, are injured very decidedly by the presence of large quantities of soluble salts. To this rule there are a few exceptions such as the date palm.
In most of the arid parts of the world there are sections where the presence of alkali is the chief limiting factor in crop growth. Millions of acres of land are in the border zone between complete freedom from alkali and a concentration that would prohibit crop production. Crops must be found for this land. Good judgment directs against the use of crops that are sensitive; the yield of resistant crops is reduced much less by the presence of salt than that of the sensitive ones. It becomes important, therefore, to determine the relative resistance of the various crops in order that a more intelligent selection may be made.
The experiments reported in this bulletin were undertaken to throw some light on the subject as to the relative germination and early growth of different crops in alkali soil. Different varieties of the same crop as well as different crops were tested. A great deal of work has been done on this subject by other investigators, but space in the present publication does not permit this work to be reviewed.
Harris, F. S. and Pittman, D. W., "Bulletin No. 168 - Relative Resistance of Various Crops ot Alkali" (1919). UAES Bulletins. Paper 134.