Voiv. XXVII Washington, If. C., March 22, 1924 No. 12 
THE OSMOTIC CONCENTRATION, SPECIFIC ELECTRICAL 
CONDUCTIVITY, AND CHLORID CONTENT OF THE 
TISSUE FLUIDS OF THE INDICATOR PLANTS OF 
TOOELE VALLEY, UTAH 1 
By J. Arthur Harris, Collaborator, Bureau of Plant Industry; R. A. GortnER, 
formerly Field Assistant, Biophysical Investigations and Alkali and Drought Resistant 
Plant Investigations; W. F. Hoffman, formerly Field Assistant, Biophysical In - 
vestigations and Alkali and Drought Resistant Plant Investigations; J. V. Lawrence, 
formerly Field Assistant, Alkali and Drought Resistant Plant Investigations; and 
A. T. Valentine, formerly Field Assistant, Biophysical Investigations and Alkali 
and Drought Resistant Plant Investigations, Bureau of Plant Industry, United States 
Department of Agriculture 
INTRODUCTION 
During 1911-1913 Kearney, Briggs, Shantz, McLane, and Piemeisel 
(24) 2 conducted a detailed investigation of the relationship between the 
plant associations and the soil conditions of Tooele Valley, Utah. The 
purpose of this work was to ascertain to what extent natural vegetation 
may serve as an index of soil conditions, and in consequence as an indi¬ 
cator of the suitability for agricultural development of the soils of a dry 
and in part highly saline region. The work was a natural outcome of 
the interest in indicator vegetation aroused by a paper on the plains 
region by Shantz (27). 
With the exception of early papers by Hilgard and his associates, these 
were pioneer investigations on the utilization of the native, vegetation of 
the United States as a means of estimating the adaptability of the soil 
for agricultural purposes. The problem of indicator vegetation has since 
been treated more extensively by Clements (2). 
The investigations by our predecessors (24) included extensive deter¬ 
minations on 3 ie physical and chemical characteristics of the soil. They 
investigated moisture content, moisture equivalent, wilting coefficient, 
salt content, and electrical conductivity of the soil solution as measured 
by the Wheatstone bridge, in typical areas of the more important plant 
associations. Their studies show that it is possible from an inspection 
of the vegetation to draw fairly definite conclusions concerning the 
physical and chemical properties of the soil. They correlated these two 
kinds of information with the results of agricultural experience in this 
region, which has long been the locus of limited but intensive and intelli¬ 
gent crop production, both with and without irrigation. 
At the time these studies were made, methods for the precise measure¬ 
ment of the physicochemical properties of plant saps in the field were 
not available. It was not, therefore, possible for these authors to 
+ 
1 Received for publication Feb. 16, 1924. 
* Reference is made by number (italic) to “ literature cited,” p. 922-924. 
Journal of Agricultural Research, 
Washington, D. C. 
Vol. XXVII, No. 12 
March 22, 1924 
Key No. G-410 
85607—24-1 
(893) 
