382 
Journal of Agricultural Research 
Vol. I, No. 5 
farming area is situated, was in all probability once covered with sage¬ 
brush vegetation, although few traces of it now remain. Here the condi¬ 
tions were probably more favorable for the growth of this plant than in 
most of the area still occupied by it. 
Salinity. —Reference to Table IV shows that in the typical sage¬ 
brush land of Tooele Valley the salt content of the soil is extremely low— 
lower, in fact, than in many soils of humid regions. Near the lines of con¬ 
tact with other associations, however, Artemisia iridentata frequently 
grows where much salt is present at a depth of 30 or 40 inches. In such 
places the saline subsoil is an effectual barrier to the penetration of the 
roots, the depth of soil from which the plant must extract its entire 
supply of water is correspondingly limited, and as a result the plants are 
scattered, very small, and give every appearance of suffering from 
drought. 
An excellent example of this condition was observed on the west side 
of the valley, where in a spot of considerable size the plants of Artemisia 
were widely spaced, rarely more than 2 feet high, and had many dead 
branches. Samples of soil collected in this spot on June 3 gave salt 
contents and moisture contents as follows: 
Tabi,E V .—Salt content and moisture content (above or below the wilting coefficient) at 
different depths of the soil where the sagebrush was small and suffering . 
Depth. 
Salt content. 
Moisture con- i 
tent above or j 
below wilting j 
coefficient. ! 
1 
Feet . 
Per cent. 
i 
Per cent . 
I 
O. 05 
— 2. O 
2 
. 18 
— 2. 2 
3 
• 53 
“3-4 
4 ' 
. 64 
+ .8 
5 
• 59 
i 
The roots of the plant alongside this boring penetrated to a depth of 
only about 2 feet, at which point the taproot had died, and development 
was continued by horizontal laterals. The feeding roots were mostly 
confined to the first foot of the soil. 
The most extreme condition as regards salinity which was noted at any 
point in Tooele Valley where Artemisia iridentata grew was in a small 
pocketlike depression among the sand hills where salts had accumulated 
as a result of seepage from the surrounding dunes and where very small 
sickly plants of sagebrush grew in company with greasewood (Sarcobatus) 
and Kochia. The salt contents were as follows: First foot, 0.16 per cent; 
second foot, 0.51 per cent; third foot, 0.67 per cent; fourth foot, o.66 
per cent. The presence here of living plants of sagebrush is doubtless 
explained by the fact that large seed-producing plants of this species 
were growing on the surrounding dunes and that the salt content of the 
