416 
Journal of Agricultural Reserach 
Vol. I, No. 5 
SUMMARY 
In Tooele Valley the different types of native vegetation indicate the 
conditions of soil moisture and salinity of the land on which they are 
found and thus afford a basis for estimating its capabilities for crop pro¬ 
duction. These correlations are stated in Table XVIII (p. 413), Table 
XIX (p. 413), and Table XX (p. 414). 
The sagebrush (Artemisia tridentata) association covers the land 
nearest the mountains where the soil is of rather light texture, perme¬ 
able, rather low in moisture-holding capacity, and free from an excess 
of alkali salts and where under natural conditions the moisture available 
for growth is usually exhausted early in summer. A good stand and 
growth of sagebrush indicates land that is well adapted to both dry 
farming and irrigation farming; but where the stand is thin and the 
growth poor the depth of good soil is usually too small for profitable 
crop production, at least without irrigation. 
The Kochia ( Kochia vestita) association covers areas lying just below 
the sagebrush belt and also occupies islands in the midst of the latter 
vegetation. The soil, which is remarkably homogeneous, differs from 
that of sagebrush land in its finer texture, relative impermeability, 
higher moisture-holding capacity, and the high salt content of the sub¬ 
soil. The first foot of soil is usually free from an injurious quantity of 
alkali salts. Moisture available for growth is usually wanting during 
the summer to a depth of at least 4 feet and probably to a much greater 
depth. Dry farming is precarious on such land, owing to the small 
depth of soil free from alkali. Even under irrigation the relatively 
impervious nature of the soil might hinder washing out the salts to a 
depth which would permit profitable crop production. 
The shad scale (A triplex confertifolia ) association occupies the land 
next below the Kochia belt. The soil is similar, in the main, to that 
where Kochia occurs, but frequently contains much gravel, is usually 
even drier during the summer months, and has on the average a some¬ 
what smaller salt content. Dry farming is nearly as precarious on 
shadscale land as on Kochia land, but where water is available for irri¬ 
gation the salts could probably be leached to a greater depth than on 
Kochia land, the soil being more permeable. 
The greasewood-shadscale (Sarcobatus vermiculatus and Atriplex con - 
fertifolia) association occupies a belt lying between the pure shadscale 
vegetation and the salt flats and also crowns the ridges and knolls which 
intersect the latter. The soil differs from that of any of the foregoing 
associations in usually containing, during the summer, moisture available 
for growth at all depths below the surface foot. It is also strongly 
saline below the depth of 1 foot, and even the surface foot often con¬ 
tains a considerable quantity of salts. Land of this type is not suitable 
for dry farming, but can be made to produce good crops under irriga¬ 
tion, especially when drainage is provided. 
