Feb. x6,1914 
Indicator Significance of , Vegetation 
39i 
TablU IX .—Kochia association: Moisture conditions and salt content of the soil in 
typical areas. 1 * * 4 
Date of collection. 
Item. 
No. of sample. 
Moisture equivalent. 
Wilting coefficient. 
Depth 
of soil 
(feet). 
Moisture content above 
or below wilting coeffi¬ 
cient. 
Salt content. 
June. 
July. 
August. 
Aver- 
1 
1 
7 
18 
18 
3 
5 
12 
3 
7 
age. 
4 
S 
32 
44 
45 
65 
70 
78 
105 
116 
23. 0 
35- 8 
21. 7 
26. 0 
24. 7 
23-9 
2 5-& 
25 - 5 
25* 2 
30*3 
26. 4 
29.4 
25-3 
27.0 
33-3 
35 * O 
29 - 4 
34*5 
36. 8 
32-4 
33 * 5 
31-4 
34-2 
24.4 
35 *o 
34-3 
32 . 5 
31 - 9 - 
12. 5 
19. 5 
11. 8 
14. 1 
13. 4 
13. 0 
14. 0 
13 - 9 
13-7 
16. s 
14*3 
16. 0 
13 - 7 
14. 7 
18. 1 
18. 7 
17. 6 
18.2 
17. 0 
18. 6 
19. O 
18. 6 
17. 7 
17. 3 
— 1.8 
—6. 2 
—5.8 
—5. 4 
—i. s 
—2. 6 
+ 1. 6 
—6. 1 
— 1.8 
— 5 * 4 
— 2. 0 
— 2- 0 
—2. 5 
—3. 2 
+ i-6 
—2. 4 
•05 
.08 
.04 
. 22 
• 14 
.07 
.06 
.18 
• 3 i 
•05 
. 12 
• 3 ° 
. 16 
.14 
1. 20 
•30 
•47 
•32 
.80 
1. 49 
• 3 i 
•55 
.82 
. 60 
• 52 
1. 14 
x. 56 
1.10 
.88 
1.36 
1.36 
.92 
1. 02 
• 70 
.78 
1. 02 
i *43 
•97 
1. 76 
1.10 
1.11 
1 All data in this table are stated in percentages of the dry weight of the soil. The moisture contents 
with a plus sign ( + ) represent moisture available for growth (above the wilting coefficient), while those 
with a minus sign (—) represent a corresponding deficit of available moisture (below the wilting coefficient). 
Soil, Moisture. —The moisture equivalents given in Table IX indi¬ 
cate that the moisture-holding capacity of the soil is much higher in 
Kochia land than in sagebrush land. The moisture contents in typical 
areas show that as early as the first of June, 1912, the soil to a depth of 
4 feet was usually devoid of water available for plant growth. The 
deficit was usually greatest in the surface foot, partly no doubt because 
of surface evaporation and partly because of the shallow-rooting habit of 
Kochia vesiita. 
Salinity. —The soil in typical Kochia land, at least in Tooele Valley, 
is usually free from an injurious quantity of salts in the surface 
foot. On the other hand, the second foot is usually, and the third and 
fourth feet are almost invariably, highly saline. In places where the 
surface foot contains much salts the plants of Kochia are scattered and 
stunted. 
There is some evidence that the presence of Kochia vegetation, al¬ 
though in the great majority of cases associated with a strongly saline 
subsoil, does not* invariably indicate such a condition. In the upper 
part of Tooele Valley an island of Kochia (PI. XUII, fig. 2) several acres 
in extent, in the midst of the sagebrush zone, was found to be underlain 
at a depth of 30 inches by a gravelly hardpan. The soil just above this 
stratum contained only about 0.2 per cent of readily soluble salts. It 
would seem that here the presence of hardpan rather than of salts had 
caused the Artemisia to give place to Kochia. 
