CROPS OX ALKALI LAND, HUNTLEY PROJECT, MONTANA. 5 
GROUND WATER. 
For the purpose of determining the depth of ground water at dif- 
ferent times of the year, four wells have been made on the experi- 
ment tract, and measurements were made biweekly during 1913. 
The results of these measurements are shown in figure 1. The aver- 
age depth to ground water during 1913 was 3.14 feet. This ranged 
from 3.76 feet on March 6 to 2.02 feet on October 2, the most rapid 
rise occurring during the latter part of the irrigation season. 
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Fig. 1.— Diagram showing the depth to ground water on the AVorden tract during the year 1913. 
Samples of the ground water were taken from each of these wells 
during the season of 1913 from June to November, and nine samples 
from each well have been analyzed. The average results of these 
analyses are given in Table I. 
Table I. — Results of analyses of ground water from the Worden tract in 1913, showing 
the percentages of the substances indicated. 
Well No. 
Total 
salts. 
CaO. 
MgO. 
Na 2 0. 
C0 3 
HCO3 
CI. 
S0 4 . 
A-l. 
A-2. 
B-l. 
B-2. 
Average. 
1.383 
2.829 
1.512 
1.165 
0. 0549 
.0737 
.0178 
.0193 
0.0719 
■ . 1289 
.0521 
.0268 
0.437 
1.001 
.566 
.431 
None. 1 0.0277 
None, i .0381 
0.0026 .0169 
.0096 .0370 
1.722 
.0414 
.0030 
.0299 
0. 0136 
.0294 
.0109 
0.952 
1.901 
1.027 
Table I shows that the water contained an average of 1.722 per 
cent of total salts and that these consisted chiefly of sulphates. This 
amount is equal to 1.07 pounds per cubic foot of water. Analysis of 
the soil showed that it contained an average of 1.77 per cent of total 
salts. Assuming that a cubic foot of the soil weighs 75 pounds and 
that it contained an average of 15 pounds of water, this amount would 
be equal to 1.32 pounds of soluble salts per cubic foot of moist soil, or 
the concentration of salts in the soil water would be about 9 per cent. 
This concentration is about five times as great as that of the ground 
water. 
