US 
Research Bulletin No. 3 
excavated at the base of an olive tree beside which was growing a 
mesquite. The former was about 18 years old, and the latter, 
judging from the number of annual rings, was 11 or 12 years old. 
The roots of the olive did not extend more than 3 feet below the 
surface, but the tap-root of the mesquite extended below the sixth 
foot. On the day before the samples were taken a rain of 0.70 
inch had fallen. 
In the case of the two alfalfa fields the plants were growing 
normally and in the one the roots were evidently deriving much 
of their water from the water-table. However, in both cases the 
moisture of the subsoil to a considerable depth had been reduced 
Table 33. — Moisture conditions in an old alfalfa field near Elgin, 
Nebraska, August 2Jf, 1911. 
Depth 
in feet 
Total water 
Hygroscopic 
coefficient 
Wilting 
coefficient 
Free water 
' 'Water 
available for 
growth" 
Per cent 
Per cent 
Per cent 
1 
12.4 
8.3 
12.2 
4.1 
0.2 
2 to 6 
11.5 
9.3 
13.7 
2.2 
—2.2 
7 to 12 
11.7 
10.2 
15.0 
1.5 
—3.3 
13 to 18 
12.8 
10.1 
14.8 
2.7 
—2.0 
19 to 24 
13.1 
9.9 
14.5 
3.2 
—1.4 
25 to 27 
13.6 
10.3 
15.2 
3.3 
—1.6 
28 to 30 
15.6 
10.1 
14.8 
5.5 
0.8 
31 
18.1 
10.3 
15.2 
7.8 
2.9 
32 
20.1 
10.5 
15.4 
9.6 
4.7 
33 
20.2 
10.0 
14.7 
10.2 
5.5 
34 
21.1 
10.0 
14.7 
11.1 
6.4 
35 
19.9 
9.5 
14.0 
10.4 
5.9 
36 
12.6 
4.7 
6.9 
7.9 
5.7 
Table 34. — Moisture conditions in a naturally subirrigated al- 
falfa field near the Nebraska Experiment Station farm, 
August 4, 1911. The water-table was about 12 feet below the 
surface. 
Depth 
in feet 
Total water 
Hygroscopic 
coefficient 
Wilting 
coefficient 
Free water 
"Water 
available for 
growth" 
Per cent 
Per cent 
Per cent 
1 
10.8 
9.7 
14.3 
1.1 
—3.5 
2 to 4 
13.0 
9.4 
13.8 
3.6 
—0.8 
5 to 6 
14.1 
11.6 
17.0 
2.5 
—2.9 
7 to 8 
22.0 
13.7 
20.2 
8.3 
1.8 
9 
25.6 
13.3 
19.6 
12.3 
6.0 
10 
25.7 
11.0 
16.2 
14.7 
9.5 
11 
26.5 
11.5 
16.9 
15.0 
9.6 
