The Storage and Use of Soil Moisture 
19 
able number of minimum points shown for several years in fields 
where various crops were growing. Xo minimum points are 
shown below four feet for any crop except winter wheat. The 
other crops shown did not completely dry the soil below four feet. 
The percentages shown indicate that the minimum point of avail- 
able water in this soil is from 7 to 8 per cent. 
STORING WATER IN THE SOIL BY SUMMER TILLAGE 
Storing water in the soil consists of getting the water into 
the soil and then preventing its escape. Summer tillage has 
been the most efficient of all methods of storing water. This is 
to be expected, since the surface is always in condition, if the 
work is properly done, to catch any rain that falls and to check 
evaporation from the surface. Also on properly summer tilled 
land there are no weeds or other vegetation allowed to grow and 
use the water from the soil. In the following tables are given 
data relative to the accumulation of water in the soil. 
Table 4. — Storing moisture by summer tilling. 
PER CENT MOISTURE IN THE SOIL. 
Spring wheat, 1907; summer tilled, 1908. 
Date sampled 
Aug. 24, 
1907 
April 4, 
1908 
May 7, 
1908 
June 3, 
1908 
July 7, 
1908 
Aug. 5, 
1905 
im 
Depth in 
foot 
sections 
1 
2 
3 
4 
5 
6 
7.8 
8.2 
7.9 
8.6 
12.6 
13.9 
14.6 
11.8 
8.8 
10.7 
15.5 
15.0 
19.7 
13.2 
9.5 
11.7 
14.2 
14.4 
21.1 
18.3 
13.5 
12.0 
16.2 
15.3 
22.5 
18.4 
17.5 
16.2 
17.8 
15.7 
16.1 
16.8 
16.3 
16.0 
18.6 
16.9 
14.8 
15.9 
15.5 
16.4 
23.0 
13.1 
Average 
9.8 
12.7 
13.8 
16.1 
18.0 
16.8 
16.8 
Oats, 1908; 
summer 
tilled, 1909. 
Date sampled . ... 
Sept.18, 
1908 
Mar. 30, 
1909 
Apr. 12, 
1909 
May 18, 
1909 
June 29, 
1909 
Aug. 25 
1909 
Oct. 5, 
1933 
Depth in 
foot 
sections 
3 
4 
5 
16 
8.7 
9.0 
9.0 
9.6 
14.7 
14.2 
18.4 
14.4 
9.3 
11.2 
16.1 
15.3 
18.1 
15.3 
9.6 
10.5 
15.3 
14.0 
16.4 
15.0 
9.7 
11.2 
15.6 
14.5 
19.6 
18.3 
17.1 
16.5 
18.5 
15.5 
18.3 
17.8 
16.8 
17.2 
20.4 
18.5 
15.0 
15.7 
15.2 
16.2 
19.6 
18.1 
Average 
10.9 
14.1 
13.8 
13.7 
17.6 
18.2 
16.6 
