IS 
Research Bulletin No. 5 
In Table 2 we give the results of a series of determinations 
made to ascertain the maximum water-holding capacity of this 
type of soil. On September 9, 1908, the amount of water present 
in the soil was determined. After making this determination, an 
excavation eight feet in diameter and one foot deep was made. 
A total of thirty-six inches of water was put into this to insure 
saturation, and the dry earth, which had been removed in ex- 
cavating, was put back as a mulch. About six or eight inches of 
hay was put over all of this in order to reduce surface evapora- 
tion to a minimum. 
Samples were taken from time to time, as shown in the table, 
to determine the movement of the water. We note that between 
the sampling of September 17 and October 9, 1908, there is a 
loss of 3 per cent, or a total of five inches of water. It is evident 
that this water moved downward, as the first foot shows con- 
clusively that the water did not escape from the surface. This 
section of the soil was not sufficiently moist to lose much water. 
Just after the sampling on October 9, a three-inch rain fell, which 
explains the increased amount of water found October 20 We 
then find a decrease to April 22, 1909. when the upper six feet 
of soil have on an average about 16 per cent of moisture. There 
is an increased amount again when the rains start during the 
summer, but it drops later in the season. It would seem then 
that the maximum water-holding capacity of our soil is between 
It; and 18 per cent. ( All moisture percentages given in this bul- 
letin are figured on the basis of the dry weight of the soil; for 
example. 10 per cent represents that for each one hundred units 
of dry soil that there are ten units of water present.) 
Table ^.—Minimum point of exhaustion of soil tvater by the crop. 
Crop 
Per cent moisture in the soil 
1st ft. 
2d ft. 
3d ft, 
4th ft. 
5th ft, 
6th ft. 
7.1 
7.4 
7.9 
8.6 
8.0 
7.1 
8.0 
7.1 
7.7 
9.1 
8.4 
6.7 
8.2 
7.4 
7.7 
8.9 
8.1 
7.3 
8.5 
7.4 
7.7 
9.6 
8.3 
7.1 
7.8' 
Oats 
7.4 
Corn 
Cane 
Barley 
Table 3, giving the minimum point to which crops can use 
the water from this soil, was obtained by averaging a consider- 
