The Storage and Use of Soil Moisture 
29 
water content until July, and it is not entirely filled with water 
at any time during the season. The moisture chart for the fourth, 
fifth, and sixth foot sections makes a straight line for the entire 
season, showing that there was no change in the amount of water 
in these sections during the entire season. The chart further 
proves that the amount and distribution of the rain was such 
that no great amount of water could be stored. The water did 
not get into the soil to such a depth that it could be conserved. 
DEPTH TO WHICH WATER HAS BEEN STORED IN ONE SEASON. 
The depths to which water can be stored in a given length of 
time depends upon several factors : the type of soil, the underly- 
ing strata, the amount and distribution of the rainfall, the 
amount of water already in the soil at the beginning of the in- 
terval, and weather conditions. 
A light sandy type of soil will absorb water much more 
readily than a heavy type of soil. The same amount of water 
will be distributed thruout a greater area in a light soil than in a 
heavy soil. The maximum carrying capacity is lower in a light 
soil. Furthermore, there is less resistance to the downward 
movement of water thru a light soil. A shallow soil overlying 
a stratum that is practically impervious to water or a layer of 
coarse gravel or sand may require only a small amount of water 
to bring it up to its carrying capacity. In this case any addi- 
tional water would be lost. 
It is obvious that the amount of precipitation and its dis- 
tribution is an important factor in determining the depth to 
which water can be stored in a given interval. Where only a 
small seasonal rain comes, a relatively small amount will be 
held, and consequently a relatively smaller portion of the soil 
will be moistened. An isolated rain even of a considerable 
amount falling on a hot, dry surface is largely lost. The distri- 
bution of the rainfall, therefore, plays an important part. It is 
during rainy seasons where rains are rather frequent that mois- 
ture is most, easily accumulated. 
In the following table are given data to show the depth to 
which water has been accumulated during each of six years. 
Each year two samplings are shown, — one at the beginning of 
the season, the other at the close. — and in every case the field 
was summer tilled : 
