22 
Research Bulletin No. 5 
inches of water were retained from a rainfall of 12.7 inches. 
This was about 12 per cent of the total rainfall. It will be noted 
that this field contained almost as much water the middle of 
June as it did at the close of the season. On June 15 it had 
available moisture to a depth of five feet. The field was in good 
condition, from a moisture standpoint, to seed to a field crop such 
as cane. Or. if one were preparing to seed alfalfa, the early 
spring cultivation not only prepares the seed bed and gets rid 
of weeds, but accumulates moisture to start the crop. From the 
data given in this table, there have been two years, 1908 and 1912, 
when water was accumulated to a depth of several feet in time 
for seeding alfalfa by the middle of June. A stand of alfalfa is 
much more certain with several feet of moist soil for a seed bed 
than where only the surface is moist. 
From the table and the discussion of it, we find that the 
amount of water which can be stored varies greatly with the 
different years. The per cent of the total rainfall held varies 
from 10 to 33 per cent. During the summer of 1908, there were 
eight rains of more than one-half inch each, three of which were 
more than an inch each. There were also rainy periods when 
light rains came so close together that the surface soil would be 
wet from one rain until the next and, therefore, even a small rain 
would penetrate below the surface. During the summer of 1910. 
only three rains came of more than one-half inch, two of which 
were over an inch. The season of 1911 was better from the 
standpoint of total amount of rain, but the distribution was such 
that the moisture could not be held. During dry seasons, with 
the high rate of evaporation and extremely hot surface soil, 
a half inch of rain may be lost before it gets into the soil 
deep enough to be retained, if it comes as an isolated show r er. 
Where the surface is dry, a rain of less than one-half inch is of no 
value whatever in storing water, tho it may be of great value to 
the crops. A half inch of water will not get thru the loose mulch 
on the surface unless the mulch is still moist from a previous 
rain. 
It is also noted from the tables that the water content was 
not increased below three feet in 1910 or 1911. In 1912 it was 
increased to five feet, while in 1908 and 1909 the soil was filled 
as deep as the samples were taken. The weather records for the 
years under consideration show the causes of the variation in the 
results of storing moisture as shown in Table 4. The table 
shows that during some seasons, when the rainfall is low or 
poorly distributed, it is impossible to accumulate much water in 
the soil by summer tillage. 
