32 HINTS ON SOILS AND FERTILIZERS 
duction of one bushel of matured corn. While 
not all crops are as severe on the moisture 
supply as corn, still, most of the farm crops use 
over one hundred barrels of water during a 
single season to produce one bushel of matured 
grain. From these few observations, it can be 
readily seen that the moisture supply of the 
soil is of prime importance. 
We will now turn our attention to the supply 
of rainfall during the growing season. Rain¬ 
fall is usually spoken of in inches. If we have 
one inch of rain during one storm, we can say 
that we have indeed had a heavy shower. When 
such an amount of rain falls in one single 
storm, its quantity can easily be appreciated by 
noting the condition of the roads. Ordinary 
roads will not be suited for automobile travel 
for about two days after such a copious rain 
fall, unless chains are used. In some of the 
“gumbo” soils in the west, a much longer period 
is needed for chains. From this we can get 
a fair idea of what “an inch of rain” signifies. 
Unfortunately, we cannot regulate our rain¬ 
fall. We must take it as it comes. Too often 
it comes at the wrong time, and too seldom at 
the opportune time. However, we must make 
the best of these conditions, unless we are lo¬ 
cated in an irrigation district, where the soil 
is moistened artificially. The rainfall is not 
uniform over the entire country. Some parts 
of the country receive, annually, thirty inches 
or more of rainfall. Such climates are termed 
humid climates. Sections where the average 
rainfall is over twenty inches, but less than 
thirty inches per year, are called sub-humid 
