FOUR] WATER SUPPLY 
from the atmosphere. If not stirred, a crust is soon 
formed against the air and moisture. At the same 
time that the loose soil absorbs and retains the 
moisture, it takes in, with the water, fertilizing ele- 
ments from the surface and the air. 
We must also anticipate another point, that 
drainage is quite as truly a method of keeping soil 
moist as it is of keeping it from being wet. Con- 
tradictory as this may seem, it is nevertheless true 
that good drainage is one of the best ways of pre- 
venting serious damage from drought. Undrained 
land is soggy in wet weather, but is not retentive of 
moisture in dry weather. It bakes hard, and vege- 
tation is killed outright. There is hardly a piece of 
land in existence that will not be better fitted for 
resisting a dry spell by being well underdrained. 
Tile or stone drains should be placed from twenty 
to one hundred feet apart and three to four feet 
below the surface. The cost will, of course, vary 
quite largely —from fifteen dollars per acre to forty- 
five or fifty. The profit, however, derived, in the 
way of increased crops and decreased damage from 
drought, will compensate the land-owner very speed- 
ily. I have found, still further, that good drainage 
enables the roots of many plants —such as alfalfa 
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