The Marietta journal. (Marietta, Ga.) 1918-1944, 1919-07-11
The Relation of Drainage
to the Soils of Georgia
By GEORGE A. CRABB, Athens, Ca

Drainage has been practiced for
centuries by all countries of advanced
civilization because of the dement's
it has brought to the health of the
people. Yet from the agricultural
standpoint we find that drainage has
received greatest attention only In
the past fifty years. Only recently
have we known that proper drainage
is the basis for all permanent soil
Improvement. From the agricultural
standpoint drainage is essentially a
soil problem since the soil is the fun
damental basis of all agricultural
work. Therefore, if the agricultural
conditions are to be permanently inn
proved. the health of the plant must
be considered in order that all soils
may produce yields in accordance
with the plant food that they con-
tain or which may be added to them
in the form of manures or fertilizers.
There are conditions which must
be maintained in the soil in order
that plants may grow and make re-
turns. When these conditions are
most nearly ideal yields will be larg-
est. In order that plants may grow
they must be supplied with home
in which their roots act as anchors
and feeders. A proper temperature
must be maintained. Air in sufi-
cient quantities must be supplied
while food and water must be given
at all times during the period of
growth. Light is also an essential
that must be supplied in order that
the proper assimilation of food may
be made within the plant tissues.
All of the conditions noted are di-
rectly affected by the soil with the
exception of light and all are like
wise affected by the condition of
drainage in the soil.
Water is largely controlling fac
tor in plant growth 1t is not only
a food but is the carrier of food into
the plant. Plant food obtained from
the soil must be in the form of
weak solution before it can be used
by the plants, and water is, therefore,
essential to the supply of food to
plants. Since the solution must be
very weak in order that plants may
use it, large quantities of water are
passed through the plant and lost
by Transportation in order that enough
food may be supplied for the needs
of the crop.
Water occurs in the soil in three
forms known as Microscopic, Capil-
larry or Film and Gravity or Free
water. The first is not sufficient to
maintain plant growth. The latter is
absolutely injurious to plant growth
while the Capillary or Film water is
the only form used for plant growth.
The quantities of water needed to pr
duce crop are very great in proper
tion to the dry weight of the matured
crop. Experiments show that in or
der to produce a corn crop of 100
bushels with the fodder necessary to
grow that amount of corn it will be
necessary to furnish from 1900 to
$500 tons of water. Therefore, in
order to supply this amount in the
form of Capillary or Film water, the
soil must be kept in the very best
physical condition. This can be done
only when the soil is properly drained
of the free or injurious water and
an abundant supply maintained in
he that tho
The reason why wet and undrained
soils are unproductive is because farm
crops cannot use the free moisture
and because the air is excluded by the
water. This condition results in the
formation of acid in the soil and also
other conditions that are toxic to
farm crops. Unproductive, un-
drained soils can be made to produce
farm crops by draining away the free
water in order that the soil may be
properly ventilated after which plow-
ing, cultivation, lining and other
practices may be followed making
the soil proper habitation for crops.
Drainage is, therefore, one way of
controlling soil moisture, by remov-
ing the form of it that is injurious
to the growth of crops.
The benefits of drainage in so far
as agriculture is concerned may be
summed up in general by saying that;
1. Drainage removes the excess
water from the soil both from the
surface and from the pores of the
soil This renders the soil more firm.
Soil that is poorly drained is likely
to be injured in its physical struc-
ture either by tillage operations or
by the trampling of animals. This
condition may be very injurious to
the growth of farm crops.
z. Drainage promotes the venti-
iation of the soil. Oxygen is neces-
sary for the growth of desirable or
ganisms in the soil swell as for the
chemical changes which take place
in the preparation of plant food from
the organic and mineral matter in
the soil. In saturated soil the pores