Evening times-Republican. [volume] (Marshalltown, Iowa) 1890-1923, 1908-07-23
Tile Drainage.
lTha Earnerl

Il
The main object of drainage is to
rid the soil of surplus water, which
prevents plant growth, but there are
several other things accomplished
with the removal of the water. The
first is that soils that are drained have
! better ventilation. All plant roots
require air and when the soil spaces
are filled with water there is little
air there Soils are ventilated by
drainage in several different ways.
First, as the soil dries out it sinks
and leaves cracks thru which the
air can pass; second, the lines of tile
themselves form passageways thru
which air is forced with every change
in atmospheric pressure; third, when
water from q heavy rain passes off
thru the drains fresh air is drawn
in behind it. The drainage increases
the room which roots occupy by low
ering the ground water in the soil. 1t
also makes the ground warmer as the
amount of water that comes to the sur
face for evaporation is decreased. By
getting rid of the surplus water the
amount of soil moisture that is avail
able to the plant is increased. In
laying out drainage system the first
thing to do is to decide on the loca-
ton of the outlets. This should be at
the lowest available point so as to get
the greatest amount of fall. The main
drain should follow the line and d.
rection of the lowest lying ground.
The size of the main drain will de-
pend upon it's fall and the area which
it drains. The greater the fall the
smaller may be the tile. A four-inch
main is ordinarily sufficient for ten
to twelve acres. For laterals three
inch tile will usually be found salts
factory. One danger in using small
tile is it does not take much sediment
to fill them up. The main can be To-
Gated in the center of the area and the
laterals branch off from either side or
on comparatively fiat piece of ground
where there are no particular LOVELY
ing channels. 1t is better to locate
the main drain at one end or side
and place the laterals in parallel lines
from one side The depth Of the drain
will depend upon two conditions; the
nature of the soil and the average
distance of the soil and the average
distance of the. ground water below
the surface. -Four feet is usually con-
sidered deep and two feet shallow
drainage The distance apart of the
drains will depend on the depth. The
distance apart is also dependent upon
the texture of the soil thru which
the water has to filter. In fine clay
soil tile should not be placed deep but
close together. In laying tile 1t should
be begun at the outlet. Have the
first few feet Of very hard burned
tile or glazed sewer pipe which
will not be injured by freezing and the
outlet walled up with stone to prevent
washing or falling down Of dirt and
with some sort of grating to keep out
burrowing animals. The laying of tile
should follow soon after digging the
ditch Either Y or 7 should always
be used making connection with the
laterals. The upper ends Of all lines
should be closed with flat stone or
brick. The ditch may either be filled
with a shovel or horse scraper. AS to
the cost Of drainage. it may be stated
that most agricultural land could
be thoroughly drained for from $25 to
$40 per acre, while many low fields
could be greatly improved by single
line costing from. $40 to SIS per acre.
The first cost is high, but it is the
only cost if the work is properly done.