A drain scoop should be used in bottom of the trench to make a resting place for the tile that will prevent any displacement by the soil when the trench is filled.
Depth of Trenches.—Underdrains may be placed too deep in close soils for best results. In an early day it was advised that the drains be put down 4 feet deep. We now know that a tight clay soil may give best results from a drain only 28 inches deep, or even a little less. In a looser soil 3 feet is a better depth, and in porous swamp lands the drain may well go 4 feet deep, thus permitting increase in distance between drains.
Connections.—The laterals should enter the branches and mains near the top, so that the water will be drawn out rapidly. The tile should be laid with close joints at the top, so that the water may enter more freely from the sides than the top. No covering other than moist soil is needed unless there is very fine sand, when paper over the joints will serve a good purpose. After some moist soil from the sides of the trench has been tramped upon the tile, the trench may be filled by use of a breaking-plow or winged scraper.
Permanency Desired.—The expense of underdrainage demands care in every detail of the work. The grade of the trenches should be carefully tested. Every piece of tile should be examined. The outlet should be guarded against displacement or entrance by animals. A good plan is to lay the last few pieces of tile in a close-fitting wooden box, and to protect the end with iron rods placed 2 inches apart.
If the drain is on a true grade, so that no silt will collect, there need be no fear concerning its continued efficiency, provided water does not run in it all the time. If it carries the water from springs continuously, plant-roots may fill it, and tree roots are quite sure to do so when opportunity offers. This is notably true in case of elms and willows, but protection is afforded in such an instance by closing the joints with cement.
The lure of the country.
The following pages contain advertisements
of books on kindred subjects
NEW FARM AND GARDEN BOOKS