UNDER-DRAINING.
The advantages of under-drains over open drains are very great.
When open drains are used, much water passes into them immediately from the surface, and carries with it fertilizing parts of the soil, while their beds are often compacted by the running water and the heat of the sun, so that they become water tight, and do not admit water from the lower parts of the soil.
The sides of these drains are often covered with weeds, which spread their seeds throughout the whole field. Open drains are not only a great obstruction to the proper cultivation of the land, but they cause much waste of room, as we can rarely plow nearer than within six or eight feet of them.
There are none of these objections to the use of under-drains, as these are completely covered, and do not at all interfere with the cultivation of the surface.
With what materials may under-drains be constructed?
Describe the tile.
Under drains may be made with brush, stones, or tiles. Brush is a very poor material, and its use is hardly to be recommended. Small stones are better, and if these be placed in the bottoms of the trenches, to a depth of eight or ten inches, and covered with sods turned upside down, having the earth packed well down on to them, they make very good drains.
TILE DRAINING.
The best under-drains are those made with tiles, or burnt clay pipes. The first form of these used was that called the horse-shoe tile, which was in two distinct pieces; this was superseded by a round pipe, and we have now what is called the sole tile, which is much better than either of the others.