Well Drained Soil Is More Productive
Farmers well know the value of draining excess water from their land. Cash crops do not tolerate soggy, mucky ground and a large amount of productive soil would not be in use were it not for modern drainage techniques. The amount of tile that must be installed depends greatly on the type of soil. Clay loam requires considerably more drainage capacity than 'tobacco sand'. Some strategies involve a systematic approach, with the tile runs laid out in a regular grid-like fashion. This works well for heavier ground, but isn't necessary and could even be counterproductive in very light soils. In some areas artificial drainage may not be necessary at all. An experienced contractor will be able to determine the appropriate solution for any particular situation.

A large open drain being excavated

Some unusual situations contractors sometimes find themselves in.

Simple Is Better: The Evolution of Drainage Tile
Farm drainage was not common until the mid 20th century. Previous to mechanization installing tile drains was generally very difficult and expensive to accomplish. However, in areas where the soil was rich it was often worth the cost and effort. Various types of clay drainage tile were laid in hand dug trenches, Sometimes the work was performed by the farmer himself, with no other help. Only the most necessary drains would be trenched in, usually under a hot summer sun. In the early days tile were produced in some unusual tubular shapes. They were usually about a foot in length and three inches or larger in diameter, but the cross section underwent considerable experimentation. Some of the historical examples shown here include  flat bottom ovals, six sided hexagon shapes and 'shin' tile. A basic round shape proved to be not only the most effective tile to use, but also the cheapest. According to one source, "shin tile" were made by taking a square piece of pliable clay and bending it over one's lower leg to shape it. They were apparently laid on top of boards in soil conditions where the ground was too soggy to lay them on the trench bottom. Eventually technology provided us with cheap corrugated plastic tile in a variety of diameters and structural strength. Usually delivered and installed in 250 foot lengths, four inch diameter plastic tile are the most  commonly used in farm drainage. Six inch diameter tile are also utilized and typically lead to municipal drains or ditches.