THE BEET-SUGAR INDUSTRY IN 1920. 23 
Natural drainage. — Fortunately a large part of the tillable area 
now devoted to sugar-beet culture has a natural drainage. This 
may be due to one of several conditions. 
(1) The surface of the ground may be sufficiently rolling to drain 
naturally. In some instances the slope is so great that the water 
passes off too quickly, and consequently the land is unproductive 
because of excessive surface drainage. 
(2) Certain areas have a natural drainage due to a sloping sub- 
soil. As previously noted, some areas have a subsoil that is more or 
less impervious to water. If the impervious subsoil is sloping, the 
water falling upon the surface soil will pass through to the subsoil 
and gradually disappear along the sloping subsoil. In this case 
natural drainage is satisfactory and needs no particular attention, 
provided the impervious subsoil is not too near or too far from the 
surface, and provided further that there is a natural outlet, so that 
the water will not eventually back up along the slope or incline of the 
subsoil. 
(3) The natural drainage accomplished by means of a porous sub- 
soil has been already noted. There are localities in which the sub- 
soil is so porous that it is almost impossible to hold sufficient water 
in the seed and root beds to produce a crop of beets. There arc 
therefore localities in which the natural drainage is of such a nature, 
either through a lack of moisture or through an excess of water, 
that natural drainage constitutes a limiting factor in sugar-beet 
production. 
(4) On the other hand, there are areas and fields in which arti- 
ficial drainage must be practiced in order to put the soil in condition 
for sugar-beet production. Several systems of artificial drainage 
are in general use. 
The open ditch. — An open ditch constitutes one of the methods 
by which this limiting factor of excessive moisture is removed. It 
is the least expensive method of providing artificial drainage, espe- 
cially from the standpoint of labor and material involved. How- 
ever, considerable tillable ground is lost through the construction of 
open ditches. This loss is due to the space occupied by the ditch 
and by the ditch bank. In constructing an open ditch these points 
should be kept in mind, so that the least possible loss of tillable area 
will result. The open ditch constitutes a barrier which can not 
readily be crossed in the usual farming operations. It is advisable, 
wherever practicable, to construct these ditches along the edges 
of the field, along roadsides, and in places where they will inter- 
fere least with the farming operations. Sometimes it is necessary 
to cross the fields with ditches in order to drain the soil properly; 
in such cases the fields and ditches should be so laid out that the 
