IMPROVING FARM LAND 
163 
of the growing plants to decay and their leaves turn 
yellow and soon die. Too much water in soil also aids 
the development of wilt and other fungous growth. Use¬ 
ful bacteria will not work in poorly drained soils, and 
cultivation is almost impossible. 
Kinds of Drainage.—The kinds of drainage may be 
classified as open ditch, blind ditch, and tile drains. 
(Figs. 117b-118.) The open ditch system is most widely 
used and is probably the cheapest in point of construc¬ 
tion. In preparing open ditch drains it is important that 
they should be made with the proper grade and width to 
carry the water. The narrow, deep, spade ditch is a 
menace to southern farmers in that it erodes the soil 
rapidly. The latter type of ditch is also objectionable 
when hauling from one section of the field to another. 
The blind ditch drains are constructed by first digging 
a ditch of the desired grade and width. Poles or rocks 
are then placed in the ditch and are covered over with at 
least eighteen inches of dirt. 
Tile drains are not used extensively in the South. This 
is due to cheap land, the tenant system of farming, and 
the cost of installing the drainage system. 
Terracing is the building of ridges along the hillsides 
to prevent washing and the loss of fertility. While it is 
probable that much of the water falling upon the hillside 
will run off, the terrace prevents the sudden rush of water. 
It provides a side drain which carries the excess water 
gradually away. In the meantime, the greater amount 
is^libsorfed by the soil and remains for supplying plants 
with moisture. 
Terraces are ridges some ten or twenty feet wide, at 
distances of about fifty or one hundred feet upon the 
side of the hill. These ridges are about two feet high and 
will not interfere with cultivation. These terraces are 
