EXTENSION COURSE IN SOILS. 75 
MARSH SOILS. 
(Ref. No. 2, pp. 64-68.) 
Marsh soils are those which are naturally wet most of the year 
and contain moderate or large quantities of organic or vegetable 
matter. Such soils are formed in marshes occurring along the valleys 
of the larger rivers, along seashores where they are known as tidal 
marshes, and generally throughout the area which was covered by 
the last glacial ice sheets, where they were caused by the gradual 
drying up of hundreds of shallow lakes and ponds. (Ref. No. 3, 
pp. 41-43.) 
Composition. — Marsh soils vary greatly in chemical composition, 
especially in the amount of organic matter they contain. (Ref. 
No. 7, pp. 123-125.) It is customary to speak of those which contain 
moderate quantities of vegetable matter together with considerable 
quantities of soil and earthy matter as mucks, while those which 
consist largely of organic matter are called peats. As a rule, soils 
which would be termed mucks contain from 15 to 50 per cent of 
vegetable matter, while those which would be called peats always 
contain over 50 per cent and usually from 70 to 75 per cent of vegetable 
matter. 
Drainage. — It is self-evident that the first need in the improvement 
of marsh lands is drainage. This has been briefly discussed in the 
chapter on that subject. In many cases the construction of good 
open ditches and surface drains is all that is necessary to permit 
cultivation of marshlands, but these must be made of large size. 
They should also be given sufficient depth to produce as much under- 
drainage as possible. Ditches from 6 to 8 feet in depth will drain 
land for a considerable distance on either side as well as carry very 
large volumes of flood water. It is important that such a ditch be 
given the proper cross section; that is, it must not be so wide at the 
bottom that the small stream of the drier portion of the year will 
shift back and forth over it, causing it to fill up. A narrow bottom 
will confine the smaller stream and cause it to keep the ditch clean. 
The slopes of the sides of the ditch should not be so steep that it 
will tend to cave in, and they should be grassed as far as possible. 
However, tile drainage is frequently necessary to permit the maximum 
use of marshlands. When peaty soils are to be tile drained it is 
frequently best to put in ditches where the tile lines are to be laid 
and allow the soil to settle for two or three years before the tiles are 
placed. If the ditches are then thoroughly cleaned out and the bottom 
fined, the tile can be placed and covered. In this way a line of tile 
will be much less apt to be distorted by irregular settling. 
Fertility. — Marsh soils have certain marked peculiarities in regard 
to fertility. Their high content of organic matter, of course, always 
