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 tUes are 

 placed. If the ditches are then thoroughly cleaned out and the bottom 

 lined, the tile can be placed and covered. In this way a line of tile 

 will be much less apt to be distorted by irregular setthng. 

 • Fertility. — ^Marsh soils have certain marked peculiarities in regard 

 to fertility. Their high content of organic matter, of course, always 



