388 BOAKD OF AGRICULTURE. [Pub. Doc. 



exceeds seven feet the conditions are tolerably simple. It 

 is, in the first place, necessary to exclude the salt water and 

 to permit the egress of that which comes from the land by 

 means of a sufficient dike or dam, provided with flood gates 

 which close at the time of the incoming tide and open during 

 the later stages of the reflux. The site and conditions of 

 this dam afford engineering problems which have to be dealt 

 with according to the local conditions. In arranging this 

 barrier it is necessary to provide for the storage on the land 

 side of the water which may be brought down by the rivers 

 during the time when the flood gates are closed, in order to 

 prevent the inflow of the sea water. This can generally be 

 accomplished by placing the dam in such a position that 

 there is a large sectional area of creek channels enclosed in 

 the reclaimed district. The next step after the outer dike 

 is constructed is to ditch the ground so that open trenches 

 may be provided in such manner that the soil water is main- 

 tained at a sufficient depth below the surface. In general it 

 is desirable to have these channels not more than a hundred 

 feet apart. Although it is best that they should be open 

 ways until the first desiccation of the soil is accomplished, 

 they may afterwards be brought into the condition of ordi- 

 nary tile drains. Before or after the drain ways are cut the 

 surface soil to the depth of the fibrous peat should be over- 

 turned by the plough, in order to kill the natural growth 

 and to favor the leaching out of the salt from the superficial 

 parts of the marsh. It commonly requires about two years 

 to secure a sufficient removal or decomposition of the salt to 

 fit the soil for crops ; but after a year the fields, if the arti- 

 ficial drainage be made deep, may be planted with rye, which 

 will sometimes yield a crop. It often happens that an 

 incrustation of salt forms on the surface of the ground, but 

 this is readily destroyed by ploughing. 



For the first few years after the tillage of these reclaimed 

 soils of the marshes is undertaken, culture is made difficult 

 by the presence of the fibrous peat, which is slow to decay, 

 and by the excess of salt. Under favorable conditions, how- 

 ever, these fields can be brought into an excellent state 

 within three years from the time when the sea water is 

 excluded from them. At the outset it is best to maintain 



