THE DRAINAGE OF FARM SOILS 231 



ten or fifteen feet of the surface, as is sometimes 

 the case, it may be practicable to sink a well 

 through the surface soil that holds the water, which 

 is usually clay or silt, into the more open subsoil 

 below. This well may be filled with stones to 

 within three or four feet of the surface, and the 

 balance with sand or soil; or it may be stoned up 

 and used as an outlet for tile drains. If expedient, 

 this water may be pumped out by a windmill and 

 used for irrigating surrounding fields. Water- 

 loving trees, as willow, larch and white maple, 

 will do much to drain these places in summer when 

 in full leaf, but unfortunately they are of no help 

 in early spring when such lands are most likely 

 to be wet. 



DRAINING LARGE SWAMPS AND MARSHES 



Aside from its value for improving farm soils 

 already under cultivation, and for bringing into 

 service meadows and small swamps, examples of 

 soil drainage on a large scale are becoming more 

 and more numerous. Shaler estimates that there 

 are over 100,000 square miles of swamp land in the 

 Eastern Atlantic Coast States alone which can be 

 reclaimed and made into profitable farming land 

 by drainage. It is estimated by one authority 

 that there are 600,000,000 acres of swamp land in 

 the United States. Some of these lands, which 

 include salt marshes and large fresh-water swamps 

 and meadows, are already being reclaimed. When 

 drained they usually become exceedingly pro- 

 ductive, partly because they contain so much 

 humus, and partly because they are perfectly sub- 

 watered at all times of the year. The great area 

 of lane 1 wrested from the sea during half a century 



