OVER-IRRIGATION AND ALKALI 401 



moval of alkali, are not necessarily swampy; on the 

 contrary, they may be perfectly dry in their natural 

 condition. 



If underdrainage is used as the final remedy for alkali, 

 very heavy applications of water must be applied for 

 some time, until the alkali is thoroughly washed out and 

 carried off through the drains. This is a dangerous 

 procedure, for valuable plant-foods are taken out with the 

 alkali. The washing of the soil should be stopped, there- 

 fore, as soon as the main alkali condition has been cor- 

 rected. 



The possibility of removing alkali by underdrainage 

 has been well demonstrated by the Bureau of Soils of the 

 United States Department of Agriculture. The pioneer 

 experiment was made on land located west of Salt Lake 

 City, toward the Great Salt Lake. The farm, when 

 located, was covered with a glistening coat of white 

 alkali. The soils of the district are generally heavily 

 impregnated with alkali, chiefly common salt, from the 

 concentrated water of the Great Salt Lake, which has 

 either overflowed hi the past, or has moved through the 

 subsoil. From 2J^ to 5 per cent of alkali was found in the 

 soil at the time the experiments began, and ground water 

 stood about 4 feet from the surface. Tile pipe was laid 

 in the usual manner, at a cost of about $16 an acre. In 

 1903, the year after the laying of the tile, the land was 

 thoroughly flooded, and from August, 1904, it was again 

 flooded thoroughly, at various intervals, until 1906, when 

 the land was returned hi a good agricultural condition to 

 the owner. Since that time a thrifty crop of alfalfa has 

 grown upon it, as proof that the alkali condition has been 

 permanently corrected. From September, 1902, to Octo- 

 ber, 1904, the water added was equal to a little more 

 z 



