In irrigated districts, where excessive quantities of water are used, there is usually an accumulation of alkali salts in the soils of the lower lands. These salts are probably dissolved from the soils through which the percolating waters pass and are carried along until the water comes to the surface and is evaporated, when the salts are deposited as a crust at the surface. Many of the most fertile soils of the arid regions have been ruined by the bringing to the surface of soluble salts in such large quantities that the growth of crops is prohibited. The rapidity with which salts can be removed by water is also an important question in the reclamation of alkali soils by drainage.
In order to determine more exactly the movement of salts with water through the soil, a number of experiments were made using small sections of soil containing various quantities of soluble salts. Water was passed through these soils horizontally and vertically and the salts later determined in different parts of the soil. While these sections of soil do not exactly duplicate field conditions, they probably, on a small scale, obey the laws which operate when water passes through field soils.
Harris, F. S., "Bulletin No. 139 - The Movement of Soluble Salts with the Soil Moisture" (1915). UAES Bulletins. Paper 90.