THE MOVEMENT OF SOLUBLE SALTS WITH 

 THE SOIL MOISTURE. 



By 

 F. S. HARRIS 



1. Introduction. 



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 sur- 

 face. 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 hori- 

 zontally and vertically and the salts later determined in dif- 

 ferent 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. 



2. Horizontal Movement of Salts. 



Special tanks were arranged to study the horizontal move- 

 ment of salts through the soil. These were made of galvanized 

 iron and were six feet long, one foot wide and four inches deep. 

 Soil was placed in the tanks to a depth of three inches and the 

 entire surface sealed over with paraffined paper, except a square 

 foot at one end which was left uncovered. This made five 

 square feet of the soil covered, and one square foot open for the 

 free evaporation 'of water. 



On the end of the tank opposite the uncovered portion, was 

 an opening into the tank through which water was poured. The 

 water entering this opening passed horizontally through the 

 soil to the other end, there being evaporated from the square 



