EXPERIMENT STATION BULLETINS. 



643 



ments were conducted from July 10 to September 4. The freezing point 

 lowerings of the samples of soil taken from the treated and untreated 

 soil are shown in table 6. 



TABLE 6.— MOVEMENT OF SALT IN MEDIUM SAND. 



Some of the salt that was placed six inches from the surface accumu- 

 lated in the second la^^er of soil but not in the surface. Whereas the 

 change in concentration of the soil solution was inappreciable three 

 inches from the surface in the tube in which the salt was placed twelve 

 inches from the surface. In the former case the soil became dry on the 

 surface before the salt reached this point and in the latter the dry layer 

 or mulch was formed to a depth of about four inches, thus preventing 

 higher translocation of the soluble material. 



The effect of the depth to water table upon the salt content of soils 

 has been investigated in the laboratory . Four cylinders were filled with 

 each of the soil classes studied, placed in larger containers which were 

 filled with water to sufficient height to bring the water table to the surface 

 of the soil. After the water table had reached the surface two grains 

 of sodium chloride were added to two of the containers. After a period 

 of forty-seven days the treated and untreated soils were sampled at 

 different depths and the freezing point lowerings determined. The rate 

 of evaporation was high inasmuch as the experiments were run from 

 July 19 to September 4, the containers being exposed to sunshine and to 

 wind movements. 



