EXPERIMENT STATION BULLETINS. 631 



at a low moisture content and in some soils, it is tremendously con- 

 centrated, and this concentration can be increased with the application 

 of soluble sails. (2). The concentration of the soil solution does not 

 remain constant but varies greatly with the moisture content, and the 

 amount and kind of soluble salts added. (3), The soil solution of 

 nonnal soils, in humid regions may never reach a saturation point, 

 in all the salts at least. (4). The magnitude of the concentration of 

 the soil solution is not tlie same for all soils but varies greatly with the 

 different soils. (5). The absorbtive power of the soils does not seem 

 to influence at all the concentration of the soil solution. Those soils 

 known to poswss the higliest absorbtive power generally contain a solu- 

 tion of very higli concentration, Avhile those that have a low absorbtive 

 power contain a low cencentration of solution. (6). The wilting of 

 plants at a low moisture content may not be entirely due to their in- 

 ability to obtain the remaining moisture in the soil, but also to the 

 plasmolytic effects of the high concentration of the soil solution. 



By means of the freezing point method the effect of application of 

 soluble salts upon the concentration of the soil solution in the soil, was 

 also studied. The compounds were added to the soil in solution in 

 n/100 strength and consisted of KCl, K..SO,, MgSO,. (NHJ.SO, 

 Ca(N03)„, NaNOs, K.HPO,, CaH,(POJo, and' Na.HPO^. The soils con- 

 sisted of washed quarts sand, two different kinds of silt loam, and clay, 

 and one kind of sandy loam, humus loam, peat, and kaolin. The re- 

 sults obtained in this study show that all these compounds have an 

 entirely different effect upon the concentration of the soil solution of 

 the different soils. In the case of the neutral salts the concentration of 

 the soil solution was increased from 20 to 100% of their strength em- 

 ployed, while in the case of the soluble phosphates the concentration 

 of the soil solution of all the soils except peat, quartz sand, and kaolin, 

 was extremely little, if any, increased. These results on the whole do 

 not confirm entirely the theories that the application of soluble salts, 

 even in small amounts, may not- increase the total concentration of the 

 soil solution. 



