098 STATE BOARD OF AGRICULTURE. 



the difference in ionization of the different compounds and the con- 

 sequent dillerence in the freezing point depression, it does not seem 

 possible that these processes conhl be going on without causing a change 

 or fluctuation in the lowering of the freezing point. Wherever a change 

 occurs the method detects it, as in the case where a reverse action takes 

 place. 



To conclude then, it seems probable that the solubility of the soils 

 under consideration would continue much further than it did, but on 

 account of some opposing factors it comes to a standstill after a certain 

 length of time. Some of the opposing factors are the living orgjinisnis 

 in the soil, the concentration of the solution itself, and the adsorptive 

 power of the soil. 



Finally, it must be emphasized that the above and other factors do 

 not diminish the fundamental importance of the experimental results 

 of this investigation from both the practical and scientific standpoints. 

 In the first place, the most important fundamental principle on the rate 

 and solubility from both the practical and scientific standpoint are estab- 

 lished at the beginning and especially at the first or second day of the 

 experiment, and the factors mentioned above do not come into play for 

 a long time ; and in the second place tlie method employed in obtaining 

 these experimental results is essential and desirable for a complete and 

 comprehensive study of the rate and extent of solubility of soils both 

 treated and untreated. As will be seen subsequently this method is 

 checked by a method which aims to simulate field conditions, and thus 

 affords a comparison in the results between the two methods. 



From the practical standpoint the rate and extent of solubility in the 

 first and second day are the most important because they show the 

 possible rate and amount of material which goes in solution for the use 

 of the plant. During this time there was no biological action in these 

 soils which affected the results. 



Rate and Extent of Solubility of Soils Treated with a Combination of 

 Salts and then Washed Until the Free Soluble Salts Were Eliminated. 

 Ratio of Soil to Water was about 1 to .7 and Mixture JMaintained at 

 Room Temperature. 



In the preceding study only single salts were employed. In the present 

 study a combination of salts was employed. This combination of salts 

 ccmiprised all the single salts used previously, namely, Ca(N03)2> NaNO,, 

 KNO3, KCl, K,SO„ (NH,).,SO„ MgSO,, CaHJPOJ,, KH3PO,, and 

 NaCoHgOa. The strength of this solution was tenth normal, the same 

 as of the single salt solutions. The soils were exactly the same as before. 

 The procedure of treating the soils and measuring the rate and extent 

 of solubility was also the same as in the preceding study. The results 

 obtained are presented in table 8. This table contains the rate and extent 

 of solubility as indicated by the freezing point depressions of the treated 

 and untreated soils. 



