710 



STATE BOARD OF AGRICULTURE. 



TABLE 21.— KATE AND EXTENT OP SOLUBILITY OF SAND TREATED WITH ACIDS 

 AND THEN WASHED UNTIL ALL FREE SOLUBLE ACIDS WHERE ELIMINATED. 

 RATIO OF SOIL TO WATER WAS 1 TO .4 AND MIXTURE MAINTAINED AT ROOM 

 TEMPERATURE. FIGURES REPRESEN8 FREEZING POINT DEPRESSION. 



The above data show that in the case of the inorganic acids the rate 

 of solubility' is rather rapid, equilibrium being reached in many cases 

 in the first three or four days, and the extent of solubility is quite small, 

 the freezing point depression not exceeding .025° C in the heavy type of 

 soils, and about 010 °C in the sand, at the end of about 80 daj'S. The 

 extent of solubility in the case of phosphoric acid treatment is slightly 

 greater than that of the other inorganic acid treatments. In the case 

 of the organic acids the results are somewhat inconsistent but they 

 indicate that the rate of solubility is also rather rapid but tlie process 

 goes on for a much longer time and the extent of solubility is very large 

 and especially in some cases. Thus, in table 17 the depression rose in 

 the case of H^C^O, from .010° to .112 °C in 55 days. After a certain 

 length of time the depression of some of these organic acid treatments 

 begins to decrease, indicating that the material is going out of solution. 

 This reverse action is similar to that in the case of the (NH4)2S04 treat- 

 ment. 



From various standpoints these results with the various acids are very 

 interesting and very instructive. 



Rate and Extent of Solubility of Natural or Untreated Soils Which 

 Were Previously Washed Until All Free Soluble Salts Were Eliminated, 

 Ratio of Soil to Water Was About 1 to .7 and Mixture Maintained at 

 Room Temperature. 



Having established certain fundamental principles with the salt, fer- 

 tilizer and acid treatments on the rate and extent- of solubility of soils, 

 the investigation on the rate and extent of solubility of natural or 

 untreated soils is now in order. 



This part of the investigation comprised a great number of soils, 

 coming from several different states, and including many different types 

 and nearly all the various classes. It was tlie purpose in this research 

 to study the effect of type, class, origin, fineness of particles, organic 

 matter content and many other factors upon the rate and extent of solu- 

 bility of soils. The procedure of preparing the soils and measuring the 

 rate and extent of solubility were the same as before, namely, the soils 



