THE PHYSICAL ACTION OF LIME ON CLAY SOILS 



23 



HYGRO-INTERSTITIAL MOISTURE STUDIES 



In view of the unsatisfactory results obtained by the Rodewald-Mit- 

 scherlich method, it seemed desirable to revert to the type of procedure 

 used in the beginning. The writer has been fortunate in obtaining a 

 method which is free from errors due to condensation, and is at the same 

 time exceedingly accurate. Preliminary work with this method indicates 

 that liming seems to have no significant effect on hygro-interstitial mois- 

 ture in amounts equivalent to the lime requirements of the soil. Exces- 

 sive applications decrease the value. 



OXIDATION STUDIES. 



The work was conducted as follows : The equivalents of four grams of 

 soil were weighed into 8-oz. bottles, and 50 cc. of phenolphthalein solu- 

 tion added. After oxidation had progressed satisfactorily, the solutions 

 were cleared of humus and suspended matter with hot alum solution, an 

 aliquot made alkaline with ammonia, and read against a standard. The 

 results are as follows: (Each figure is the average of three determina- 

 tions. The probable error is approximately a plus or minus two). 



OXIDATION OF PHENOLPHTHALEIN BY SOILS TREATED FOR 100 DAYS 



OXIDATION OF PHENOLPHTHALEIN BY SOILS TREATED FOR 225 DAYS 



The data for the soil run 225 days goes just about as we would like it 

 to go. We get the greater oxidation in soils in which we would expect 

 the greater internal surface, and we obtain a decrease in oxidation with 

 increasing applications of lime. The results for the soils run 100 days 

 are not quite so satisfactory. It may be that in certain cases an exchange 

 of bases results in the release of substances which catalyze the reaction. 



