EXPERIMENT STATION BULLETINS. 



333 



TABLE 10.— Fixation from Ca{CiHz02)i and KCiHiOi. 

 Calcium added 0.466 gm. Potassium added 0.3981 gm. 



Excepting calcium fixed by the medium sands, the alkaline soils fixed 

 more calcium and potassium and liberated more calcium and magnesium 

 than the corresponding members of each class. The exchange, however, 

 was not in equivalent proportions thereby agreeing with results from the 

 phosphate treatments. Quantities of calcium and magnesium found in the 

 extracts agreed favorably with those found in the case of the neiitral salt 

 treatments, particularly KCl. E\idently calcium and potassium were fixed 

 and an equilibrium set up between certain soil elements and the acetate 

 ion, the acetates formed being soluble in water. It may also be observed 

 from results given in Table 10 that the KOH titration on the soil extracts 

 with phenolphthalein as indicator was not a measure of the calcium or potas- 

 sium fixed by the soils, but an approximate measure of conditions in the 

 extract; i. e. the closer the equivalent of acetate-ion to potassium fixed by 

 the soils, or acetate-ion set free, agree to those of calcium and magnesium 

 found in the extracts less KOH is required to neutralize the extracts. This 

 relationship is not so apparent in case of the Ca(C2H302)2 treatments. While 

 these results are not definite they nuay be considered as indications of the 

 true state of affairs in this connection. 



Results Obtained from Treating the Soils with K2C2O4 and FeCls 



