332 



STATE BOARD OF AGRICULTURE. 



Table 9. — Fixation from KiPOi and CaiHiPOCit H2O. 



Both members of each salt were fixed by the soils but not in chemically 

 equivalent quantities. The magnitude and order of the calcium fixation 

 did not differ materially from that determined in some of the preceding 

 experiments with other calcium salts. The fixation of potassium, however, 

 was considerably increased, but this quantity fixed was greater in case of 

 the alkaline soils except the alkaline clay loam. Evidently the soil factors 

 that determined the clegree of fixation of potassium and calcium ions from 

 neutral salts and hydroxides were operating also in the experiment under 

 consideration. After treating the soils with HCl and washing wdth distilled 

 water in the same manner as was previously described the fixation of PO4 

 was reduced but comparatively large quantities of PO4 were fixed. The 

 medium sand soils, acid sandy loam and silt loam fixed a greater equivalent 

 of PO4 than potassium. On the other hand, the alkaline sandy loam and 

 the clay loam soils fixed greater equivalents of potassium than PO4. Quan- 

 tities of calcium liberated by the K3PO4 treatments were very small except 

 in case of the clay loam soils. 



The alkaline soils, except the medium sand, fixed more calcium from 

 Ca(H2P04)2 than the acid soils of similar classes. Irregularities were also 

 apparent between the fixation of calcium and PO4 but these irregularities 

 are not consistent with those observed with the K3PO4 treatments A greater 

 quantity of PO4 was used in the Ca(H2P04)2 treatments and may have 

 changed conditions to some extent. The above stated results, however, 

 point strongly to the conclusion that fixation of PO4 in the experiment was not 

 dependent upon the same soil factors as fixation of potassium or calcium and 

 was independent of the quantities of potassium or calcium fixed, as shown })y 

 the unsatisfied equivalents. The phosphates form insoluble salts with cal- 

 cium and magnesium, however, and are fixed by soils. 



Results From Ca(C2H302)2 and KC2H3O2 Treatments 



Fixation from calcium and potassium acetates was next studied. The 

 effects of Ca(C2H302) were desired and KC2H30i was compared with the 

 calcium compound because it is a salt of the same class. Results are given 

 in Table 10. 



