THE USE OF pH-DEPENDENT CATION-EXCHANGE CAPACITY FOR CHARACTERIZING THE B HORIZONS OF BRUNISOLIC AND PODZOLIC SOILS

Abstract

A study was made of the pH-dependent C.E.C. as a means of characterizing and differentiating the B horizons of Brunisolic and Podzolic soils. The pH values were measured in 0.01 M CaCl2 after which the soils were extracted with Nacl to determine the percentage base saturation and sum of exchangeable cations. The total C.E.C. values were determined with Ca(OAc)2 + CaCl2 at pH 7 of the untreated soil and of the soils after H2O2 treatment, after extraction with acid ammonium oxalate, and after heating at 200 °C in an atmosphere of N2. The pH-dependent C.E.C. represented by the difference between the C.E.C value determined with Ca(OAc)2 + CaCl2 and the sum of cations extracted with NaCl was found to be small for the B horizons of Brown Forest and Brown Wooded soils. The B horizons of Podzol, Humic Podzol, Acid Brown Wooded, Concretionary Brown, and some Acid Brown Forest soils had high pH-dependent C.E.C. The horizons with high pH-dependent C.E.C. contained significant quantities of amorphous sesquioxide–organic complexes as shown by their relatively high organic matter and free sesquioxide contents and by their exchange properties. The pH-dependent charge appeared to be as effective a primary chemical means of characterizing horizons with spodic properties as were techniques based on the effects of free oxide extraction or heating in N2 on the exchange capacity.

Etude Sur La Valeur Des Criteres Chimiques Proposes Par La Commission Pedologique Du Canada Pour La Classification Taxonomique Des Sols Du Quebec

“…d6termin6es selon les m6thodes de Clark (1965) et Clark et al (1966). L'analyse granulom6trique a 6t6 effectu6e selon la m6thode h la pipette.…”

Influence of Basic Material on Soil Genesis in the Thetford–black Lake Area, Province of Quebec

“…Sampling sites were chosen to provide coverage of the different parent materia'ls as follows: (l) The till derived from two difierent formations (Cooke 1938 Clark (1965) and Clark et al (1966).…”