Canadian Forest Service Publications

Propriétés chimiques et physiques de la matière organique nondialysable extraite de quatre podzols du Québec. 1972. Gonzalez, A.; Hubert, G. Can. J. Soil Sci. 52 : 1-17.

Year: 1972

Issued by: Laurentian Forestry Centre

Catalog ID: 15307

Language: French

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The physical and chemical properties of non-dialyzable (> 48 A) humic and fulvic fractions of four podzols from the Province of Quebec were studied. Extraction was made with 0.1 M sodium pyrophosphate. Analysis of the fraction showed that, in spite of a prolonged dialysis, considerable quantities of metallic ions remained bound to compounds of high molecular weights. The humic fraction showed, in general, a carbon and nitrogen content sensibly more even than the fulvic fraction. In the spodic horizon, humic fractions have a very similar carbon content. It is also in this horizon that are found the highest percentages of iron and aluminium. The distribution of the principal nitrogen compounds in each fraction was studied after acid hydrolysis. A great similarity in the distribution of the nitrogen was found' independently of its origin (horizon or profile). It has not been possible to find a relation between profiles, from the study of acid groups (carboxylic or phenolic). Absorption spectra with ultraviolet, visible, and infrared radiations were studied. The characterization of a profile from optical properties of high molecular weight fractions was particularly difficult, considering the great similarity between observed spectra. Differences in iron bound to the fulvic fraction were observed by means of electrophoresis. The behaviour of the humic and fulvic fractions towards H+ and Ca2+ ions was also studied.