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SIZE FRACTIONATION, DISSOLUTION ANALYSIS, AND INFRA‐RED SPECTROSCOPY OF HUMUS COMPLEXES IN ANDO SOILS
Author(s) -
HIGASHI TERUO,
WADA KOJI
Publication year - 1977
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1977.tb02272.x
Subject(s) - allophane , humus , imogolite , silt , chemistry , podzol , dissolution , soil water , fractionation , mineralogy , clay minerals , geology , soil science , chromatography , organic chemistry , paleontology
Summary Eight samples of Ando soil A 1 and buried A 1 horizons of different ages were fractionated into clay‐, silt‐, and sand‐size separates, and the yields and carbon contents of these separates were determined. The clay‐size separates were subjected to two series of successive extractions, 1) 0.1 M Na 4 P 2 O 7 /2% Na 2 CO 3 /0.5 M NaOH and 2) dithionite‐citrate/2% Na 2 CO 3 /0.5 M NaOH; and to difference infra‐red spectroscopy for identification of the extracted constituents. The result indicated that humus evolves from forms with a very low complexing ability for Al and Fe into forms that complex Al and Fe in the A 1 horizon, and that humus further interacts with allophane‐like constituents, allophane and imogolite in the buried A 1 horizon. These reactions between humus and inorganic constituents result in formation of silt‐ and sand‐size aggregates which are stable to sonic wave treatment, but are broken down into finer particles upon boiling with H 2 O 2 .