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Metal‐humus complexes in A horizons of Thai and Korean red and yellow soils
Author(s) -
VIRAKORNPHANICH P.,
WADA S.I.,
WADA K.
Publication year - 1988
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.1365-2389.1988.tb01237.x
Subject(s) - inceptisol , soil water , humus , ultisol , chemistry , andosol , oxisol , montmorillonite , total organic carbon , clay minerals , environmental chemistry , soil science , mineralogy , geology , organic chemistry
SUMMARY Carbon, Al and Fe (C pyr , Al pyr and Fe pyr ) were extracted with 0.1 m Na 4 P 2 O 7 from 26 A horizon samples of tropical Thai and temperate Korean soils (Ultisols, Alfisols, Oxisols and Inceptisols). The soils, except for one Thai Inceptisol, had similar total C (0.35–3.29%) and C pyr /total C ratios (0.20–0.41). There were approximately linear relationships between total C or C pyr and clay content; two groups of soils gave different linear relationships. A curvilinear relationship between C pyr and (Al + Fe) pyr (milli‐atom kg −1 ) that can be approximated by an equation: C pyr = 53 (Al pyr + Fe pyr ) 1/2 – 24 was also found for most Thai and Korean soils. The above relationships indicated that total C and C pyr would be close to zero at zero clay or zero (Al + Fe) pyr . It was inferred that clay‐humus interaction has a primary importance in the determination of humus content in red and yellow soils in tropical and temperate regions and that the main role of clay is to supply Al and Fe that complex and stabilize humus against microbial degradation.