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Changes in magnetic properties and their pedogenetic implications for paddy soil chronosequences from different parent materials in s outh C hina
Author(s) -
Han G.Z.,
Zhang G.L.
Publication year - 2013
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/ejss.12050
Subject(s) - pedogenesis , silt , ferrimagnetism , clay minerals , soil science , soil water , magnetism , remanence , geology , chemistry , mineralogy , environmental chemistry , magnetization , geomorphology , magnetic field , physics , quantum mechanics
Summary It remains unknown whether there is a consistent relationship between magnetism dynamics and pedogenesis for paddy soils. In this study, three paddy soil chronosequences, derived from purple sandy shale ( PS ), Quaternary red clay ( RC ) and red sandstone ( RS ) in the hilly regions of south China, were studied to identify changes in magnetism during soil development and to understand their implications for pedogenesis. The results show that magnetic susceptibility ( MS ) and soft isothermal remanent magnetization ( IRM s ) simultaneously decreased to extremely small values in the anthrostagnic epipedons during the initial stages of cultivation. In contrast, this decrease was limited in the hydragric horizons of the young paddy soils and even increased in some. These changes suggest that MS and IRM s can be enhanced by the oxidation of Fe 2+ in acid paddy soils (between pH 5 and 6) or be depressed by anaerobic transformations of ferrimagnetic minerals. The main influence on magnetic properties was time duration and especially reducing degree of artificial submergence, while parent materials played a supportive role. Magnetic enrichments generally occurred in the clay fraction. Ferrimagnetic clay minerals were more easily altered than minerals in the silt and sand fractions. The study also shows that there was no fixed pattern in the relationship between magnetism and paddy pedogenesis and magnetic properties should be used with care when applying them to environments in which redox processes occur.