 |
| Titel |
Changes in the Mineral Assemblage of Paddy Soils upon Redox Cycles |
| VerfasserIn |
Vanessa Vogelsang, Sabine Fiedler, Reinhold Jahn |
| Konferenz |
EGU General Assembly 2010
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250039119
|
|
|
|
|
|
| Zusammenfassung |
| Rice is one of the major cereal crops of global agriculture. World wide more than 10% of the
arable land is used for rice production, mainly under temporarily waterlogged conditions.
This leads to distinct redox cycles, governing the biogeochemistry of paddy soils. Yet,
long-term effects of alternating redox conditions on the soil mineral matrix and properties are
still not fully understood. The objective of the project is to elucidate the processes of
mineral transformation as related to changing redox conditions and to time of rice
cultivation.
Long-term effects of rice cultivation on the mineral assemblage were studied along a
chronosequence of paddy soils (100, 700 and 2000a paddy soils) developed in comparable
parent material in the province of Zhejiang, China. Top soils were analysed for the mineral
assemblage and physicochemical properties using x-ray diffraction and chemical analyses,
respectively.
All studied clay fractions showed a similar clay mineral assemblage (illite, chlorite,
kaolinite, vermiculite, smectite). Differences among the paddy sites though could
not be related to the time of cultivation. The CECpot of the clay fraction slightly
increased from 100 to 2000 a paddy usage, which was partly attributed to a concurrent
increase of Corg. With age the Feo/Fed-ratio in both the Alp and Ardp-horizon
increased, with a maximum in the Ardp of the 2000 a paddy field. We conclude,
that due to an increasing number of redox-cycles, long-term cultivation enhances
the formation of microcrystalline Fe-hydroxides in the A-horizons of paddy soils.
Chronological changes in the clay mineral assemblage could not be observed in this study. |
|
|
|
|
|
|