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Geochemical Modeling of Zinc Bioavailability for Rice
Author(s) -
Gao Xiaopeng,
Schröder Thomas J.,
Hoffland Ellis,
Zou Chunqin,
Zhang Fusuo,
Zee Sjoerd E.A.T.M.
Publication year - 2010
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2008.0060
Subject(s) - rhizosphere , bioavailability , anaerobic exercise , chemistry , soil water , environmental chemistry , oryza sativa , agronomy , soil ph , zinc , bulk soil , soil science , soil organic matter , environmental science , biology , physiology , bioinformatics , biochemistry , genetics , organic chemistry , bacteria , gene
The transition from anaerobic to aerobic rice ( Oryza sativa L.) cultivation has been reported to decrease Zn bioavailability. To determine and understand the differences in plant Zn uptake between anaerobic and aerobic rice cultivation systems, a field plot experiment was conducted with direct‐seeded rice grown on a low‐Zn soil under both anaerobic and aerobic conditions. Results showed that the mass fraction of Zn in shoots and Zn uptake of plants in the aerobic field was significantly lower than in the anaerobic field. Visual Zn deficiency symptoms as whitish‐brown necrotic patches on leaves were more severe on plants grown in aerobic soils than plants in anaerobic soils, indicating reduced Zn bioavailability. To determine whether the underlying causes could be of a geochemical nature, a controlled soil incubation experiment was done. Using a fully parameterized model, we found that the difference in plant Zn uptake between the two cultivation systems was small compared with that predicted by geochemical modeling, assuming Zn uptake is controlled by the soluble fraction in the soil. Whereas individual effects of soil factors (e.g., pH) were demonstrated to cause large variations in Zn concentration, only about a 15% difference in plant Zn uptake was observed. This large discrepancy reveals that the consideration of separate soil chemical processes, instead of their integrated assessment, may be inappropriate. We speculated that the discrepancy could also be associated with the chemical conditions in the rhizosphere, where the local acidity, dissolved organic C, and redox conditions may deviate significantly from the bulk soil on which the geochemical analysis was based.