1. Dynamic influence of S fertilizer on Cu bioavailability in rice (Oryza sativa L.) rhizosphere soil during the whole life cycle of rice plants.
- Author
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Sun, Lijuan, Liu, Qinglin, Xue, Yong, Xu, Chen, Peng, Cheng, Yuan, Xiaofeng, and Shi, Jiyan
- Subjects
BIOAVAILABILITY ,RHIZOSPHERE ,PADDY fields - Abstract
Purpose: Addition of S fertilizer influences the behavior of metals in soil, the mechanism of which has not been extensively studied to date. We explored the dynamic influence of S fertilizer (S
0 and Na2 SO4 ) applied in paddy soils on Cu bioavailability in rice rhizosphere soil during the life cycle of rice plants.Materials and methods: Through a microcosm experiment, the speciation of Cu and S in rhizosphere soil was explored by traditional chemical extraction methods and advanced synchrotron-based X-ray absorption near-edge spectroscopy (XANES) techniques.Results and discussion: In the vegetative stages of rice plants, sulfur fertilization increased the concentration of bioavailable Cu, as well as the dissolved organic carbon (DOC) concentration in rhizosphere soil. Meanwhile, a higher proportion of Cu-humic substances was found in soil treated with S than that in control soil. However, extended flooding conditions led to the reduction of S fertilizer to sulfide, which provided the substrate for Cu2 S formation. Thus, in the reproductive stages of rice plants, a higher proportion of Cu2 S formation from +S treatments led to a relatively lower concentration of bioavailable Cu in rice rhizosphere soil than in control soil.Conclusions: The influence of S fertilizer on Cu bioavailability depended on the growth stage of rice plants. Both the DOC and redox potential (Eh) were changed by S fertilization in paddy soils and are critical factors that control Cu speciation in rice rhizosphere soil. [ABSTRACT FROM AUTHOR]- Published
- 2019
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