Biogeochemical mechanisms of C and P cycles in paddy driven by the FeIII-FeII redox wheel in dynamic redox environment
Final Report Abstract
Soil flooding or drying leads to the rapid onset of reducing or oxidizing conditions. The changing redox conditions significantly influence the characteristics of redox-sensitive iron (Fe) minerals, which in turn affect the cycling of essential nutrients, e.g. P and C, in the soils through the sorption/desorption, and (co)precipitation/dissolution processes. The overarching aim of the project was to determine the interrelations between redox-sensitive ferric and ferrous iron minerals with the cycling of the P and C in paddy soil. The specific original aim of the individual WP conducted at the University of Göttingen (this report) was (i) to investigate the quantitative contribution of the reductive dissolution of ferric Fe-bound inorganic P (Fe–P) to the demands of rice plants and microorganisms by means of 32P isotope labelling. Additionally, the WP was extended (ii) to address the effects of the reductive dissolution of Fe(III) on rice root growth and (iii) to explore the effects of continuously flooded or alternate wetting and drying water regimes on the dynamics of P release from the Fe-P and wheat straw (organic P source). In a series of experiments on rice plants grown in chinese paddy soil we quantified contribution of Fe-derived P for plant and microbial uptake using 32P-labeled ferrihydrite supplied either in polyamide mesh bags to prevent roots but not microorganisms from direct Fe-P mobilization, or directly mixed with soil to enable roots and microorganisms access to the Fe-P. A novel in-situ phosphor-imaging approach under flooding was developed to estimate P uptake by rice roots released from Fe-P dissolution. Dual P-labelling with 32P-ferrihydrite and 33P-wheat straw was applied for the first time to estimate the quantitative contributions of the Fe-P dissolution and organic P mineralization to the P nutrition of rice plants and microorganisms under flooded and alternate wetting-drying water regimes. The results of the experiments demonstrated Fe-P and wheat straw can serve as relevant P sources for rice production and could compensate up to 16% and 20% of plant P demand, respectively. High C availability for microorganisms in the rhizosphere intensified P mobilization. Continuous flooding increased the contributions of P released from Fe-P dissolution and wheat straw decomposition to P nutrition compared to alternate wetting and drying regime. Microorganisms were more competitive for organic P than rice plants, and rice plants outcompeted microorganisms for P released from the reductive dissolution of Fe-P. In conclusion, although the P amount by Fe-P dissolution and wheat straw decomposition did not fully meet the P requirements of both rice plants and microorganisms, phosphate fertilization strategies should be adapted to the rates of P mobilization from Fe (oxyhydr)oxides and straw under different water regimes. Rice varieties with extended crown roots will increase P uptake when P is limiting in paddy soils.
Publications
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an ferric iron reduction in paddy soils compensate phosphorus limitation of rice plants and microorganisms? EGU22-7241, EGU General Assembly 2022
Wang, C.Q.; Dippold, M.A.; Guggenberger, G. & Dorodnikov, M.
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Can the reductive dissolution of ferric iron in paddy soils compensate phosphorus limitation of rice plants and microorganisms?. Soil Biology and Biochemistry, 168, 108653.
Wang, Chaoqun; Thielemann, Lukas; Dippold, Michaela A.; Guggenberger, Georg; Kuzyakov, Yakov; Banfield, Callum C.; Ge, Tida; Guenther, Stephanie; Bork, Patrick; Horn, Marcus A. & Dorodnikov, Maxim
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Microbial iron reduction compensates for phosphorus limitation in paddy soils. Science of The Total Environment, 837, 155810.
Wang, Chaoqun; Thielemann, Lukas; Dippold, Michaela A.; Guggenberger, Georg; Kuzyakov, Yakov; Banfield, Callum C.; Ge, Tida; Guenther, Stephanie; Bork, Patrick; Horn, Marcus A. & Dorodnikov, Maxim
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Reductive dissolution of ferric iron changes rice root morphology in phosphate-deficient paddy soils. DBG Annual Meeting 2022
Wang, C.Q.; Dippold, M.A.; Guggenberger, G.; Kuzyakov, Y. & Dorodnikov, M.
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Reductive dissolution of iron phosphate modifies rice root morphology in phosphorus-deficient paddy soils. Soil Biology and Biochemistry, 177, 108904.
Wang, Chaoqun; Thielemann, Lukas; Dippold, Michaela A.; Guggenberger, Georg; Kuzyakov, Yakov; Banfield, Callum C.; Ge, Tida; Guenther, Stephanie & Dorodnikov, Maxim
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The wetter the better: Rice outcompetes microorganisms for iron-oxide bound P under continuous flooding, DBG Annual Meeting 2023
Dorodnikov, M.; Wang, C.Q.; Dippold, M.A.; Guggenberger, G. & Kuzyakov, Y.
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The wetter the better? Preferences in plant-microbial competition for phosphorus sources in rice cultivation under contrasting irrigation. Soil Biology and Biochemistry, 191, 109339.
Wang, Chaoqun; Dippold, Michaela A.; Guggenberger, Georg; Kuzyakov, Yakov; Guenther, Stephanie & Dorodnikov, Maxim
