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Paddy soil biogeochemical processes under water-saving irrigation

Heleen Deroo (UGent)
(2021)
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(UGent) and (UGent)
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Abstract
To cope with climate change, the use of water-saving irrigation practices in rice production is increasingly promoted, instead of the traditional practice of continuous flooding. However, it is unclear how the periodic introduction of oxygen during drying events impacts some fundamental biogeochemical processes in paddy soils because of the difficulty to quantify them. This knowledge gap actually complicates the development of mechanistic biogeochemical models, which are key for the prediction of paddy soil nutrient dynamics over a range of edaphic, agronomic and climatic settings. We experimentally investigated the effect of water-saving irrigation management on three prominent but understudied carbon and nitrogen transformations in paddy soil by means of stable isotopes, in an effort to improve their implementation in soil models. In particular, we assessed the oxidation of methane (CH4), the decomposition of soil organic carbon (SOC) after the incorporation organic residues, and the fixation and defixation of ammonium (NH4+) in clay interlayers, always as a function of irrigation management. Then, we validated the soil model DNDC-Rice for its ability to simulate the effects of drying events on various processes that are relevant for paddy soil C and N cycling. As it turns out, the influence of irrigation management on equilibrium amounts of clay-fixed NH4+ in paddy soil is rather limited, while the adoption of water-saving irrigation practices has the potential to stimulate CH4 oxidation and to restrict the enhancement of native SOC dissolution caused by the amendment of paddy soil with organic residues. With a well-considered experimental set-up, stable isotopes appear to be a promising tool to quantify gross nutrient transformations in paddy soil. Lastly, there is room for improvement in the current implementation of some processes in DNDC-Rice, regardless of the irrigation regime.
Keywords
Paddy soil, Water-saving irrigation, Soil biogeochemistry, Stable isotopes

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Citation

Please use this url to cite or link to this publication:

MLA
Deroo, Heleen. Paddy Soil Biogeochemical Processes under Water-Saving Irrigation. Ghent University. Faculty of Bioscience Engineering, 2021.
APA
Deroo, H. (2021). Paddy soil biogeochemical processes under water-saving irrigation. Ghent University. Faculty of Bioscience Engineering, Ghent, Belgium.
Chicago author-date
Deroo, Heleen. 2021. “Paddy Soil Biogeochemical Processes under Water-Saving Irrigation.” Ghent, Belgium: Ghent University. Faculty of Bioscience Engineering.
Chicago author-date (all authors)
Deroo, Heleen. 2021. “Paddy Soil Biogeochemical Processes under Water-Saving Irrigation.” Ghent, Belgium: Ghent University. Faculty of Bioscience Engineering.
Vancouver
1.
Deroo H. Paddy soil biogeochemical processes under water-saving irrigation. [Ghent, Belgium]: Ghent University. Faculty of Bioscience Engineering; 2021.
IEEE
[1]
H. Deroo, “Paddy soil biogeochemical processes under water-saving irrigation,” Ghent University. Faculty of Bioscience Engineering, Ghent, Belgium, 2021.
@phdthesis{8723193,
  abstract     = {{To cope with climate change, the use of water-saving irrigation practices in rice production is increasingly promoted, instead of the traditional practice of continuous flooding. However, it is unclear how the periodic introduction of oxygen during drying events impacts some fundamental biogeochemical processes in paddy soils because of the difficulty to quantify them. This knowledge gap actually complicates the development of mechanistic biogeochemical models, which are key for the prediction of paddy soil nutrient dynamics over a range of edaphic, agronomic and climatic settings. We experimentally investigated the effect of water-saving irrigation management on three prominent but understudied carbon and nitrogen transformations in paddy soil by means of stable isotopes, in an effort to improve their implementation in soil models. In particular, we assessed the oxidation of methane (CH4), the decomposition of soil organic carbon (SOC) after the incorporation organic residues, and the fixation and defixation of ammonium (NH4+) in clay interlayers, always as a function of irrigation management. Then, we validated the soil model DNDC-Rice for its ability to simulate the effects of drying events on various processes that are relevant for paddy soil C and N cycling. As it turns out, the influence of irrigation management on equilibrium amounts of clay-fixed NH4+ in paddy soil is rather limited, while the adoption of water-saving irrigation practices has the potential to stimulate CH4 oxidation and to restrict the enhancement of native SOC dissolution caused by the amendment of paddy soil with organic residues. With a well-considered experimental set-up, stable isotopes appear to be a promising tool to quantify gross nutrient transformations in paddy soil. Lastly, there is room for improvement in the current implementation of some processes in DNDC-Rice, regardless of the irrigation regime.}},
  author       = {{Deroo, Heleen}},
  isbn         = {{9789463574457}},
  keywords     = {{Paddy soil,Water-saving irrigation,Soil biogeochemistry,Stable isotopes}},
  language     = {{eng}},
  pages        = {{XVIII, 180}},
  publisher    = {{Ghent University. Faculty of Bioscience Engineering}},
  school       = {{Ghent University}},
  title        = {{Paddy soil biogeochemical processes under water-saving irrigation}},
  year         = {{2021}},
}