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@PHDTHESIS{Schrder:151172,
      author       = {Schröder, Natalie},
      title        = {{T}hree-dimensional {S}olute {T}ransport {M}odeling in
                      {C}oupled {S}oil and {P}lant {R}oot {S}ystems},
      volume       = {22},
      school       = {Université catholique de Louvain (UCL), Louvain-La-Neuve},
      type         = {Dr.},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {FZJ-2014-01171},
      isbn         = {978-3-89336-923-2},
      series       = {Schriften des Forschungszentrums Jülich. IAS Series},
      pages        = {xii, 126 S.},
      year         = {2014},
      note         = {Université catholique de Louvain (UCL), Louvain-La-Neuve,
                      Diss., 2013},
      abstract     = {Many environmental and agricultural challenges rely on the
                      proper understanding of water flow and solute transport in
                      soils, for example the carbon cycle, crop growth, irrigation
                      scheduling or fate of pollutants in subsoil. Current
                      modeling approaches typically simulate plant uptake via
                      empirical approaches, which neglect the three-dimensional
                      (3D) root architecture. Yet, nowadays 3D soil-root water and
                      solute models on plant-scale exist, which can be used for
                      assessing the impact of root architecture and root and soil
                      hydraulic resistances on the root uptake pattern and solute
                      transport and water flow in soil.In this thesis, we used a
                      numerical model, which offers the possibility to describe
                      soil and root interaction processes in a mechanistic manner
                      avoiding empirical descriptions of root water uptake as a
                      function of averaged water potential and root length
                      density. Water flow is simulated along water potential
                      gradients in the soil-root continuum and the model accounts
                      for solute movement and root solute uptake. Solute movement
                      in soils is modeled with a particle tracking algorithm. With
                      this model, three research questions are investigated. The
                      first study investigates how root water uptake affects the
                      velocity field, and thus the dispersivity length. The solute
                      breakthrough curves from the three-dimensional results and
                      different simulation setups were fitted with an equivalent
                      one-dimensional flow and transport model. The obtained
                      results of the apparent soil dispersivities show the effect
                      of the plant roots on solute movement, and illustrate the
                      relevance of small scale 3D water and solute fluxes, induced
                      by root water and nutrient uptake.Second, we show how local
                      matric and osmotic potentials affect root water uptake. We
                      analyze the difference between upscaled time and root-zone
                      integrated water potentials, as often measured in
                      experimental studies, and local water potentials at the
                      root-soil interface. In addition, we demonstrate the
                      relation between the shape of local stress function and the
                      global (time-integrated) plant stress response to salinity.
                      The last part explores how water uptake could be deduced
                      from tracer concentration distribution monitored in a
                      soil-plant system by Magnetic Resonance Imaging (MRI). We
                      show the effects of root system architecture, fine roots,
                      and root conductance on solute and compare numerical and
                      measured data. This shows the capabilities and limitations
                      of both, the model prediction and the MRI measurement
                      methodology. Furthermore, it points out the extensive effect
                      of root architecture and its conductance parameters on
                      solute spreading.},
      keywords     = {Dissertation (GND)},
      cin          = {JSC / IBG-3},
      cid          = {I:(DE-Juel1)JSC-20090406 / I:(DE-Juel1)IBG-3-20101118},
      pnm          = {411 - Computational Science and Mathematical Methods
                      (POF2-411) / 246 - Modelling and Monitoring Terrestrial
                      Systems: Methods and Technologies (POF2-246)},
      pid          = {G:(DE-HGF)POF2-411 / G:(DE-HGF)POF2-246},
      typ          = {PUB:(DE-HGF)11},
      urn          = {urn:nbn:de:0001-2013112209},
      url          = {https://juser.fz-juelich.de/record/151172},
}