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@PHDTHESIS{RoblesAguilar:842872,
      author       = {Robles Aguilar, Ana Alejandra},
      othercontributors = {Rascher, Uwe},
      title        = {{T}owards a more efficient and sustainable fertilization
                      through recycling phosphorus as struvite},
      school       = {Bonn},
      type         = {Dissertation},
      reportid     = {FZJ-2018-01045},
      pages        = {159},
      year         = {2018},
      note         = {Dissertation, Bonn, 2017},
      abstract     = {Food and water security are dependent on the sustainable
                      use of phosphorus (P). However, there is no single solution
                      for achieving a phosphorus-secure future. P recovered and
                      recycled from current waste streams (like manure) is an
                      important approach to developing environmentally sustainable
                      and biologically efficient fertilizers. In this framework, a
                      promising example of a P recovery product from waste streams
                      is struvite (MgNH4PO4 6H2O), a crystal precipitated after
                      the anaerobic digestion of different biological waste
                      streams. Struvite has reported positive results regarding
                      yields and P uptake for different crop species; however,
                      there are still some limitations. P availability from
                      struvite is highly influenced by the soil pH, which can be
                      further modified by nutrients added to the soil or by plant
                      and microbial activy in the rhizosphere. The main challenges
                      are i) to understand the essential aspects that have a major
                      effect on struvite availability, and ii) to focus on those
                      traits that will increase struvite availability and
                      therefore improve fertilizer use efficiency. With this
                      apporoach, struvite value will increase, making it more
                      competitive against mineral fertilizers.To understand which
                      aspects modify struvite availability, the response of
                      different plant species with contrasting strategies to
                      mobilize nutrients (i.e. maize, lupine, and tomato) to
                      various P applications was analyzed at different time points
                      and plant growth stages. Likewise, the effect of soil pH,
                      and method and duration of application were studied. Plant
                      species have different morphological and physiological
                      adaptations to increase the efficiency of P acquisition.
                      Under this premise, a particular focus was put on root
                      traits that would have an effect on phosphorus
                      bioavailability and spatial availability.It was concluded
                      that struvite has the same P fertilizer efficiency as
                      mineral sources regarding biomass production, P uptake
                      efficiency, and allometric studies of root–shoot
                      relations. Moreover, it was validated that the following
                      traits contributed to increase struvite use efficiency: i)
                      the results from the automatic shoot phenotyping analyses
                      support the idea of struvite being a slow-release; compared
                      to triple-superphosphate (TSP), struvite-fertilized plants
                      had lower initial leaf area, but later higher biomass ii)
                      plant responses were conditoned by the nutrients applied
                      with the struvite. It was confirmed that nitrate increased
                      root biomass due to a higher number of primary roots, while
                      ammonium increased the phosphorus uptake efficiency from
                      struvite due to rhizosphere acidification iii) it was
                      observed that lupine plants acidified the soil due to a high
                      release of carboxylates by the roots. In contrast to the
                      readily available P source K2PO4, the carobxylate exudation
                      increased when struvite was applied, mobilizing the
                      struvite-P at neutral conditions; iv) the microbial
                      community analyzed did not shift between fertilizers used,
                      as much as between plant species.Throughout this thesis, the
                      use of invasive and non-invasive techniques, revealed
                      different plant responses at various growth stages above and
                      below ground, depending on the P fertilizer applied. It was
                      shown that struvite solubility will not only depend on the
                      soil pH but also will be modulated by the plant species and
                      the way in which it is applied (e.g combined with other
                      nutrients). In addition to yield analyses, studies of root
                      morphological and physiological adaptations to P application
                      provided a more detailed report of traits that would
                      increase struvite use efficiency. It was shown that
                      struvite, with a slower release, has the potential to be a
                      more efficient method of fertilizing plants than the
                      application of conventional, highly soluble P fertilizers.
                      Likewise, the use of plants that can actively acidify the
                      soil, combined with the application of the struvite with
                      ammonium-N, will increase the P use efficiency. For future
                      applications, those traits can be used to select candidate
                      plants that will increase the use effiiciency of struvite,
                      underlying mechanisms that will also ensure high yields.
                      Those studies have the potential to be applied for other
                      recovered products, increasing the efficiency and promoting
                      the recycling of nutrients.},
      cin          = {IBG-2},
      cid          = {I:(DE-Juel1)IBG-2-20101118},
      pnm          = {582 - Plant Science (POF3-582)},
      pid          = {G:(DE-HGF)POF3-582},
      typ          = {PUB:(DE-HGF)11},
      url          = {https://juser.fz-juelich.de/record/842872},
}