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@PHDTHESIS{Wegner:44696,
      author       = {Wegner, Reinhard},
      title        = {{S}tudies on the {E}ffect of {S}oil {M}oisture and {T}ime
                      of {A}pplication on the {D}istribution of the {H}erbicide
                      {P}ropoxycarbazone-{S}odium ({BAY} {MKH}6561) in {P}lants
                      ({W}heat, {B}lackgrass) and {S}oil},
      volume       = {4163},
      issn         = {0944-2952},
      school       = {Univ. Bonn},
      type         = {Dr. (Univ.)},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {PreJuSER-44696, Juel-4163},
      series       = {Berichte des Forschungszentrums Jülich},
      year         = {2005},
      note         = {Record converted from VDB: 12.11.2012; Bonn, Univ., Diss.,
                      2004},
      abstract     = {The distribution and concentration of
                      propoxycarbazone-sodium (MKH6561) (a.i.) and its metabolites
                      in plant and soil were investigated. Soil columns and
                      lysimeters were used to examine the dependence of the
                      herbicide action on soil moisture and time of application
                      for crop (wheat) and target grass (ALOMY). Before
                      application of [phenyl-UL-$^{14}$C] labelled MKH6561,
                      various levels of soil moisture (20 to 60\%WHC$_{max}$) were
                      adjusted in orthic luvisol and gleyic cambisol. After the
                      application at growth stages BBCH22 and 25, different
                      precipitation events were simulated ("normal" precipitation
                      vs. heavy rain). The aim was thus to provide information on
                      plant uptake, translocation in soil and metabolization of
                      a.i. as a function of soil moisture and growth stage. The
                      results will be used to optimise the effectiveness of the
                      compound. The experiments show higher total MKH6561 content
                      in ALOMY due to the position of the main root horizon
                      ("position selectivity"), compared to the deeper-rooting
                      wheat. Wheat displayed lower percentage content of a.i. but
                      higher content of the major plant metabolite
                      (2-hydroxypropoxy-MKH6561) and thus better tolerance due to
                      faster metabolization. ALOMY showed a similar distribution
                      of both fractions and slowed down "detoxification". On the
                      whole, the concentration [μg/g] of all the fractions
                      considered was higher in ALOMY due to higher total MKH6561
                      content than in wheat. Due to the increase in mass of the
                      plants and the resulting dilution effect, higher total
                      MKH6561 content was found at the early (BBCH22), and lower
                      content at the later application date (BBCH25), where a
                      reduced effect of the herbicide is to be assumed. The soil
                      moisture is the most important factor responsible for
                      herbicide uptake. Thus, at high soil moisture, the greatest
                      herbicidal effect and, at the same time, the greatest danger
                      to the crop is to be expected. Due to lower pressure head at
                      identical soil moisture on gleyic cambisol in comparison to
                      orthic luvisol, high uptake rates and effectiveness of the
                      herbicide in ALOMY on gleyic cambisol can be estimated. In
                      the soil, at high moisture, elevated translocation is to be
                      expected. In the subsoil, the concentrations further
                      increase with advancing time after application. Heavy rain
                      led to elevated translocation and plant uptake due to
                      downward water flow and the increase of soil moisture,
                      respectively. In gleyic cambisol, in comparison to orthic
                      luvisol, a higher hydraulic conductivity, lower effective
                      retardation and lower sorptive properties (weak sorption of
                      a.i. to the soil matrix, low KOC values) were identified due
                      to a high sand and coarse pore fraction. Thus, stronger
                      translocation is to be expected in gleyic cambisol but
                      concentrations of >1 $\mu$g/kg or contents of >1\% of the
                      applied quantity in subsoil layers can be ruled out.
                      Metabolization takes place more slowly than in the plant,
                      forming one major soil metabolite (4-hydroxysaccharin) which
                      accumulates in soil. Degradation in gleyic cambisol was
                      faster than in orthic luvisol.},
      cin          = {ICG-IV},
      cid          = {I:(DE-Juel1)VDB50},
      pnm          = {Chemie und Dynamik der Geo-Biosphäre},
      pid          = {G:(DE-Juel1)FUEK257},
      typ          = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
      url          = {https://juser.fz-juelich.de/record/44696},
}