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@INPROCEEDINGS{Uhlig:1007639,
      author       = {Uhlig, David and Berns, Anne E. and Wu, Bei and Amelung,
                      Wulf},
      title        = {{M}ean nutrient uptake depths of cereal crops change with
                      compost incorporation into subsoil – evidence from
                      87{S}r/86{S}r ratios and potential for {M}g stable isotopes},
      reportid     = {FZJ-2023-02131},
      year         = {2023},
      abstract     = {Root restricting layers often hinder crops from accessing
                      the large reservoir of bioavailable mineral nutrients
                      situated in the subsoil. This study aimed i) at exploring
                      changes in the mean nutrient uptake depth of cereal crops by
                      means of 87Sr/86Sr ratios when removing root restricting
                      layers through subsoil management, and ii) at testing Mg
                      stable isotopes as a new analytical proxy in plant/soil
                      sciences to simultaneously identify changes in the mean
                      nutrient uptake depth and to quantify the Mg use efficiency
                      of crops defined here, as the ratio of Mg uptake versus Mg
                      supply.Subsoil management was performed by deep loosening,
                      cultivation of lucerne as deep-rooting pre-crop, and their
                      combination with compost incorporation. Management effects
                      were evaluated by means of shoot biomass and element
                      concentrations in shoots and soil compartments. The mean
                      nutrient uptake depth was fingerprinted by matching the
                      87Sr/86Sr ratios in shoots with the 87Sr/86Sr ratios in the
                      exchangeable fraction in soil. The feasibility of Mg stable
                      isotopes was demonstrated conceptually by simulating subsoil
                      management on soils with low, middle, and high inventories
                      of bioavailable Mg and crops typically cultivated in
                      Germany, which was further validated in the field trials of
                      this study.Shoot biomass remained constant in management and
                      control plots. The mean nutrient uptake depth, inferred from
                      87Sr/86Sr ratios, changed with subsoil management in the
                      order: deep loosening < control < deep loosening with
                      compost incorporation. The latter coincided with a
                      reallocation of compost-derived sodium and hence resulted in
                      increased levels of bioavailable Na below the depth of
                      compost incorporation. This increased level of bioavailable
                      sodium at depth may have led to an improved water use
                      efficiency of the crops, and thus triggered the deepening of
                      the mean uptake depth of water and nutrients. Moreover,
                      nutrient uplift from depth into topsoil was evident 21
                      months after subsoiling as suggested by both 87Sr/86Sr
                      ratios and the Mg isotope composition of soil
                      compartments.Subsoil management by deep loosening with
                      compost incorporation provides a sustainable use of soil
                      resources because otherwise unused deep geogenic-derived
                      nutrient reservoirs can be additionally involved in crop
                      nutrition. The application of Mg stable isotopes as a new
                      geochemical routine for agronomy is promising but requires
                      future work focussing on isotope fractionation factors
                      related to crop uptake and intra-plant translocation of Mg,
                      which may depend on species, environmental conditions, and
                      nutrient status, to allow minimally invasive sampling of the
                      soil-plant system and to reduce sample sets.},
      month         = {May},
      date          = {2023-05-15},
      organization  = {Bonares Conference 2023, Berlin
                       (Germany), 15 May 2023 - 17 May 2023},
      subtyp        = {Other},
      cin          = {IBG-3},
      cid          = {I:(DE-Juel1)IBG-3-20101118},
      pnm          = {2173 - Agro-biogeosystems: controls, feedbacks and impact
                      (POF4-217) / BonaRes - (Modul A, Phase 2): Soil3-II -
                      Nachhaltiges Unterbodenmanagement, Teilprojekt C
                      (031B0515C)},
      pid          = {G:(DE-HGF)POF4-2173 / G:(BMBF)031B0515C},
      typ          = {PUB:(DE-HGF)6},
      url          = {https://juser.fz-juelich.de/record/1007639},
}