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@ARTICLE{Stumpe:17682,
      author       = {Stumpe, B. and Weihermüller, L. and Marschner, B.},
      title        = {{S}ample preparation and selection for qualitative and
                      quantitative analyses with mid-infrared reflectance
                      spectroscopy},
      journal      = {European journal of soil science},
      volume       = {62},
      issn         = {1351-0754},
      address      = {Oxford [u.a.]},
      publisher    = {Wiley-Blackwell},
      reportid     = {PreJuSER-17682},
      pages        = {849 - 862},
      year         = {2011},
      note         = {Record converted from VDB: 12.11.2012},
      abstract     = {Mid-infrared spectroscopy (MIRS) is a well-established
                      analytical tool for qualitative and quantitative analysis of
                      soil samples. However, effects of soil sample grinding
                      procedures on the prediction accuracy of MIR models and on
                      qualitative spectral information have not been well
                      investigated and, in consequence, not standardized up to
                      now. Further, the effects of soil sample selection on the
                      accuracy of MIR prediction models has not been quantified
                      yet. This study investigated these effects by using 180
                      well-characterized soil samples that were ground for
                      different times (0, 2 or 4 minutes) and then used for MIR
                      measurements. To study the impact of sample preparation,
                      soil spectra were subjected to principal component analyses
                      (PCA), multiple regression and partial least square (PLS)
                      analysis. The results indicate that the prediction accuracy
                      of MIR models for soil organic carbon (SOC) and pH and the
                      qualitative spectral information were better overall for
                      lightly ground (2 minutes) soil samples compared with
                      intensively (4 minutes) or unground soil samples. Whereas
                      the grinding procedure did not show any effect on spectra of
                      clay minerals, spectral information for quartz and for SOC
                      was modified. Even though it is difficult to recommend a
                      global standardized soil sample grinding procedure for MIR
                      measurements because of different mill types available
                      within laboratories, we highly recommend using an internally
                      standardized grinding procedure. Moreover, we show that
                      neither land use nor soil sampling depth influences the
                      prediction of the SOC content. However, sand and clay
                      content substantially affect the score vectors used by the
                      PLS algorithm to predict the SOC content. Thus, we recommend
                      using soil samples similar in texture for more precise SOC
                      calibration models for MIR spectroscopy.},
      cin          = {IBG-3},
      ddc          = {630},
      cid          = {I:(DE-Juel1)IBG-3-20101118},
      pnm          = {Terrestrische Umwelt},
      pid          = {G:(DE-Juel1)FUEK407},
      shelfmark    = {Soil Science},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000297206100007},
      doi          = {10.1111/j.1365-2389.2011.01401.x},
      url          = {https://juser.fz-juelich.de/record/17682},
}