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@ARTICLE{Stadler:187365,
      author       = {Stadler, Anja and Rudolph, Sebastian and Kupisch, Moritz
                      and Langensiepen, Matthias and van der Kruk, Jan and Ewert,
                      Frank},
      title        = {{Q}uantifying the effects of soil variability on crop
                      growth using apparent soil electrical conductivity
                      measurements},
      journal      = {European journal of agronomy},
      volume       = {64},
      issn         = {1161-0301},
      address      = {Amsterdam [u.a.]},
      publisher    = {Elsevier Science},
      reportid     = {FZJ-2015-01036},
      pages        = {8 - 20},
      year         = {2015},
      abstract     = {Spatial heterogeneity of crop growth within fields is
                      rarely quantified but essential for estimating yield and
                      optimizing crop management. Relationships in fields between
                      crop growth and soil physical characteristics have been
                      described before but an unrealistically high number of
                      invasive measurements have to be made to obtain spatially
                      continuous soil information. Alternatively, non-invasive
                      methods are available for characterizing soil heterogeneity
                      but relationships to growth characteristics have rarely been
                      investigated. Here, we use an electromagnetic induction
                      (EMI) sensor to measure the apparent electromagnetic
                      conductivity of the soil (ECa), which can be used as a proxy
                      for the relative spatial variability of the prevailing soil
                      properties. We evaluate relationships between ECa and soil
                      and crop characteristics assuming that measured ECa patterns
                      relate to observed growth patterns in the field. The test
                      fields were located in Western Germany where different crops
                      (winter wheat, winter barley, and sugar beet) were grown
                      between 2011 and 2013. Measurements include soil texture,
                      soil moisture and crop growth characteristics taken
                      frequently throughout the vegetation periods for plant
                      height, leaf area index (LAI), dry matter of plants and
                      selected organs (green leaves and storage organs). Spatial
                      variability was observed for soil and crop characteristics
                      that differed among fields, crops and years. Good
                      correlations between ECa and soil texture and soil moisture
                      confirmed that ECa measurements are suitable for
                      characterizing spatial differences in soil properties for
                      our test sites. Averaged over all sampling dates of a
                      vegetation period the differences in the spatial variability
                      of crop characteristics were small between the years and
                      crops considered. However, the within-field crop growth
                      heterogeneity changed throughout the growing period
                      depending on the crop development stage. Correlations were
                      found between ECa and the crop characteristics that varied
                      with time and were most pronounced in the main growth phase
                      when LAI approached its maximum. Crop height correlated
                      better with ECa than yield, LAI, and dry matter but
                      differences were observed between fields, years and crops.
                      Our results suggest that in dry years soil patterns have a
                      stronger influence on the crop growth patterns than in
                      wetter years when water limitation is less severe. We
                      conclude that ECa measurements are suitable for detecting
                      spatial patterns in soil characteristics that influence the
                      spatial crop growth patterns for the region, years and crops
                      considered. However, relationships between patterns in crop
                      growth and soil characteristics within fields are more
                      complex and require further investigation.},
      cin          = {IBG-3},
      ddc          = {630},
      cid          = {I:(DE-Juel1)IBG-3-20101118},
      pnm          = {255 - Terrestrial Systems: From Observation to Prediction
                      (POF3-255) / 255 - Terrestrial Systems: From Observation to
                      Prediction (POF3-255)},
      pid          = {G:(DE-HGF)POF3-255 / G:(DE-HGF)POF3-255},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000349425100002},
      doi          = {10.1016/j.eja.2014.12.004},
      url          = {https://juser.fz-juelich.de/record/187365},
}