1. Unpublished observations in climate chambers and in the field by Markus Hoffmann
  2. Unpublished observations in climate chambers
  3. Field observations
  4. Mean values from own growth experiments (M. Hoffmann et al., 2013; M. A. Hoffmann et al., 2014)
  5. Values adjusted to the observed values within the described datasets. Derived by means of Hill function of the real distribution (quantitative) of the reference species as a function of the total phosphate values. Assumption: direct correlation between photosynthesis rate and plant quantity.
  6. (van Nes et al., 2003)
  7. (Kleyer et al., 2008)
  8. Expert knowledge
  9. Arbitrary