Funding for this research was provided by:
Universität für Bodenkultur Wien (not applicable)
Received: 30 January 2019
Accepted: 8 July 2019
First Online: 12 July 2019
Ethics approval and consent to participate
: There did not arise any ethical issues, as the paper used data from the literature, where the fulfillment of the relevant ethical guidelines has been confirmed prior to the publication; for details c.f. the ARRIVE Guidelines Checklist that is provided as a supporting information.
: Not applicable.
: The authors declare that they have no conceivable competing interests.