EGU2020-13534, updated on 10 Jan 2024
https://doi.org/10.5194/egusphere-egu2020-13534
EGU General Assembly 2020
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Variability of ecosystem scale water-use efficiency in a nutrient manipulation experiment

Tarek EI-Madany1, Markus Reichstein1, Arnaud Carrara2, M. Pilar Martin3, Gerardo Moreno4, Rosario Gonzalez-Cascon5, Josep Penuelas6,7, Vicente Burchard-Levin3, Tiana Hammer1, Jürgen Knauer1,8, Olaf Kolle1, Yunpeng Luo1, Javier Pacheco-Labrador1, Oscar Perez-Priego1,9, Victor Rolo4, Thomas Wutzler1, and Mirco Migliavacca1
Tarek EI-Madany et al.
  • 1Max Planck Institute for Biogeochemistry, Department Biogeochemical Integration Germany (telmad@bgc-jena.mpg.de)
  • 2Centro de Estudios Ambientales del Mediterráneo (CEAM)
  • 3Environmental Remote Sensing and Spectroscopy Laboratory (SpecLab)
  • 4Forest Research Group, INDEHESA, University of Extremadura
  • 5National Institute for Agriculture and Food Research and Technology, Department of Environment
  • 6CSIC, Global Ecology Unit CREAF-CEAB-UAB
  • 7CREAF, Campus de Bellaterra (UAB)
  • 8CSIRO Oceans and Atmosphere
  • 9Department of Biological Sciences, Macquarie University

Nitrogen (N) and phosphorus (P) are the two most important limiting soil nutrients reducing carbon sequestration globally. Through anthropogenic N-deposition, stoichiometric imbalances in plant-available N and P are expected in terrestrial ecosystems. This will result in increased P-limitation to plants and associated, but yet understudied, implications for ecosystem carbon sequestration, water-use efficiency (WUE), and biophysical properties. Here, we show results of a large-scale fertilization experiment designed to quantify effects of stoichiometric N:P ratio imbalances on WUE in a semi-arid tree-grass ecosystem. At the ecosystem-scale, the addition of N increased leaf area index, canopy chlorophyll content, and WUE. The addition of P, which relived the N:P imbalance, resulted in a further increase of WUE, more fixed carbon per transpired water. We conclude that increased N and combined N+P addition leads to shifts in many aspects of ecosystem functioning and biophysics, in particular related to water use strategies.

How to cite: EI-Madany, T., Reichstein, M., Carrara, A., Martin, M. P., Moreno, G., Gonzalez-Cascon, R., Penuelas, J., Burchard-Levin, V., Hammer, T., Knauer, J., Kolle, O., Luo, Y., Pacheco-Labrador, J., Perez-Priego, O., Rolo, V., Wutzler, T., and Migliavacca, M.: Variability of ecosystem scale water-use efficiency in a nutrient manipulation experiment , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13534, https://doi.org/10.5194/egusphere-egu2020-13534, 2020.

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