EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Impact of drought on C forms and fluxes in the soil – plant continuum

Cornelia Rumpel1,2, Muhammad Sanaullah3, Maria de la Luz Mora2, Marcela Calabi Floody2, and Abad Chabbi4,5
Cornelia Rumpel et al.
  • 1CNRS, Institute of Ecology and Environment Paris, Thiverval-Grignon, France (
  • 2BIOREN, Universidad de la Frontera, Temuco, Chile
  • 3University of Agriculture, Faisalabad, Pakistan
  • 4INRA, Ecosys, Thiverval-Grignon, France
  • 5INRA, URP3F, Lusignan, France

Global change is likely to increase the drought periods, which may have significant consequences for the turnover of SOM, in particular through their effect on plants. The aim of the study was to assess different compartments of the soil – plant continuum for their response to drought stress by combining field and laboratory experiments. We focused on three common grassland species (Lolium perenne, Festuca arundinacea and Dactylis glomerata) found to constitute grasslands of the temperate climate. We investigated drought impact on (1) plant biochemistry and potential mineralization of this material in soil, (2) decomposition of aboveground plant leaf litter of different quality, (3) plant-mediated soil C fluxes including (4) soil microbial biomass and their enzyme activities in the rhizosphere.

            Plant elemental and biochemical composition showed contrasting changes depending on the species in response to drought stress. The changes in elemental and biochemical composition of leaf litter, ultimately influenced its mineralization in soil. Drought stress highly modified the decomposition dynamics of litter from the three grassland species as a function of litter quality.

                 Moreover, drought stress resulted in significant decrease in both shoot and root biomass in monocultures, while root biomass did not change when they were grown in mixture. Under drought stress, we observed higher belowground allocation of photosynthates and the drought had reduced root-derived respiration. This resulted in significant changes of soil enzyme activities.

                Our results suggest that plant species and community composition strongly influenced drought effects in the rhizosphere. Thus, management interventions should aim at influencing rhizosphere processes through their impact on microbial activities affecting C, N and water cycles. Plant community composition and in particular the introduction of legumes might be a tool to attenuate drought stress not only because of different water use efficiency by plants, but also by their indirect effects on these processes.

How to cite: Rumpel, C., Sanaullah, M., Mora, M. D. L. L., Calabi Floody, M., and Chabbi, A.: Impact of drought on C forms and fluxes in the soil – plant continuum, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12053,, 2020

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Presentation version 1 – uploaded on 04 May 2020
  • CC1: Comment on EGU2020-12053, Luiz Domeignoz-Horta, 04 May 2020

    Hi Cornelia,

    Very interesting work! I'm looking forward to this session to further discuss. My results show how drought disrupt the relationship between microbial diversity and carbon use efficiency in a model soil. If you want to see my results my title is "Microbial diversity drives carbon use efficiency in a model soil" and the link to my presentation:


    • AC1: Reply to CC1, Cornelia Rumpel, 04 May 2020

      could you please paste once more the link to your work?

      Thank you in advance


      • CC2: Reply to AC1, Luiz Domeignoz-Horta, 04 May 2020 

        Sorry the first time that I pasted it didn't work!

  • CC3: Comment on EGU2020-12053, Luiz Gustavo de Oliveira Denardin, 07 May 2020

    Dr. Cornelia, my congratulations on your presentation. It brings very interesting and robust data. I wonder about conducting long-term experiments that evaluate the forms and stock of Carbon in systems with irrigated cash or cover crops, in tropical/subtropical climate environments. What is your opinion about this? Especially considering the high risk of drought in these environments, in a reality that less than 10% of farmers can adopt an irrigation system. 

    • AC2: Reply to CC3, Cornelia Rumpel, 07 May 2020

      Dear Luiz,

      yes, you are right, tropical and subtropical systems are largely understudied. Long-term experiments are always needed, because effects especially on soil organic matter are slow. With regards to a particular cropping system, I would say that this really depends on local conditions. Of course, cover crops or crop associations that cover the soil constantly are always preferred. Also, it may be good to use native, adapted species instead of bringing in more fragile high yield crops. This decision however depends on the local conditions and the trade off between yield stability and quantity of grains to be harvested. Hope I answered to your questions.