EGU General Assembly 2020
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the Creative Commons Attribution 4.0 License.

Pore size effect on soil carbon dynamics during decomposition of switchgrass

Kyungmin Kim, Andrey Guber, and Alexandra Kravchenko
Kyungmin Kim et al.
  • Michigan State University, Plant, Soil, and Microbial Sciences, East Lansing, United States of America (

Soil pore size distribution (PSD) regulates oxygen diffusion and transport of water/mineralized nutrients. Microbial activity, which drives the carbon (C) cycle in the soil system, can react to these physical factors regulated by PSD. In this study, we investigated the contribution of PSD to C-related microbial activity during the switchgrass decomposition. We used two types of soils, which have controlled PSD (dominant pore size of < 10um and > 30 um). 13C labeled switchgrass leaf and root were incorporated into different PSD of soils and incubated for 21 days under 50% water-filled pore space. During the incubation, microbial activity was assessed with several indicators. i) Fate and transport of mineralized switchgrass, ii) Priming effect, iii) Spatial distribution of b-glucosidase and phenol oxidase, and iv) Microbial biomass. Our preliminary results showed that CO2 emission from switchgrass leaf was greater in the soil dominated by < 10 um pores. Higher b -glucosidase activity and mineralized C from switchgrass leaf supported greater C-related activity in such soil. However, interestingly, we observed a greater priming effect in the soil dominated by > 30 um pores. Due to the less mineralization and transport of switchgrass-derived C in such pores, enzymes targeting more complex substrate could be more active in such soil stimulating mineralization of native soil C. Our full results of phenol oxidase, microbial biomass, and more detailed analysis on 13C and C dynamics will help understanding how PSD can affect biochemical reactions in plant decomposition system.

How to cite: Kim, K., Guber, A., and Kravchenko, A.: Pore size effect on soil carbon dynamics during decomposition of switchgrass, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-1148,, 2019

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Presentation version 1 – uploaded on 05 May 2020
  • CC1: Comment on EGU2020-1148, Shun Hasegawa, 08 May 2020

    Great talk and excellent presentation. Very comprehensive research and really fascinating results. 

    • AC1: Reply to CC1, Kyungmin Kim, 08 May 2020

      Dear Dr. Hasegawa

      Thank you for encouraging me! That means a lot:)

      I hope this project will be available in a more well-organized version via publication.

      I wish that your research goes well too.

      Thank you:)

      Alyssa Kim 

  • CC2: Comment on EGU2020-1148, Adetunji Alex Adekanmbi, 08 May 2020

    Dear Kim,

    I found your work really interesting and especially the use of zymography in monitoring glucosidase activities from soils of different pore sizes.

    I am following this up with an email request.

    Well done!



    • AC2: Reply to CC2, Kyungmin Kim, 08 May 2020

      Thank you, Alex! I replied to your email and provided useful publications from Dr. Kuzyakov from Universitat of Gottingen, Germany. I hope that helps you to understand more about Zymography.

      • CC3: Reply to AC2, Adetunji Alex Adekanmbi, 08 May 2020

        Thank you Kim.

        It does, I am actually looking at one of the papers sent.

        I wish you a progressive search.