Positive effects of organic farming on below-ground mutualists: large-scale comparison of mycorrhizal fungal communities in agricultural soils

Authors

  • Erik Verbruggen,

    1. Department of Ecological Science, Faculty of Earth and Life Sciences, VU University Amsterdam, the Netherlands
    Search for more papers by this author
  • Wilfred F. M. Röling,

    1. Molecular Cell Physiology, Faculty of Earth and Life Sciences, VU University Amsterdam, the Netherlands
    Search for more papers by this author
  • Hannes A. Gamper,

    1. Netherlands Institute of Ecology (NIOO-KNAW), Department of Microbial Ecology, Boterhoeksestraat 48, 6666 GA Heteren, Heteren, the Netherlands
    2. Botanical Institute, University of Basel, Hebelstrasse 1, CH-4056 Basel, Switzerland
    Search for more papers by this author
  • George A. Kowalchuk,

    1. Department of Ecological Science, Faculty of Earth and Life Sciences, VU University Amsterdam, the Netherlands
    2. Netherlands Institute of Ecology (NIOO-KNAW), Department of Microbial Ecology, Boterhoeksestraat 48, 6666 GA Heteren, Heteren, the Netherlands
    Search for more papers by this author
  • Herman A. Verhoef,

    1. Department of Ecological Science, Faculty of Earth and Life Sciences, VU University Amsterdam, the Netherlands
    Search for more papers by this author
  • Marcel G. A. van der Heijden

    1. Department of Ecological Science, Faculty of Earth and Life Sciences, VU University Amsterdam, the Netherlands
    2. Ecological Farming Systems, Research Station ART, Agroscope Reckenholz Tänikon, Zürich, Switzerland
    3. Plant–Microbe Interactions, Institute of Environmental Biology, Faculty of Science, Utrecht University, 3508 TB, Utrecht, the Netherlands
    Search for more papers by this author

Author for correspondence:
Marcel G. A. van der Heijden
Tel: ++41 44 377 7278
Email: marcel.vanderheijden@art.admin.ch

Summary

  • The impact of various agricultural practices on soil biodiversity and, in particular, on arbuscular mycorrhizal fungi (AMF), is still poorly understood, although AMF can provide benefit to plants and ecosystems. Here, we tested whether organic farming enhances AMF diversity and whether AMF communities from organically managed fields are more similar to those of species-rich grasslands or conventionally managed fields.
  • To address this issue, the AMF community composition was assessed in 26 arable fields (13 pairs of organically and conventionally managed fields) and five semi-natural grasslands, all on sandy soil. Terminal restriction fragment length polymorphism community fingerprinting was used to characterize AMF community composition.
  • The average number of AMF taxa was highest in grasslands (8.8), intermediate in organically managed fields (6.4) and significantly lower in conventionally managed fields (3.9). Moreover, AMF richness increased significantly with the time since conversion to organic agriculture. AMF communities of organically managed fields were also more similar to those of natural grasslands when compared with those under conventional management, and were less uniform than their conventional counterparts, as expressed by higher β-diversity (between-site diversity).
  • We suggest that organic management in agro-ecosystems contributes to the restoration and maintenance of these important below-ground mutualists.

Ancillary