AUTHOR=Unger Stephan , Habermann Franziska M. , Schenke Katarina , Jongen Marjan 

TITLE=Arbuscular Mycorrhizal Fungi and Nutrition Determine the Outcome of Competition Between Lolium multiflorum and Trifolium subterraneum

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.778861

DOI=10.3389/fpls.2021.778861

ISSN=1664-462X

ABSTRACT=<p>Arbuscular mycorrhizal fungi (AMF) may affect competitive plant interactions, which are considered a prevalent force in shaping plant communities. Aiming at understanding the role of AMF in the competition between two pasture species and its dependence on soil nutritional status, a pot experiment with mycorrhizal and non-mycorrhizal <italic>Lolium multiflorum</italic> and <italic>Trifolium subterraneum</italic> was conducted, with manipulation of species composition (five levels), and nitrogen (N)- and phosphorus (P)- fertilization (three levels). In the non-mycorrhizal state, interspecific competition did not play a major role. However, in the presence of AMF, <italic>Lolium</italic> was the strongest competitor, with this species being facilitated by <italic>Trifolium</italic>. While N-fertilization did not change the competitive balance, P-fertilization gave <italic>Lolium</italic>, a competitive advantage over <italic>Trifolium</italic>. The effect of AMF on the competitive outcome may be driven by differential C-P trade benefits, with <italic>Lolium</italic> modulating carbon investment in the mycorrhizal network and the arbuscule/vesicle ratio at the cost of <italic>Trifolium</italic>.</p>