Cover crop species influences soil fungal species richness and community structure

Authors: Muturi, Ephantus; Dunlap, Christopher; PERRY, WILLIAM - Illinois State University; RHYKERD, ROBERT - Illinois State University

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/24/2024
Publication Date: 9/12/2024
Citation: Muturi, E.J., Dunlap, C.A., Perry, W.L., Rhykerd, R.L. 2024. Cover crop species influences soil fungal species richness and community structure. PLOS ONE. 19(9). Article e0308668. https://doi.org/10.1371/journal.pone.0308668.
DOI: https://doi.org/10.1371/journal.pone.0308668

Interpretive Summary: Cover crops can enhance soil health in agricultural systems and reduce environmental impacts of conventional agricultural practices. Soil microbes are key contributors of soil health and cover crops are known to influence their composition and structure. However, the influence of specific cover crop species on soil microbes remains poorly understood. To address this, we evaluated the influence of three cover crop treatments, cereal ryegrass, wild pennycress, and a mixture of pea, clover, radish, and oat on soil fungal communities relative to no cover crop treatment. All three cover crop treatments enhanced soil fungal species richness but only cereal ryegrass enhanced soil fungal diversity and changed the fungal community structure. Cover cropping with cereal ryegrass and wild pennycress reduced the abundance of genus Fusarium which includes some of the most economically destructive pathogens. Additionally, all three cover crops enhanced the abundance of genus Mortierella, which is known to promote plant health. These findings demonstrate that cover cropping can increase soil fungal species richness and potentially reduce the abundance of some plant pathogens. However, these effects are dependent on cover crop species, a factor that should be considered when selecting appropriate cover crops for a particular cropping system.

Technical Abstract: Despite the well documented link between cover cropping and soil microbiology, the influence of specific cover crop species on soil microbes remains poorly understood. We evaluated how soil fungal communities in a no till system respond to four cover crop treatments: no cover crop (REF), cereal ryegrass (CRYE), wild pennycress (WPEN), and a mix of pea, clover, radish, and oat (PCRO). Soil samples were collected from experimental plots following termination of cover crops from depths of 0-2 cm and 2-4 cm where cover crops had significantly increased soil organic matter. There was no significant interaction between soil depth and cover crop treatment on either alpha diversity or beta diversity. All cover crop treatments (CRYE, PCRO, and WPEN) enhanced soil fungal richness but only CRYE enhanced soil fungal diversity and altered the fungal community structure. Soil depth altered the fungal community structure but had no effect on fungal diversity and richness. Genus Fusarium which includes some of the most economically destructive pathogens was more abundant in REF and PCRO treatments compared to CRYE and WPEN. In contrast, genus Mortierella which is known to promote plant health was more abundant in all cover crop treatments relative to the REF. These findings demonstrate that cover cropping can increase soil fungal species richness and alter fungal community structure, potentially promoting the abundance of beneficial fungi and reducing the abundance of some plant pathogens within the genus Fusarium. These effects are dependent on cover crop species, a factor that should be considered when selecting appropriate cover crops for a particular cropping system.