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Plant species, nitrogen status and endophytes are drivers of soil microbial communities in grasslands

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posted on 2023-09-28, 22:24 authored by Susanne Rasmussen, Anthony J. Parsons, Julia Russell, Daniel A. Bastías CamposDaniel A. Bastías Campos, Qianhe LiuQianhe Liu

Context: There is concern that the introduction of ‘novel’ plant germplasm/traits could outpace our capacity to measure and so assess their impacts on soil microbial communities and function.

Aim: This study aimed to investigate the effects of plant species/functional traits, nitrogen (N) fertilisation and endophyte infection on grassland soil microbial communities within a short time span of 2 years.

Methods: Two field experiments with monoculture plots were conducted in a common soil. Experiment 1 compared grasses and legumes, using two cultivars of perennial ryegrass (Lolium perenne) that varied in fructan content, along with the legumes white clover (Trifolium repens) and bird’s-foot trefoil (Lotus pedunculatus) that varied in tannin content. Grass treatments received high and low N application levels. Experiment 2 compared the presence/absence of Epichloë strains in ryegrass, tall fescue (Schedonorus phoenix) and meadow fescue (Schedonorus pratensis). Soil microbial communities were analysed by using high-throughput sequencing of DNA isolated from bulk soil cores.

Key results: Higher abundance of ligninolytic fungi was found in grass soils and pectinolytic fungi in legume soils. Levels of N fertilisation and fructan in ryegrass had only minor effects on soil fungal communities. By contrast, N fertilisation or fixation had a strong effect on bacterial communities, with higher abundance of nitrifiers and denitrifiers in high-N grass soils and in legume soils than in low-N grass soils. Epichloë affected soil microbiota by reducing the abundance of certain fungal phytopathogens, increasing mycorrhizal fungi and reducing N-fixing bacteria.

Conclusions: Chemical composition of plant cell walls, which differs between grasses and legumes, and presence of Epichloë in grasses were the main drivers of shifts in soil microbial communities.

Implications: Impacts of farming practices such as mono- or poly-culture, N fertilisation and presence of Epichloë in grasses on soil microbial communities should be considered in pasture management.

Funding

New Zealand Ministry of Business, Innovation and Employment (Contract ID C10X0903)

History

Rights statement

© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)

Publication date

2023-09-27

Project number

  • Non revenue

Language

  • English

Does this contain Māori information or data?

  • No

Publisher

CSIRO

Journal title

Crop & Pasture Science

ISSN

1836-0947

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