Plant–microbe networks in soil are weakened by century‐long use of inorganic fertilizers

Summary

This field-based study examined how a century of continuous inorganic fertilisation has altered plant–microbe interactions in grassland at the Park Grass Experiment, Rothamsted Research. Both plant and soil microbial communities showed consistent reductions in richness and diversity under long-term fertilisation, accompanied by significant weakening of the ecological networks connecting plants to microbial functional communities. The findings suggest that prolonged synthetic nitrogen addition compromises soil ecosystem complexity and stability through reduced network connectivity and microbial association strength.

UK applicability

These findings are directly applicable to UK grassland management, as the Park Grass Experiment is a long-term observational study at a leading UK institution. The results provide evidence-based insights relevant to UK agricultural policy on fertiliser use and soil health, particularly for grasslands under intensive nutrient management.

Key measures

Plant species richness and diversity; soil microbial richness and diversity (detected by GeoChip); microbial functional gene abundance (C, N, P cycling genes); network node numbers, connectivity, network density, clustering coefficient; microbial association strength; soil carbon and nitrogen contents

Outcomes reported

The study measured changes in plant and soil microbial community composition, richness, diversity, and network characteristics in response to >150 years of fertilisation treatments. Network-based analyses quantified shifts in connectivity, density, clustering coefficients, and microbial functional gene abundance related to carbon, nitrogen and phosphorus cycling.

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