Agricultural intensification reduces microbial network complexity and the abundance of keystone taxa in roots

Summary

This study compared root-associated fungal communities across three farming systems in Switzerland, finding that organic farming harboured significantly more complex fungal networks with higher connectivity and greater abundance of keystone mycorrhizal taxa than conventional and no-till systems. Agricultural intensification showed a strong negative association with fungal network connectivity (R² = 0.366). The majority of keystone taxa identified form arbuscular mycorrhizal associations and belong to Glomerales, Paraglomerales, and Diversisporales, with their occurrence best predicted by soil phosphorus levels, bulk density, pH, and mycorrhizal colonisation.

Regional applicability

The study was conducted in Switzerland using wheat, a major UK cereal crop, making the findings potentially applicable to United Kingdom arable farming systems. However, transferability depends on soil type, climate, and crop varieties; UK farmers should consider whether local conditions and farming practices align with the Swiss no-till and conventional systems studied. The broad principles regarding organic farming and soil fungal complexity are likely transferable, but field validation in UK contexts would strengthen evidence for domestic policy and practice.

Key measures

Root fungal network connectivity; abundance and occurrence of keystone taxa; mycorrhizal colonisation rates in roots and soils; soil phosphorus, bulk density, and pH; coefficient of determination (R² = 0.366) between agricultural intensification and network connectivity

Outcomes reported

The study measured root fungal community composition, network connectivity, and the abundance of keystone taxa across conventional, no-till, and organic wheat farming systems using PacBio SMRT sequencing on samples from 60 Swiss farmlands. It quantified the association between agricultural intensification intensity and fungal network complexity, and identified soil factors (phosphorus, bulk density, pH, mycorrhizal colonisation) explaining keystone taxa occurrence.

Topic tags