Fostering populations of arbuscular mycorrhizal (AM) fungi through cover crop choices and soil management (PhD)

Over 70% of land plants form a mutually beneficial (symbiotic) relationship with arbuscular mycorrhizal (AM) fungi, including many key agricultural crops.

This study examined the impact of several farming practices – cover cropping and amendments – on the diversity and abundance of AM fungi, and crop yields.

A large-scale analysis of AM fungal diversity in UK agriculture (in collaboration with FERA) provided a framework for further analysis of how cover crops and soil amendments influence AM fungal communities.

In total, 84 AM fungal Virtual Taxa were identified from across the 67 independent sites in the trial.

Replicated field trials provided evidence that multiple iterations of cover crops can increase the extent to which plants are colonised by AM fungi (single iterations had no measurable impact).

In the New Farming Systems (fertility building) trial, repeat applications of nitrogen fertiliser over several years influenced AM fungal community composition. However, this was not observed in a shorter field-scale validation experiment that used anaerobic digestate as the nitrogen source.

In this trial, there was no link between increased diversity and abundance of AM fungi, and increased crop growth or yield.

In another trial (Bawburgh, Norfolk), the addition of a commercial AM fungal inoculum had little impact on the AM fungal community, crop growth or yield in field conditions.

This further suggests that multiple iterations of soil amendments are required to cause measurable, long-term shifts in AM fungal diversity and other soil benefits.

Finally, field-scale experiments provided some evidence that cover crops or AM fungal inoculum could positively influence AM fungal abundance or diversity and crop yield.

Also..

• Video: Student George Crane provides and overview of the research
• Find out about an on-farm trial network (BOFIN) investigating AMF