Fostering Populations of Arbuscular Mycorrhizal Fungi Through Cover Crop Choices and Soil Management

Abstract

Over 70% of land plants, including many key agricultural crops, form a beneficial, symbiotic relationship with arbuscular mycorrhizal (AM) fungi. This has triggered interest in the potential role of these fungi in sustain-able food production for an increasing population. However, it is known that many common farming practices can negatively influence both the diversity, and abundance of the AM fungi. It is therefore desirable to identify farming practices or amendments that can foster these fungal populations to increase crop and soil benefits, including yield. Cover cropping, the growing of non-food crops outside of regular crop produc-tion for the role of protecting and improving soil, has also been suggest-ed to influence both the diversity and abundance of AM fungi. A large-scale analysis of AM fungal diversity in UK agriculture provided a framework for further analysis of how cover crops, and soil amendments influence AM fungal communities. Replicated trials in both glasshouse and field conditions have shown evidence that multiple iterations of cover crops can increase the extent to which plants are colonised by AM fungi, although this had no measurable impact on yield. In the same trial, it was shown that long term application of nitrogen fertiliser influenced AM fungal community composition, but this observation was not made in a shorter validation experiment conducted at the field scale. In a sepa-rate trial, addition of a commercial AM fungal inoculum had little impact on the AM fungal community, crop growth, or yield in field conditions, further suggesting that multiple iterations of soil amendments are re-quired to cause measurable, long-term shifts in AM fungal diversity and benefit.