Scaling-up evaluation of field functioning of arbuscular mycorrhizal fungi.

An estimated 90% of terrestrial plants form symbiotic associations with soil fungi, and the majority of those plant species belong to families that characteristically form associations with arbuscular mycorrhizal (AM) fungi (Smith & Read, 1997). The function of these associations is largely based upon the transfer of carbon (C) from the plant to the fungus, and upon the transfer of mineral nutrients, mainly phosphorus (P), from the fungus to the host plant. Arbuscular mycorrhizal fungi may confer other benefits, including improved soil aggregate stability, plant–water relationships and resistance to plant pathogens, but these benefits have rarely been quantified in an ecosystem context (Newsham et al., 1995).