Authored by David D. Douds Jr.1, Joe Lee1, Joe Uknalis1, Akwasi A. Boateng1 & Christine Ziegler-Ulsh2
On farm production of arbuscular mycorrhizal (AM) fungi is suitable for vegetable and horticultural crop production because the inocula may be efficiently mixed into horticultural potting media for plant production in the greenhouse. These inocula are not amenable for use in row crop production because they are not in a form suitable for mechanical application. Experiments were conducted in which light expanded clay aggregates (LECA) and pelletized biochar were used in the media for the on-farm production of AM fungus inoculum utilizing compost and vermiculite with Paspalum notatum Flugge as the nurse host plant. Subsequent colonization assays using P. notatum failed to detect any infectivity of LECA granules, indicating that the AM fungi did not infest the granules. However, as little as 0.1 g fresh wt of biochar was sufficient to produce colonization of test plants. Biochar pellets recovered from the on-farm system used to propagate Rhizophagus intraradices exhibited 24 propagules g-1 fresh wt. These results indicate the promise of pelletized biochar as a carrier for AM fungi in inoculum production systems.